Material Properties

Fundamental Optics Gaussian Beam Optics Optical Specifications Material Properties Optical Coatings 4.1 4.7 4.8 4.9 4.2 4.3 4.5 4.6 4.23 4.10 4.12 4.13 4.14 4.16 4.17 4.19 4.20 4.21 4.22 4.18 4.24 4 www.cvimellesgriot.com Material Properties Material Material Properties ® Germanium Magnesium Fluoride Calcium Fluoride Suprasil 1 Synthetic Fused Silica UV-Grade Crystal Quartz Calcite Five Schott Glass Types Optical Crown Glass Low-Expansion Borosilicate Glass ZERODUR Infrasil 302 Sapphire Zinc Selenide Silicon Material Properties Overview Introduction Optical Properties Mechanical and Chemical Properties Lens Materials Material Properties Material 4ch_MaterialProperties_Final_a.qxd 6/23/2009 2:02 PM Page 4.1 Page 2:02 PM 6/23/2009 4ch_MaterialProperties_Final_a.qxd 4ch_MaterialProperties_Final_a.qxd 6/19/2009 4:34 PM Page 4.2

Material Properties www.cvimellesgriot.com Introduction

Fundamental Optics Glass manufacturers provide hundreds of different glass types with differing Mechanical Characteristics optical transmissibility and mechanical strengths. CVI Melles Griot has sim- The mechanical characteristics of a material are significant in many areas. plified the task of selecting the right material for an optical component by They can affect how easy it is to fabricate the material into shape, which offering each of our standard components in a single material, or in a small affects product cost. Scratch resistance is important if the component will range of materials best suited to typical applications. require frequent cleaning. Shock and vibration resistance are important There are, however, two instances in which one might need to know more for military, aerospace, or certain industrial applications. Ability to with- about optical materials: one might need to determine the performance of stand high pressure differentials is important for windows used in vacuum a catalog component in a particular application, or one might need specific chambers. information to select a material for a custom component. The information Chemical Characteristics given in this chapter is intended to help those in such situations. The chemical characteristics of a material, such as acid or stain resistance, The most important material properties to consider in regard to an optical can also affect fabrication and durability. As with mechanical charac- element are as follows: teristics, chemical characteristics should be taken into account for optics

Gaussian Beam Optics $ Transmission versus wavelength used outdoors or in harsh conditions. $ Index of refraction Cost $ Thermal characteristics Cost is almost always a factor to consider when specifying materials. $ Mechanical characteristics Furthermore, the cost of some materials, such as UV-grade synthetic $ Chemical characteristics fused silica, increases sharply with larger diameters because of the $ Cost difficulty in obtaining large pieces of the material.

Transmission versus Wavelength

A material must be transmissive at the wavelength of interest if it is to be used for a transmissive component. A transmission curve allows the optical designer to estimate the attenuation of light, at various wave- Optical Specifications lengths, caused by internal material properties. For mirror substrates, the attenuation may be of no consequence. Index of Refraction

The index of refraction, as well as the rate of change of index with wave- length (dispersion), might require consideration. High-index materials allow the designer to achieve a given power with less surface curvature, typically resulting in lower aberrations. On the other hand, most high-index flint glasses have higher dispersions, resulting in more chromatic aberration in polychromatic applications. They also typically have poorer chemical characteristics than lower-index crown glasses. Thermal Characteristics Material Properties The thermal expansion coefficient can be particularly important in appli- cations in which the part is subjected to high temperatures, such as high-intensity projection systems. This is also of concern when com- ponents must undergo large temperature cycles, such as in optical systems used outdoors. Raw and partially processed glass blanks Optical Coatings 4.2 Material Properties Fundamental Optics Gaussian Beam Optics Optical Specifications Material Properties Optical Coatings 1 d d v B will 4.3 (4.6) (4.5) 2 t continued and < 1.60 and ). The desig- ). The 1 d C n 4 F must be found from 2 t www.cvimellesgriot.com 1)/ (n -planes of polarization, Material Properties Material and 4 d over the entire transmission 1 n 5 ( 3 Material Properties 4 - and p = 2 C d l 10 − 3 2 B is typically given only for the lesser is typically given # l i T + , which becomes the surface-to-surface c t 2 2 C l > 50. The others are flint glasses. > 50. The − 2 d 2 B l + 1 . 2 C -value, defined to be v -value, i l − 1 T value is normally the most useful, but some applications is normally the most useful, value 2 B > 1.60 and v e ln l is tabulated, use linear interpolation. d i are given by the glass manufacturer. Values for other glasses can Values are given by the glass manufacturer. c 1 t 3 1 C −= , the wavelength, must be in micrometers, and the constants must be in micrometers, , the wavelength, =− l 2 n m > 55, or n d be obtained from the manufacturer’s literature. This equation yields an index This literature. be obtained from the manufacturer’s that is accurate to better than 1 value The refractive index of glass from 365 to 2300 nm can be calculated by refractive index of glass from 365 to 2300 The using the formula Here distance along a particular ray, must be determined by ray tracing. It is must be determined distance along a particular ray, necessary to account separately for the s both planes at the end and it is usually sufficient to average results for of the calculation. require that transmittance be known along other ray paths, or that it be or that be known along other ray paths, require that transmittance is easily method outlined above The lens surface. averaged over the entire of t Values such cases. extended to encompass thickness. Then thickness. other than those transmittance at wavelengths When it is necessary to find for which T complete Fresnel formulas for arbitrary angles of incidence. The angles The formulas for arbitrary angles of incidence. complete Fresnel t of incidence will be different at the two surfaces; therefore, generally be unequal. Distance v nations F and C stand for 486.1 nm and 656.3 nm, respectively. Here, v Here, nm, respectively. nations F and C stand for 486.1 nm and 656.3 shows how the index of refraction varies with wavelength. The smaller The with wavelength. shows how the index of refraction varies Glasses are roughly divided into two the faster the rate of change is. is, categories: are those with n Crown glasses crowns and flints. through where the bar denotes averaging. In portions of the spectrum where In portions of the spectrum denotes averaging. where the bar for is strong, a value absorption REFRACTIVE INDEX AND DISPERSION Schott Optical Glass catalog offers nearly 300 different optical glasses. The among these glasses is the the most important difference lens designers, For of index with wavelength). index of refraction and dispersion (rate of change an optical glass is specified by its index of refraction at a wavelength Typically, nm (the helium d-line), in the middle of the visible spectrum, usually 587.56 and by the Abbé v The on-axis T The range, and even better in the visible spectrum. range, 2 c1 t (4.2) (4.3) (4.4) (4.1) denotes e T is the absorption must be known or m n the corresponding internal i are functions of wavelength. T n . Typically, internal transmittance . Typically, and ⎤ ⎥ ⎦ is the lens center thickness. This allows This is the lens center thickness. c 2 2 c ic for a lens at any wavelength of interest, first for a lens at any wavelength t Tt e c t m − 1 or the T 2 i 1 c ic t the single-pass transmittance of the first surface, and t the single-pass transmittance of the first surface, Tt 2 1 ⎞ ⎟ ⎠ t must be found from these. Thus must be found from these. ln ( ) ln ( ) 1 1 ⎡ ⎢ ⎣ − + 2 12 1 n n 12 12 that connect these variables in the on-axis case are presented below. in the on-axis that connect these variables =− + is the base of the natural system of logarithms, is the base of the natural system of logarithms, ⎛ ⎜ ⎝ == , and m e =− + = ei c2 12 t r tt r r m TttTtte is tabulated as a function of wavelength for two distinct thicknesses is tabulated as a function of wavelength i where calculated from the material dispersion formula found in the next section. results are monochromatic. Both m These calculate either T To the desired external irradiance transmittance, the desired external irradiance transmittance, and where the single-pass transmittance of the second surface, then the single-pass transmittance of the second surface, The most important optical properties of a material are its internal and of a material are important optical properties most The The indexes. and refractive reflectances, surface external transmittances, formulas TRANSMISSION is the single-pass irradiance transmittance of an External transmittance transmittance is the single-pass irradiance trans- optical element. Internal transmittance of any surface reflection losses (i.e., mittance in the absence transmittance is of paramount importance when of the material). External lens system because external trans- selecting optics for an image-forming Transmittance reflections between lens surfaces. mittance neglects multiple If higher. measured with an integrating sphere will be slightly Optical Properties Optical find the value of absorption coefficient m find the value T is the single-surface single-pass irradiance reflectance at normal incidence is the single-surface single-pass irradiance reflectance index refractive formula. The as given by the Fresnel for the possibility that the lens surfaces might have unequal transmittances for the possibility that the lens surfaces might have one is coated and the other is not). Assuming that both (for example, surfaces are uncoated, transmittance, transmittance, coefficient of the lens material, and t 4ch_MaterialProperties_Final_a.qxd 6/19/2009 4:34 PM Page 4.3 Page 4:34 PM 6/19/2009 4ch_MaterialProperties_Final_a.qxd 4ch_MaterialProperties_Final_a.qxd 6/19/2009 4:35 PM Page 4.4

Material Properties www.cvimellesgriot.com

Fundamental Optics OTHER OPTICAL CHARACTERISTICS Refractive Index Homogeneity APPLICATION NOTE The tolerance for the refractive index within melt for all Schott fine annealed Fused-Silica Optics glass used in CVI Melles Griot catalog components is 81#1044. Synthetic fused silica is an ideal optical material for many laser Furthermore, the refractive index homogeneity, a measure of deviation 4 applications. It is transparent from as low as 180 nm to over within a single piece of glass, is better than 82#10 5. 2.0 mm, has low coefficient of thermal expansion, and is resistant to scratching and thermal shock. Striae Grade

Striae are thread-like structures representing subtle but visible differences in refractive index within an optical glass. Striae classes are specified in ISO 10110. All CVI Melles Griot catalog components that utilize Schott optical glass are specified to have striae that conform to ISO 10110 class Gaussian Beam Optics 5 indicating that no visible striae, streaks, or cords are present in the glass.

Stress Birefringence

Mechanical stress in optical glass leads to birefringence (anisotropy in index of refraction) which can impair the optical performance of a finished component. Optical glass is annealed (heated and cooled) to remove any residual stress left over from the original manufacturing process. Schott Glass defines fine annealed glass to have a stress birefringence of less than or equal to 10 nm/cm for diameters less than 300 mm and for thicknesses less than or equal to 60 mm. For diameters between 300 and 600 mm and for thicknesses between 60 and 80 mm, stress birefringence would be less than or equal to 12 nm/cm. Optical Specifications Material Properties

Unpolished glass substrates Optical Coatings 4.4 Material Properties Fundamental Optics Gaussian Beam Optics Optical Specifications Material Properties Optical Coatings 4.5 415 158 522 610 542 480 620 112 780 1100 Knoop Hardness www.cvimellesgriot.com Material Properties Material Material Properties APPLICATION NOTE APPLICATION Glass Manufacturers contain products catalogs of optical glass manufacturers The it However, covering a very wide range of optical characteristics. exhibit the most in mind that the glass types that should be kept desirable properties in terms of index of refraction and dispersion often have the least practical chemical and poor chemical and Furthermore, mechanical characteristics. mechanical attributes translate directly into increased component costs because working these sensitive materials increases fabrication time and lowers yield. Please contact us before specifying an exotic glass in an optical design so that we can advise you of the impact that that choice will have on part fabrication. Material Magnesium Fluoride Calcium Fluoride Fused Silica BK7 (N-BK7) Optical Crown Glass Borosilicate Glass Zerodur Zinc Selenide Silicon Germanium Microhardness A mechanical property of glass is microhardness. most important The scribe is placed on the glass surface under precisely specified diamond and the Knoop indentation is then measured. The The a known force. used to measure the hardness of a microhardness tests are Vickers respectively. freshly fractured surface, polished surface and a Materials Optical for Standard Values Knoop Hardness that involve chlorofluorocarbons (CFCs) to those that Climatic resistance expresses the susceptibility of a glass Climatic resistance expresses the susceptibility induced by the test. A rating of 1 indicates little or no change induced by the test. A rating of 1 indicates little Mechanical and chemical properties of glass are important to lens of glass are important and chemical properties Mechanical to the user, can also be significant properties These manufacturers. will be used in a harsh environment. especially when the component and special handling may be needed Different polishing techniques is the glass is hard or soft, or whether it depending on whether or alkali. extremely sensitive to acid glass manufacturers properties of glasses, quantify the chemical To stain to four categories: climatic resistance, rate each glass according and alkali and phosphate resistance. acid resistance, resistance, Climatic Resistance cloudy film to appear on the surface of some Humidity can cause a optical glass. In this test, glass is placed in a to high humidity and high temperatures. environment and subjected to a temperature water-vapor-saturated glass The evaporation. cycle which alternately causes condensation and the amount of surface is given a rating from 1 to 4 depending on scattering Mechanical and Chemical Properties Chemical and Mechanical 4 means a significant after 30 hours of climatic change; a rating of change occurred in less than 30 hours. Stain Resistance solutions, acidic water Stain resistance expresses resistance to mildly a few drops of a mild such as fingerprints or perspiration. In this test, will A colored stain, caused by interference, acid are placed on the glass. A rating from 0 to 5 is given to appear if the glass starts to decompose. depending on how much time elapses before stains occur. each glass, hours of exposure; a A rating of 0 indicates no observed stain in 100 than 0.2 hours. rating of 5 means that staining occurred in less Acid Resistance glass to stronger acidic Acid resistance quantifies the resistance of a Acid resistance can be particularly important to lens manufac- solutions. turers because acidic solutions are typically used to strip coatings from rating from 1 to 4 indicates A glass or to separate cemented elements. from progressively less resistance to a pH 0.3 acid solution, and values 51 to 53 are used for glass with too little resistance to be tested with such a strong solution. Alkali and Phosphate Resistance Alkali resistance is also important to the lens manufacturer since the solution. Phosphate place in an alkaline polishing process usually takes from resistance is becoming more significant as users move away cleaning methods In each may be based on traditional phosphate-containing detergents. alkali or phosphate resis- a two-digit number is used to designate case, from 1 to 4, indicates the length of time that first number, The tance. and the second elapses before any surface change occurs in the glass, digit reveals the extent of the change. 4ch_MaterialProperties_Final_a.qxd 6/19/2009 4:35 PM Page 4.5 Page 4:35 PM 6/19/2009 4ch_MaterialProperties_Final_a.qxd 4ch_MaterialProperties_Final_a.qxd 6/19/20094:35PMPage4.6

Optical Coatings Material Properties Optical Specifications Gaussian Beam Optics Fundamental Optics identical tothoseofBK7. arsenic-free versionofBK7islabeledN-BK7withmostopticalproperties BK7, andtransmissiondeeperintotheultravioletrange. The leadand requiring ahighindexofrefraction,thedesirablechemicalproperties of lengths aslow300nm.This specialglassisusefulinapplications industry. Avariant ofBK7,designatedUBK7,hastransmissionatwave- Because oftheseproperties, BK7isusedwidelythroughouttheoptics of BK7isitsexcellenttransmittance, atwavelengths aslow350nm. changes or substitution on any optical component. optical any on substitution or changes CVI Melles Griot reserves the right, without prior notice, to make material make to 4.6 notice, prior without right, the reserves Griot Melles CVI total lessthan0.029mm bubble andinclusioncontentofBK7isverylow, withacross-section not scratcheasilyandcanbehandledwithoutspecialprecautions. The ment duringpolishingisnotnecessary. BK7,arelativelyhardglass, does Griot products. BK7performswellinchemicaltestssothatspecialtreat- A borosilicatecrownglass, BK7,isthematerialusedinmanyCVIMelles BK7 OPTICALGLASS manufacturers, areavailable onlyonspecialrequest. published intherestofthischapter, ormaterialstraceabletospecific these means. Materialshavingtolerancesmorerestrictivethanthose historical experience. Individualmaterialspecimensmaydeviatefrom The followingphysicalconstantvalues arereasonableaveragesbasedon repeatable, consistentperformance. materials fromreputableglassmanufacturers. The resultisreliable, considerable careinitsmaterialselection,usingonlyfirst-classoptical striae, bubbles, inclusions, orvariations inindex.CVIMellesGriottakes the materialused.Noamountofskillduringmanufacturecaneradicate The performanceofopticallensesandprismsdependsonthequality result inasignificantchangeopticalproperties. glasses madebyotherglassmanufacturersbutonlywhenthisdoesnot published bySchottGlass. CVIMellesGriotoccasionallyusescorresponding Glass typedesignationsandphysicalconstantsarethesameasthose also usedinprisms, mirrorsubstrates, andotherproducts. the materialsusedinCVIMellesGriotlenses. Someofthesematerialsare annealed glass, andseveralothermaterials. The followingtableidentifies CVI MellesGriotlensesaremadeofsyntheticfusedsilica,BK7gradeAfine Lens Materials Material Properties 2 per 100cm 3 . Anotherimportantcharacteristic Lens MaterialTable CIMl ff i G ll M *CVI under ISO14001requirements.Contactyourlocalofficefordetails. *CVI MellesGriotoffersarangeoflead-andarsenic-freeglasseswhicharemanufactured icSlnd LXZS MENP-ZnSe PLCX-MF PLCX-ZnSe PLCX-CFIR BICX-MF PLCX-CFUV andarsenic-freeglasses) (including lead- Various GlassCombinations Zinc Selenide Magnesium Fluoride PLCC-SF11 Calcium Fluoride Sapphire Low-Expansion BorosilicateGlass(LEBG) PLCX-SF11 Optical CrownGlass SelectedLPXseries SF11, Grade-AFine Annealed LMSandSelectedLPXseries LAI BaK1, GradeAFine Annealed SK11 andSF5,GradeAFine Annealed LaSFN9, GradeAFine Annealed PLCX-EUV BK7, GradeAFine Annealed Synthetic FusedSilica,ExcimerGrade LUP-UV Synthetic FusedSilica,UVGrade Material ihfd f h hi l f i d d l f LPX-C LAG PXS L OAS LSL YAN HAN FAP GLC LAL LBM YAP HAP AAP LAO LAN Selected CMPseries LAP BFPL-C MENP-C CLCC-C SCX-C RCX-C LCP-C BICX-C LDX-C PLCX-C BFPL-UV CLCX-UV SCX-UV RCX-UV BICX-UV LUD-UV PLCX-UV C-FVRCC-CFUV RCX-CFUV Product Code Material Properties www.cvimellesgriot.com LPK-C MENN-C CLCX-C SCC-C RCC-C LCN-C BICC-C LDK-C PLCC-C CLCC-UV SCC-UV RCC-UV BICC-UV LUB-UV PLCC-UV LUK-UV Fundamental Optics Gaussian Beam Optics Optical Specifications Material Properties Optical Coatings 4.7 3 3 3 3 1 1 1 1 ) E 4 4 2 4 4 2 4 4 4 4 10 10 10 10 10 10 10 10 10 10 /°C (parallel to c 6 /°C (perpendicular 6 3 4 www.cvimellesgriot.com 1.41735 1.41618 1.41377 1.41164 1.40877 1.40429 1.40216 1.40086 1.39952 1.39917 1.44127 1.42933 1.42522 1.42358 4 10 Material Properties Material 10 1.35737865# 8.23767167# 5.65107755# 1.88217800# 8.95188847# 5.66135591# 2.49048620 4.87551080# 3.98750310# 2.31203530 4.13440230# 5.04974990# Material Properties ======1 2 3 1 2 3 3 1 2 3 1 2 3.177 g/cm B B C C B C C C C 8.48# 138.5 GPa 0.271 415 to c axis) 13.70# axis) 1585°C B B B ) Extraordinary Ray (n O Density Expansion 1.40447 1.40334 1.40102 1.39896 1.39620 1.39188 1.38983 1.38859 1.38730 1.38696 1.42767 1.41606 1.41208 1.41049 Melting Point (Ordinary Ray) (Ordinary Poisson’s Ratio Poisson’s Knoop Hardness Young’s Modulus Young’s (Extraordinary Ray) (Extraordinary Dispersion Constants Dispersion Dispersion Constants Dispersion Coefficient of Thermal Coefficient of Thermal 244 308 248 257 266 280 325 337 351 355 193 213 222 226 (nm) Ordinary Ray (n Wavelength Index of Refraction Index of Refraction Magnesium Fluoride Constants Magnesium Fluoride Refractive Index of Magnesium Fluoride 8.0 is a rugged 2 3.0 6.0 ) is a tetragonal positive birefringent crystal ) is a tetragonal positive 0.20 2 WAVELENGTH IN MICROMETERS WAVELENGTH 0.15 0.25 4.0 a popular choice for VUV and excimer laser windows, a popular choice for VUV

0.10

2

80 40 60 20

100 TRANSMITTANCE PERCENT EXTERNAL PERCENT izers, and lenses. polarizers, material as well as mechanical and thermal resistant to chemical etching and resistance to laser damage UV transmission shock. High-vacuum MgF make External transmittance for 5-mm-thick uncoated magnesium fluoride Magnesium Fluoride Magnesium Magnesium Fluoride (MgF grown using the vacuum Stockbarger technique. MgF technique. Stockbarger grown using the vacuum 4ch_MaterialProperties_Final_a.qxd 7/28/2009 3:55 PM Page 4.7 Page 3:55 PM 7/28/2009 4ch_MaterialProperties_Final_a.qxd 4ch_MaterialProperties_Final_a.qxd 6/19/20094:35PMPage4.8

Optical Coatings Material Properties Optical Specifications Gaussian Beam Optics Fundamental Optics damage resistanceinCaF Unfortunately, achievingacceptabledeepultraviolettransmissionand synthetically usingthetime-andenergy-consumingStockbargermethod. applications intheultravioletandinfraredspectra.CaF deep ultravioletapplications. stress-birefringence characteristicsrequiredforthemostdemanding center formation,lowfluorescence, highhomogeneity, andlow mission (downto157nm),highdamagethreshold,resistancecolor- Excimer-grade CaF regulation ofvacuum andannealing processparameters. allow tightertemperaturecontrolduringcrystalgrowth,aswellbetter make alterationstothetraditionalStockbargerapproach.These changes homogeneity andstressbirefringencehavealsocausedproducersto at allstagesoftheproductionprocess. The needsforimprovedmaterial tion andprocessingmethodstoidentifyremovevarious impurities 193 nmandbelow, manufacturershaveintroducedavariety ofinspec- To meettheneedforimprovedcomponentlifetimeandtransmissionat mined material. in theinfrared,anditcompletelyeliminatespossibilityofusing CaF prisms, andmirrorsubstrates. for usewithexcimerlasers. Itcanbemanufacturedintowindows, lenses, ultraviolet. CaF Traditionally, ithasbeenusedprimarilyintheinfrared,ratherthan 4.8 calcium fluoride transmittancefor5-mm-thick uncoated External Calcium fluoride(CaF Calcium Fluoride 2

PERCENT EXTERNAL transmits overthespectralrangeofabout130nmto10 Material Properties

TRANSMITTANCE 100 20 40 60 80 0.2 2 occurs naturallyandcanbemined.Itisalsoproduced 2 provides thecombinationofdeepultraviolettrans- WAVELENGTH INMICROMETERS 2 ), acubicsingle-crystalmaterial,haswidespread .0 4082.0 0.60.4 0.8 2 requires muchgreatermaterialpuritythan 1.0 2 4.0 is anidealmaterial 10.0 m m. Calcium FluorideConstants Refractive IndexofCalciumFluoride Wavelength 0.266 0.257 0.248 0.193 0.587 0.486 0.355 0.308 ( 0.65 m 8.0 7.0 6.0 5.0 4.0 3.0 2.5 2.0 1.5 1.0 0.7 m) Thermal Coefficientof Coefficient ofThermal Dispersion Constants Young’s Modulus Knoop Hardness Poisson’s Ratio Melting Point Refraction Expansion Density 1.75# 3.18 g/cm B 1360°C dn/ 158 0.26 C C C B B 18.9# 3 2 1 3 2 1 dT ======3.8484723 0.4710914 0.5675888 1200.5560 0.01007833 0.00252643 = 10 10 Material Properties 4 4 7 3 psi www.cvimellesgriot.com @ 25°C 10.6# 6 /°C (20°–60°C) Index ofRefraction 10 1.462 1.465 1.468 1.501 1.349 1.369 1.385 1.398 1.409 1.417 1.421 1.423 1.426 1.428 1.431 1.432 1.433 1.437 1.446 1.453 4 6 /°C Fundamental Optics Gaussian Beam Optics Optical Specifications Material Properties Optical Coatings 4.9 /ºC 5 /ºC @ 25°C 7 1.48164 1.47921 1.47447 1.46962 1.46669 1.46622 1.46578 1.46313 1.46301 1.46156 1.46071 1.46008 1.45846 1.45702 1.45637 1.45542 1.45419 1.45168 1.44963 1.44859 1.44670 1.56013 1.50833 1.49968 1.48564 3 4 5 4 0.5 10 4 10 0.0046791 0.0135121 97.9340025 0.6961663 0.4079426 0.8974794 Index of Refraction 10 ======1 2 3 www.cvimellesgriot.com 1 2 3 # 900°C maximum 5.5# 590 2.20 g/cm 67.88 1.28# B B C C C 2 0.177 cal/g/ºC @ 25°C B Material Properties Material Material Properties Density Specific Heat Abbé Constant Knoop Hardness Dispersion Constants Dispersion 5 4 Temperature (0° to 700°C) Temperature 10 # 3 Homogeneity (maximum index Homogeneity (maximum variation over 10-cm aperture) variation over 10-cm 8 Change of Refractive Index with Index Change of Refractive Coefficient of Thermal Expansion Continuous Operating Temperature Continuous Operating (nm) 337.0 365.5 404.7 435.8 447.1 486.1 488.0 514.5 546.1 587.6 632.8 656.3 752.5 905.0 325.0 441.6 532.0 694.3 193.4 248.4 266.0 308.0 1064.0 1153.0 1319.0 Wavelength * Accuracy Refractive Index of Suprasil 1* Suprasil 1 Constants 4.0 3.0 1.0 0.25 GTH IN MICROMETERS WAVELEN 0.20 0.30 2.0

0.15

80 40 60 20

C S E MITTAN 100 TRAN

C ENT EXTERNAL ENT PER External transmittance for 10-mm-thick uncoated suprasil 1 Suprasil 1 silica with high chemical purity and excellent Suprasil 1 is a type of fused ppm, With a metallic content less than 8 multiple axis homogeneity. Suprasil transmission and minimal fluorescence. Suprasil 1 has superior UV lenses and prisms fluorescence UV windows, 1 is primarily used for low is required. where multiple axis homogeneity 4ch_MaterialProperties_Final_a.qxd 6/19/2009 4:35 PM Page 4.9 Page 4:35 PM 6/19/2009 4ch_MaterialProperties_Final_a.qxd 4ch_MaterialProperties_Final_a.qxd 6/19/20094:35PMPage4.10

Optical Coatings Material Properties Optical Specifications Gaussian Beam Optics Fundamental Optics UV-grade $ $ $ $ $ quartz: Synthetic fused-silicalensesofferanumberofadvantages overglassorfused of onlyaboutonepartpermillion. material iscolorlessandnon-crystalline, andithasanimpuritycontent factured byflamehydrolysistoextremelyhighstandards. The resultant The syntheticfused-silicamaterialsusedbyCVIMellesGriotaremanu- expansion, andisresistanttoscratchingthermalshock. is transparentoverawidespectralrange, hasalowcoefficientofthermal of siliconandoxygen,isanidealopticalmaterialformanyapplications. It Synthetic fusedsilica(amorphoussilicondioxide),bychemicalcombination UV-Grade SyntheticFusedSilica used inthisregion,Infrasil302maybeabetterchoice. due toresonanceabsorptionbyOHchemicalbonds. Iftheopticistobe fluctuate significantlyinthenearinfraredbetween900nmand2.5 The batch-to-batchinternaltransmittanceofsyntheticfusedsilicamay tolerance ensureshighlypredictablelensspecifications. cations, UV-grade syntheticfusedsilicaisanidealchoice. Itstightindex response towavelengths longer than290nm.Indeepultravioletappli- excited at254nm).UV-grade syntheticfusedsilicadoesnotfluorescein fluorescence levels(approximately0.1%thatoffusednaturalquartz the highesttransmission(especiallyindeepultraviolet)andverylow 4.10 x-rays, gammarays, andneutrons. Much higherresistancetoradiationdarkening fromultraviolet, Increased hardnessandresistancetoscratching Wider thermaloperatingrange resistance tothermalshockoverlargetemperatureexcursions Low coefficientofthermalexpansion,whichprovidesstabilityand Greater ultravioletandinfraredtransmission Material Properties synthetic fusedsilica(UVGSFS or Suprasil1)isselectedtoprovide m m Synthetic FusedSilicaConstants Continuous Operating Temperature Coefficient ofThermalExpansion Change ofRefractive Indexwith variation over10-cmaperture) Homogeneity (maximumindex Temperature (0°to700°C) Dispersion Constants Knoop Hardness Abbé Constant Specific Heat Density C B C C B B 1.28# 67.88 2 0.177 cal/g/ºC@25°C 2.20 g/cm 5.5# 900°C maximum 522 # 3 2 1 3 2 1 Material Properties ======10 0.8974794 0.4079426 0.6961663 97.9340025 0.0135121 0.0046791 www.cvimellesgriot.com 10 4 10 0.5 4 5 4 3 7 @ 25°C /ºC 5 /ºC Fundamental Optics Gaussian Beam Optics Optical Specifications Material Properties Optical Coatings 4.11 5.0 500 1.45024 1.44963 1.44920 1.44805 1.44692 1.44578 1.44462 1.44402 1.44267 1.44217 1.44087 1.43951 1.43809 1.43659 www.cvimellesgriot.com Material Properties Material (nm) Refraction 1014.0 1064.0 1100.0 1200.0 1300.0 1400.0 1500.0 1550.0 1660.0 1700.0 1800.0 1900.0 2000.0 2100.0 Material Properties Wavelength Index of 4.0 4.5 420 460

1.46071 1.46008 1.45846 1.45840 1.45702 1.45670 1.45637 1.45542 1.45515 1.45356 1.45298 1.45282 1.45247 1.45170

S GS F UV

(nm) Refraction

532.0 546.1 587.6 589.3 632.8 643.8 656.3 694.3 706.5 786.0 820.0 830.0 852.1 904.0 BK7 Wavelength Index of 300 340 380 1.48054 1.47858 1.47671 1.47513 1.47454 1.46962 1.46669 1.46622 1.46498 1.46372 1.46313 1.46301 1.46252 1.46156 GTH IN NANOMETERS WAVELEN GTH IN MICROMETERS WAVELEN

BK7 (nm) Refraction 330.3 340.4 351.1 361.1 365.0 404.7 435.8 441.6 457.9 476.5 486.1 488.0 496.5 514.5 1.5 2.0 2.5 3.0 3.5 220 260 Wavelength Index of

1.0

180

S GS F UV 1.58529 1.56572 1.55051 1.53431 1.52275 1.52008 1.51337 1.50840 1.50003 1.49591 1.49404 1.49099 1.48873 1.48719 b) UPPER LIMITS a) LOWER LIMITS 5 4 10 0.5

# 140

3

60 40 20 80 80 60 40 20

C S C S E MITTAN E MITTAN TRAN TRAN 8 100 100

C C ENT EXTERNAL ENT PER ENT EXTERNAL ENT PER (nm) Refraction 180.0 190.0 200.0 213.9 226.7 230.2 239.9 248.3 265.2 275.3 280.3 289.4 296.7 302.2 Wavelength Index of * Accuracy Refractive Index of UV-Grade Synthetic Fused Silica* Synthetic Fused Refractive Index of UV-Grade Comparison of uncoated external all 10 mm in thickness transmittances for UVGSFS and BK7, 4ch_MaterialProperties_Final_a.qxd 6/19/2009 4:35 PM Page 4.11 Page 4:35 PM 6/19/2009 4ch_MaterialProperties_Final_a.qxd 4ch_MaterialProperties_Final_a.qxd 6/19/20094:35PMPage4.12

Optical Coatings Material Properties Optical Specifications Gaussian Beam Optics Fundamental Optics 4.12 crystal quartz transmittancefor10-mm-thick uncoated External Crystal QuartzConstants shown below. The dispersionfortheindexofrefractionisgivenbyLaurentseries ization-resistant Brewsterwindowsforargonlasers. most commonlyusedforhigh-damage-thresholdwaveplates andsolar- to minimizeinclusionsandrefractiveindexvariation. Crystalquartzis a hydrothermalprocess. CrystalquartzfromCVIMellesGriotisselected Crystal quartzisapositiveuniaxialbirefringentsinglecrystalgrownusing Crystal Quartz Thermal ExpansionCoefficient

PERCENT EXTERNAL Material Properties

TRANSMITTANCE 100 20 60 40 80 Dispersion Constants Dispersion Constants 0.15 Transmission Range (Extraordinary Ray) h Young’s Modulus 2 Knoop Hardness =A (Ordinary Ray) .003 1.5 0.30 0.20 Melting Point epniua 76.5Gpa Perpendicular epniua 13.2 Perpendicular 0 WAVELENGTH INMICROMETERS =A Density 0.25 aall7.1 Parallel aall97.2Gpa Parallel 1 l 2 = A l 2 2 2.64 g/cm 741 1463°C 0.170–2.8 A A A A A A A A A A A A 5 4 3 2 1 0 5 4 3 2 1 0 0.5 A l ======# 4 3 # 9.36476# 4 1.65180# 1.07900# 4 2.38490 5.92362# 4 1.34143# 1.05400# 4 2.35728 10 10 1.94741# 1.25900# 4.45368# 1.17000# 4 A l 4 3 6 6 4 m /°C 6 m /°C A l 10 10 10 10 10 10 8 5 2.5 4 4 4 4 4 4 10 10 10 10 8 4 2 8 4 2 4 4 4 4 7 2 7 2 3.5 Refractive IndexofCrystalQuartz Wavelength 2010 1550 1320 1064 (nm) 226 222 213 193 515 488 458 442 400 355 351 337 325 308 280 266 257 248 244 980 860 820 800 780 755 694 670 633 590 532 ne fRfato IndexofRefraction Index ofRefraction Ordinary Ray(n 1.61859 1.62238 1.63224 1.66091 1.54787 1.54955 1.55181 1.55324 1.55772 1.56463 1.56533 1.56817 1.57097 1.57556 1.58533 1.59164 1.59620 1.60175 1.60439 1.52073 1.52761 1.53068 1.53410 1.53531 1.53724 1.53798 1.53837 1.53878 1.53932 1.54080 1.54148 1.54264 1.54421 1.54690 O ExtraordinaryRay(n ) Material Properties www.cvimellesgriot.com 1.63033 1.63427 1.64452 1.67455 1.55711 1.55885 1.56119 1.56266 1.56730 1.57446 1.57518 1.57812 1.58102 1.58577 1.59589 1.60242 1.60714 1.61289 1.61562 1.52863 1.53596 1.53922 1.54282 1.54409 1.54612 1.54688 1.54729 1.54771 1.54827 1.54981 1.55051 1.55171 1.55333 1.55610 E ) Fundamental Optics Gaussian Beam Optics Optical Specifications Material Properties Optical Coatings ) E 4.13 3 5 4 4 10 10 1.47486 1.47482 1.47528 1.47916 1.47792 1.47803 1.47765 1.47722 1.47681 1.47638 1.47597 1.47555 1.47513 1.48473 1.48289 1.48157 1.48056 1.47980 1.53336 1.50392 1.49307 1.48775 www.cvimellesgriot.com 3 0.01182893 Material Properties Material 105.58893 0.01583669 4 0.3468576 7.741535# 12.185616 1.56630 1.41096 0.28624 8.418192# 1.183488 0.03413054 Material Properties ======) Extraordinary Ray (n 1 2 3 1 2 3 1 2 3 1 2 3 O 3 1339 °C B C B B C B B C C C C B 2.71 g/cm 1.62149 1.61921 1.61698 1.64068 1.63889 1.63715 1.63541 1.63365 1.63186 1.62995 1.62798 1.62594 1.62379 1.65467 1.65041 1.64724 1.64470 1.64260 1.76906 1.69695 1.67276 1.66132 Density Ordinary Ray (n Index of Refraction Index of Refraction Melting Point (Ordinary Ray) (Ordinary Mohs Hardness (Extraordinary Ray) (Extraordinary Dispersion Constants Dispersion Dispersion Constants Dispersion 650 750 850 950 250 350 450 550 (nm) 2150 2250 2350 1150 1650 1250 1350 1450 1550 1750 1850 1950 2050 1050 Wavelength Refractive Index of Calcite Calcite Constants 3.5 3.0 2.0 extraordinary ray 1.0 ordinary ray GTH IN MICROMETERS WAVELEN ) is a naturally occurring negative uniaxial crystal which ) is a naturally occurring 3

80 40 60 20

C S E MITTAN 100 TRAN

C ENT EXTERNAL ENT PER Typical external transmittance for 10-mm-thick calcite Typical exhibits pronounced birefringence. Strong birefringence and a wide trans- exhibits pronounced birefringence. this mineral popular for making polarizing mission range have made in Although it can now be grown artificially prisms for over 100 years. Africa, and Siberia. optical calcite is mined in Mexico, most small quantities, remains a time-consuming task requiring spe- optical grade crystals Finding soft- polishing calcite is also challenging due to the Cutting and cial skills. explain factors These its tendency to cleave easily. ness of the mineral and were developed, calcite prisms even many years after the techniques why, of polarizers. remain expensive when compared to other types from piece to will vary Since calcite is a natural crystal, the transmission In general, a 10 mm thick sample will fall within the following piece. 500–2300 nm, 86–88%. ranges: 350 nm, 40–45%; 400 nm, 70–75%; Calcite Calcite (CaCO 4ch_MaterialProperties_Final_a.qxd 6/19/2009 4:35 PM Page 4.13 Page 4:35 PM 6/19/2009 4ch_MaterialProperties_Final_a.qxd 4ch_MaterialProperties_Final_a.qxd 6/19/20094:35PMPage4.14

Optical Coatings Material Properties Optical Specifications Gaussian Beam Optics Fundamental Optics 4.14 Physical ConstantsofFiveSchottGlasses processes canbefoundintheSchottOpticalGlasscatalog. numerical dataandamoredetaileddiscussionofthevarious testing chemical characteristicsandmechanicalconstants, arelisted.Further prisms. Indexofrefractionaswellthemostcommonlyrequired These typesareusedinmostCVIMellesGriotsimplelensproductsand and N-BaK1denotingtheleadarsenic-freeversionsofBK7BaK1. for SchottopticalglasstypesBK7,SF11,LaSFN9,BaK1,andF2,withN-BK7 The followingtableslistthemostimportantopticalandphysicalconstants Five SchottGlassTypes Abbé Factor (v Stress Birefringence, nm/cm,Yellow Light Young’s Modulus(dynes/mm Melt-to-Melt MeanIndexTolerance Density (g/cm no ades60406050420 0.220 2.3 1.3 1.0 530 0.252 1.2 2.0 3.3 0.286 630 1.0 1.0 2.0 0.235 450 1.2 1.0 1.0 0.206 610 2.0 2.3 1.0 Poisson’s Ratio Knoop Hardness Phosphate Resistance Alkali Resistance Acid Resistance Stain Resistance Climate Resistance Transition Temperature Constants ofDispersionFormula: Coefficient ofLinearThermal Expansion(cm/°C): B = C C C B B 4 3 2 1 3 2 1 20º to= 30º to= Material Properties 3 d ) ) 0º 8.3# 300ºC 70ºC 2 ) 2.00179144# 6.00069867# 2.31792344# 1.03560653# .362217880 .781411356 1.34533359 8.81511957 1.12365662 1.92900751 1.97888194 1.17490871 1.73848403 1.01046945 1.03961212 BK7 (N-BK7) 8.20# 7.1# 8 557ºC 64.17 2.51 0.0005 10 00010 21221 104 104 10 9 6 6 104 104 104 10 2 2 3 1 6.15960463# 1.36068604# 3.11168974# 1.21922711# 6.60# 6.8# 6.1# 8 505ºC 25.76 4.74 0.0005 SF11 10 104 104 10 9 6 6 104 104 104 10 2 2 2 1 5.27381770# 1.18537266# 3.20435298# 1.66256540# 1.09# 8.4# 7.4# 8 Glass Type aF9BaK1(N-BaK1) LaSFN9 703ºC 32.17 4.44 0.0005 10 104 104 10 10 6 6 104 104 104 10 2 2 2 1 2.22284402# 6.44742752# 3.09276848# 1.07297751# 7.30# 8.6# 7.6# 8 592ºC 57.55 3.19 0.0005 10 104 104 10 # 9 6 6 104 104 104 104 10 Material Properties 2 2 3 1 1 www.cvimellesgriot.com 4.70450767# 9.97743871# 9.37357162# 2.09073176# 1.11886764# 5.70# 9.2# 8.2# 8 438ºC 36.37 3.61 0.0005 F2 10 104 104 10 9 6 6 104 104 104 104 10 2 2 3 1 1 Fundamental Optics Gaussian Beam Optics Optical Specifications Material Properties Optical Coatings 4.15 IR IR IR IR Spectral arc Blue arc Red www.cvimellesgriot.com 2 2 H Ce arc IR Hg arc IR Hg arcHg arc IR IR Ar laserAr laserAr laser Blue Green Green Ar laserAr laserAr laser Blue Ar laser Blue Blue Blue Ar laser Green Ar laser UV Ar laser UV Material Properties Material Nd laser Green Nd laser IR Ruby laser Red GaAs laser IR HeCd laser Blue HeNe laser Red GaAlAs laser IR InGaAsP laser IR Material Properties t s F e Hg arc Green d He arc Yellow g Hg arc Blue h Hg arc Violet CH D Na arc Yellow F’ Cd arc Blue Fraunhofer 1.60062 1.67359 1.59744 1.66682 — — LaSFN9 BaK1 (N-BaK1) F2 Designation Source Region Refractive Index, n — — l (nm) BK7 (N-BK7) SF11 904.0 1.50893 1.75970 1.82785 1.56325 1.60528 830.0852.1 1.51020 1.50980 1.76311 1.76200 1.83098 1.82997 1.56466 1.56421 1.60739 1.60671 496.5501.7 1.52165 1.52130 1.80347 1.80205 1.86645 1.86524 1.57852 1.57809 1.63046 1.62969 488.0 1.52224 1.80590 1.86852694.3786.0 1.57927 1.51322 1.51106 1.63178 1.77231 1.76558 1.83928 1.83323 1.56816 1.56564 1.61288 1.60889 351.1 1.53894 821.0 1.51037 1.76359 1.83142 1.56485 1.60768 546.1587.6589.3 1.51872632.8 1.51680643.8 1.51673656.3 1.51509 1.79190 1.51472 1.78472 1.51432 1.78446 1.77862 1.85651 1.77734 1.85025 1.77599 1.85002 1.84489 1.57487 1.84376 1.57250 1.84256 1.57241 1.57041 1.62408 1.56997 1.62004 1.56949 1.61989 1.61656 1.61582 1.61503 C’ arc Cd Red 514.5 1.52049 1.79880 1.86245 1.57707 1.62790 480.0 1.52283 1.80834 1.87059 1.58000 1.63310 441.6 1.52611 1.82259 1.88253 1.58415 1.64067 457.9465.8472.7 1.52461476.5 1.52395 1.52339486.1 1.52309 1.81596 1.81307 1.52238 1.81070 1.80946 1.87700532.0 1.87458 1.80645 1.87259 1.87153 1.58226 1.51947 1.58141 1.86899 1.58071 1.58034 1.63718 1.79479 1.63564 1.57943 1.63437 1.63370 1.85901 1.63208 1.57580 1.62569 363.8 1.53649 404.7435.8 1.53024 1.52668 1.84208 1.82518 1.89844 1.88467 1.58941 1.58488 1.65064 1.64202 1014.0 1.50731 1.75579 1.82420 1.56152 1.60279 1060.0 1.50669 1.75445 1.82293 1.56088 1.60190 1300.01500.0 1.50370 1.50127 1.74901 1.74554 1.81764 1.81412 1.55796 1.55575 1.59813 1.59550 1550.01970.12325.4 1.50065 1.49495 1.48921 1.74474 1.73843 1.73294 1.81329 1.80657 1.80055 1.55520 1.55032 1.54556 1.59487 1.58958 1.58465 Wavelength Refractive Index of Five Schott Glass Types Five Schott Glass Types Refractive Index of 4ch_MaterialProperties_Final_a.qxd 6/19/2009 4:35 PM Page 4.15 Page 4:35 PM 6/19/2009 4ch_MaterialProperties_Final_a.qxd 4ch_MaterialProperties_Final_a.qxd 6/19/20094:35PMPage4.16

Optical Coatings Material Properties Optical Specifications Gaussian Beam Optics Fundamental Optics 4.16 crown glass transmittancefor10-mm-thick uncoatedoptical External Optical Crown GlassConstants and asasubstratematerialformirrors. is suitableforapplicationsinwhichcomponenttolerancesarefairlyloose fully astheyareinoptical-gradeglassessuchBK7.Opticalcrownglass refraction, transmittance, andhomogeneityarenotcontrolledascare- In opticalcrownglass, alow-indexcommercial-gradeglass, theindexof Optical Crown Glass Transformation Temperature PERCENT EXTERNAL Material Properties Glass Type Designation

TRANSMITTANCE 100 Coefficient ofThermal 20 40 60 80 300 Young’s Modulus Knoop Hardness Softening Point Abbé Constant Specific Heat 0 0 1000 500 400 WAVELENGTH INNANOMETERS Dispersion Expansion Density 71.5 kN/mm 708°C 521°C 93.3# 0.184 cal/g/°C(20°Cto100°C) 2.55 g/cm 542 ( 58.5 B270 n F 4 n C 10 ) = 4 3 2000 0.0089 @ 23°C 7 2 /°C (20°Cto300°C) 3000 Transmission Values for6-mm-thick Sample Refractive IndexofOpticalCrown Glass Note: Transmissioninvisibleregion(includingreflectionloss) Wavelength Fraunhofer Indexof Wavelength 330.0 320.0 310.0 300.0 Blue H Blue Cdarc Hgarc F F’ g 1.52908 1.52960 1.53394 486.1 480.0 435.8 4. .25 ’C r Red H Yellow Cdarc Yellow Naarc C Hearc C’ D 1.52015 d 1.52059 1.52280 656.3 1.52288 643.8 589.0 587.6 600.0 500.0 450.0 400.0 380.0 360.0 350.0 340.0 4. .20 gacGreen Hgarc e 1.52501 546.1 (nm) Region Source Designation Refraction (nm) Material Properties 2 2 www.cvimellesgriot.com r Red arc Blue arc = 91.7% (t Spectral Transmission = 2 mm) 56.6 30.7 91.5 91.4 90.9 90.6 88.8 87.2 83.1 73.6 (%) 7.5 0.3 Fundamental Optics Gaussian Beam Optics Optical Specifications Material Properties Optical Coatings 4.17 Spectral arc Blue www.cvimellesgriot.com 2 Material Properties Material Material Properties (nm) Refraction Designation Source Region 486.1 1.479 F H 514.5546.1587.6 1.477643.8 1.476 1.474 1.472 e d C’ laser Ar Hg arc Green Na arc Cd arc Green Yellow Red Wavelength Index of Fraunhofer Partially processed borosilicate glass borosilicate Partially processed Low-Expansion Borosilicate Glass Low-Expansion Borosilicate ® 2.8 2 2.4 /°C (0°–300°C) 6 @ 25°C dynes/mm 2.0 3 9 4 10 10 820°C 1250°C 66 480 2.23 g/cm 0.20 0.17 cal/g/°C @ 25°C 3.25# 5.98# 1.4 1.0 Density Expansion GTH IN MICROMETERS WAVELEN .6.4.8 Specific Heat Melting Point Abbé Constant Poisson’s Ratio Poisson’s Softening Point Knoop Hardness Young’s Modulus Young’s .2

60 20 80 40

Coefficient of Thermal C S E MITTAN 100 TRAN

C ENT EXTERNAL ENT PER contains more striae and bubbles than optical glasses such as BK7. contains more striae and External uncoated transmittance for 8-mm-thick glass low-expansion borosilicate Low-Expansion Borosilicate Glass Constants Low-Expansion Borosilicate made by Corning. It is well suited for applications in which high tem- made by Corning. It is or resistance to chemical attack are primary thermal shock, perature, other hand, LEBG is typically less homogeneous On the considerations. and condenser suited to such tasks as mirror substrates, material is ideally This or windows in high-tem- illumination systems, lenses for high-power Because of its low cost and excellent thermal perature environments. flats. it is the standard material used in test plates and optical stability, transmission of LEBG extends into the ultraviolet and well into the The considerably from index of refraction in this material varies infrared. The table. are shown in the accompanying values batch to batch. Typical Low-Expansion Borosilicate Glass Borosilicate Low-Expansion low-expansion borosilicate glass (LEBG) is Pyrex most well-known The 4ch_MaterialProperties_Final_a.qxd 6/19/2009 4:35 PM Page 4.17 Page 4:35 PM 6/19/2009 4ch_MaterialProperties_Final_a.qxd 4ch_MaterialProperties_Final_a.qxd 6/19/20094:35PMPage4.18

Optical Coatings Material Properties Optical Specifications Gaussian Beam Optics Fundamental Optics 4.18 ZERODUR Comparison ofthermalexpansioncoefficients of ZERODUR ficient ofthermalexpansionand/orexcellentshockresistance. Many opticalapplicationsrequireasubstratematerialwithnear-zero coef- ZERODUR range of80.15 batch tobatch,withtheroomtemperatureexpansioncoefficientin perature foratypicalsample. The actualperformancevaries veryslightly, The figurebelowshowsthevariation ofexpansioncoefficientwithtem- coefficient ofthecombinationisalmostzeroatusefultemperatures. cient ofexpansionatroomtemperature. The overalllinearthermalexpansion ficient ofthermalexpansion.The crystallinephasehasanegativecoeffi- Typical ofamorphoussubstances, thevitreousphasehasapositivecoef- the refractiveindicesoftwophasesarealmostidentical. eter, andZERODURappearsreasonablytransparenttotheeyebecause to thecrystallinequartzform.The crystalsaretypicallyonly50nmindiam- manufacture sothatapproximately75%ofthevitreousmaterialisconverted component. This Schottglassissubjectedtospecialthermalcyclingduring materials, hasbothanamorphous(vitreous)componentandacrystalline ZERODUR, whichbelongstotheglass-ceramiccompositeclassof temperature issuchamaterial. space-borne imagingsystems. interferometry, manipulationofmoderatelypowerfullaserbeams, and applications asmultiple-exposureholography, holographicandgeneral range, and,consequently, makes idealmirrorsubstratesforsuchstringent the figure. ZERODUR,ismarkedly superioroveralargetemperature thermal expansioncoefficientsofZERODURandfusedsilicaisshownin in thesignofcoefficientnearroomtemperature. Acomparisonofthe

THERMAL EXPANSION -6

Material Properties COEFFICIENT (X 10 /°K) ® –.8 –.6 –.4 –.2 .2 .4 .6 .8 0 ® with itsverysmallcoefficientofthermalexpansionatroom and fusedsilica #10 TEMPERATURE INDEGREESCENTIRADE -250 ® 46 /ºC. Bydesign,thismaterialexhibitsachange 10-00 -50 -150 ZERODUR fused silica 50 150 ZERODUR ZERODUR Refractive IndexofZERODUR Wavelength coatings. with metallic l as asubstratefor commonly used ZERODUR Mirror Substrates Do youneed. 486.1 480.0 435.8 643.8 587.6 546.1 656.3 (nm) /20 mirrors ® Maximum Temperature is aregisteredtrademarkofSchottGlassTechnologies, Inc. Coefficient ofThermal ® ® Constants is Young’s Modulus Knoop Hardness Poisson’s Ratio Abbé Constant Specific Heat Dispersion Expansion ne fRfato Fraunhofer Designation Index ofRefraction Density 1.5491 1.5497 1.5544 1.5399 1.5424 1.5447 1.5394 ® 9.1# ( 66 600°C (20°–300°C) 0.058 0.196 cal/g/°C 0.24 2.53 g/cm 620 n F 4 n 10 C 0.10# Material Properties ) 9 = 3 dynes/mm 0.00967 www.cvimellesgriot.com @ 25ºC 10 4 6 /°C 2 C’ F’ C g d e F Fundamental Optics Gaussian Beam Optics Optical Specifications Material Properties Optical Coatings 6 4 4.19 m 10 Index of 1.46681 1.46324 1.45856 1.45646 # Refraction 5 ≤ n m, and 2.72m /°C (0°C to 200°C) www.cvimellesgriot.com 6 4 Material Properties Material 10 m, 2.2m Material Properties 8 ppm (weight). 0.15 mm typical according to an OH content of ≤ Very weak absorption band Very arouns occur at wavelengths 1.39m <8 ppm 590 0.58# striations guaranteed total D 0 ≤ Striations three dimensions free of In all OH content Bubble class Knoop Hardness Granular Structure None Index Homogeneity In all three dimensions Optical Homogeneity Spectral Transmittance Spectral (nm) Maximum bubble diameter 435.8 486.1 587.6 656.3 Wavelength Thermal Expansion Coefficient Refractive Index of Infrasil 302 Infrasil 302 Constants 4.0 1.0 3.0 0.30 WAVELENGTH IN MICROMETERS WAVELENGTH 0.25 0.35 2.0 m) because it does not exhibit the strong OH absorption m) because it does not m

0.20

80 40 60 20

100 TRANSMITTANCE PERCENT EXTERNAL PERCENT External transmittance for 10-mm-thick uncoated Infrasil 302 Infrasil 302 quartz glass made by fusing natural Infrasil 302 is an optical-quality oven. It combines excellent physical prop- quartz crystals in an electric especially in the near infrared characteristics, erties with excellent optical region (1 to 3 bands typical of synthetic fused silica. bands typical of synthetic in the primary functional direction. Weak Infrasil 302 is homogeneous optical are parallel to the major faces and do not affect if any, striations, performance. 4ch_MaterialProperties_Final_a.qxd 6/19/2009 4:35 PM Page 4.19 Page 4:35 PM 6/19/2009 4ch_MaterialProperties_Final_a.qxd 4ch_MaterialProperties_Final_a.qxd 6/19/20094:35PMPage4.20

Optical Coatings Material Properties Optical Specifications Gaussian Beam Optics Fundamental Optics throughout theentirevisiblespectrum. total transmissionofasapphirecomponentcanbekept above98% magnesium fluorideisdepositedonsapphireandoptimizedfor550nm, almost anidealsingle-layerantireflectioncoating.Whenasinglelayerof face reflections. The highindexofsapphiremakes magnesiumfluoride The transmissionofsapphireislimitedprimarilybylossescausedsur- traveling perpendiculartoit. in indexis0.008betweenlighttravelingalongtheopticaxisand difference inindexofrefractionorthogonaldirections. The difference c-axis relative nent madefromsapphiredependontheorientationofopticaxisor and physicalproperties. The exactcharacteristicsofanopticalcompo- onal crystallinestructure, sapphireexhibitsanisotropyinmanyoptical 4.20 transmittancefor1-mm-thickuncoatedsapphireExternal Sapphire issingle-crystalaluminumoxide(Al can easilybeheatedtopreventcondensation. cooled byforcedairorothermethods. Conversely, sapphirewindows thermal conductivityofsapphire, thinwindowscanbeveryeffectively very closetotheirtransmissionlimits. Becauseoftheexceptionallyhigh other glasstypes, andthereforeareusefulevenatwavelengths thatare sapphire windowscansafelybemademuchthinnerthanof uum ultraviolet)to6m Sapphire exhibitshighinternaltransmittancealltheway from150nm(vac- hydrogen fluoridefailstoattacksapphireattemperaturesbelow300ºC. peratures, sapphirecanbecleanedwithimpunity. For example, even inert andinsolubleinalmosteverythingexceptathighlyelevated tem- stances (suchasdiamondorboronnitride)otherthanitself. Chemically extreme surfacehardness, sapphirecanbescratchedbyonlyafewsub- Sapphire isasuperiorwindowmaterialinmanyways. Becauseofits Sapphire

PERCENT EXTERNAL Material Properties

TRANSMITTANCE 100 20 40 60 80 .1 to theelementsurface. Sapphireexhibitsbirefringence, a 2. 51.0 .5 .3 .2 WAVELENGTH INMICROMETERS m (middleinfrared).Becauseofitsgreatstrength, 2 O 3 ). Becauseofitshexag- 31.5 8 * Sapphireisanisotropicandmanyofitspropertiesrequiretensordescription. Sapphire Constants Refractive IndexofSapphire Wavelength These valuesareaveragesovermanydirections. 2000.0 1550.0 8. .73 1.76711 1.77729 1.78823 1.82411 1.77533 1.78573 1.79691 1.83359 488.0 404.7 351.1 265.2 632.8 546.1 532.0 514.5 (nm) Coefficient ofThermal Dispersion Constants Dispersion Constants (Extraordinary Ray) Young’s Modulus Softening Point Mohs Hardness Poisson’s Ratio (Ordinary Ray) Specific Heat Expansion ne fRfato IndexofRefraction Index ofRefraction Density Ordinary Ray(n 1.73769 1.74618 1.76590 1.77071 1.77170 1.77304 3.7# 3.98 g/cm 7.7# 4 0.18 cal/g/ºC@25°C 9 B 1800°C C C B C C C B B C B B 3 2 1 3 2 1 3 2 1 3 2 1 O 0.02 ======ExtraordinaryRay(n ) 6.5927379 0.55069141 1.5039759 5.3414021 0.65054713 1.4313493 402.8951 0.01479943 0.00548026 325.0178 0.01423827 0.00527993 10 10 4 10 Material Properties 3 6 dynes/mm @ 25ºC /ºC (0°–500°C) www.cvimellesgriot.com 1.72993 1.73838 1.75787 1.76258 1.76355 1.76486 2 E ) Fundamental Optics Gaussian Beam Optics Optical Specifications Material Properties Optical Coatings 4.21 /°C /°C 6 6 3 6 2.425 2.420 2.414 2.410 2.409 2.400 2.400 2.400 2.390 2.385 2.380 2.370 2.360 2.350 2.340 2.330 2.320 2.310 m 4 4 4 m 10 10 10 61# 0.0004/cm 1520°C 112 5.27 g/cm 55.2 Mpa 67.2 Gpa 0.5 Mpa/m 7.6# 0.5–22 <3# www.cvimellesgriot.com m m mm mm Material Properties Material m) Refraction m 6.24 7.50 8.66 9.50 9.72 ( 10.60 11.00 11.04 12.50 13.02 13.50 15.00 16.00 16.90 17.80 18.60 19.30 20.00 Material Properties Density Wavelength Index of Melting Point Knoop Hardness Young’s Modulus Young’s Rupture Modulus Rupture Fracture Toughness Fracture Transmission Range Transmission 2.590 2.461 2.458 2.454 2.449 2.446 2.446 2.444 2.442 2.441 2.440 2.439 2.438 2.436 2.435 2.432 2.430 2.426 Temperature Coefficient of Temperature Refractive Index @ 10.6 Refractive Thermal Expansion Coefficient Bulk Absorption Coefficient @ 10 Bulk Absorption Coefficient m) Refraction m 0.63 1.40 1.50 1.66 1.82 2.05 2.06 2.15 2.44 2.50 2.58 2.75 3.00 3.42 3.50 4.36 5.00 6.00 ( Refractive Index Inhomogeneity @ 633 nm Index Inhomogeneity Refractive Wavelength Index of Zinc Selenide Constants Refractive Index of Zinc Selenide Se gas 30 2 73 GTH IN MICROMETERS WAVELEN laser optics. .5 .7 1 2 5 10 20 2 .3

80 60 40 20

C S E MITTAN 100 TRAN

C ENT EXTERNAL ENT PER External transmittance for 10-mm-thick uncoated zinc selenide and zinc vapor. It has a remarkably wide transmission range and is used It has a remarkably wide transmission range and and zinc vapor. extensively in CO Zinc Selenide sheets by synthesis from H ZnSe is produced as microcrystalline 4ch_MaterialProperties_Final_a.qxd 6/19/2009 4:35 PM Page 4.21 Page 4:35 PM 6/19/2009 4ch_MaterialProperties_Final_a.qxd 4ch_MaterialProperties_Final_a.qxd 6/19/20094:35PMPage4.22

Optical Coatings Material Properties Optical Specifications Gaussian Beam Optics Fundamental Optics makes itunsuitableforCO and lowdensity. frequently 4.22 windows inthe1.5–8mregion.The strongabsorptionbandat9 Silicon iscommonlyusedassubstratematerialforinfraredreflectorsand Silicon External transmittancefor5-mm-thickuncoatedsilicon External

PERCENT EXTERNAL Material Properties

TRANSMITTANCE 100 20 40 60 80 used forlasermirrorsbecauseofitshighthermalconductivity .7 03 50 30 10 5 3 2 1 WAVELENGTH INMICROMETERS 2 laser transmissionapplications, butitis 7 20 70 m Refractive IndexofSilicon Silicon Constants aeeghIndexof Wavelength ( 6.00 5.00 4.36 3.50 3.42 3.00 2.75 2.58 2.50 2.44 2.15 2.06 2.05 1.82 1.66 1.50 1.40 0.63 m )Refraction m) Thermal ExpansionCoefficient Refractive [email protected] Temperature Coefficientof 3.419 3.420 3.422 3.427 3.428 3.431 3.434 3.436 3.440 3.470 3.470 3.490 3.450 3.460 3.470 3.480 3.490 3.920 Transmission Range Young’s Modulus Knoop Hardness Melting Point Density aeeghIndexof Wavelength 20.00 19.30 18.60 17.80 16.90 16.00 15.00 13.50 13.02 12.50 11.04 11.00 10.60 ( 9.72 9.50 8.66 7.50 6.24 m m )Refraction m) Material Properties m www.cvimellesgriot.com 1100 2.33 g/cm 1417°C 4.50# 131 Gpa 1.5–7 160# m 10 10 m 4 4 3 3.416 3.416 3.416 3.416 3.416 3.416 3.416 3.416 3.416 3.416 3.416 3.416 3.416 3.416 3.416 3.416 3.417 3.419 6 6 /°C /°C Fundamental Optics Gaussian Beam Optics Optical Specifications Material Properties Optical Coatings 4.23 /°C /°C 3 6 4.010 4.010 4.007 4.006 4.006 4.006 4.006 4.006 4.000 4.000 4.000 4.000 4.000 4.000 4.000 4.000 4.000 4.000 6 4 4 m 10 10 m 277# 0.035/cm 973°C 692 5.323 g/cm 2–23 102.6 Gpa 5.7# www.cvimellesgriot.com m m Material Properties Material m) Refraction mm mm m 6.24 7.50 8.66 9.50 9.72 ( 10.60 11.00 11.04 12.50 13.02 13.50 15.00 16.00 16.90 17.80 18.60 19.30 20.00 Material Properties Wavelength Index of Density Melting Point Knoop Hardness Young’s Modulus Young’s Transmission Range Transmission 5.390 4.340 4.350 4.330 4.290 4.250 4.240 4.240 4.070 4.220 4.060 4.053 4.054 4.037 4.036 4.023 4.018 4.014 Temperature Coefficient of Temperature Refractive Index @ 10.6 Refractive Thermal Expansion Coefficient Bulk Absorption Coefficient @ 10 Bulk Absorption Coefficient m) Refraction m 0.63 1.40 1.50 1.66 1.82 2.05 2.06 2.15 2.44 2.50 2.58 2.75 3.00 3.42 3.50 4.36 5.00 6.00 ( Wavelength Index of Germanium Constants Refractive Index of Germanium 30 laser applications. 2 73 GTH IN MICROMETERS WAVELEN .5 .7 1 2 5 10 20 .3

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C ENT EXTERNAL ENT PER m wavelength region. It is an ideal substrate material for lenses, region. It is an ideal m wavelength m External transmittance for 10-mm-thick uncoated germanium Germanium to used in imaging systems working in the 2 Germanium is commonly 12 in low-power cw and CO windows and mirrors 4ch_MaterialProperties_Final_a.qxd 6/19/2009 4:35 PM Page 4.23 Page 4:35 PM 6/19/2009 4ch_MaterialProperties_Final_a.qxd 4ch_MaterialProperties_Final_a.qxd 6/19/20094:35PMPage4.24

Optical Coatings Material Properties Optical Specifications Gaussian Beam Optics Fundamental Optics 4.24 Material Properties Overview (LEBG) borosilic Low-expansion Crystal Quartz Suprasil 1 Germanium Silic Fluoride Calc Infrasil 302 N-BK7 BK7 Sapphire SF11 (UVGSFS) Fused Silic Synthetic UV-Grade N-BaK1 BaK1 ZERODUR Calc F2 LaSFN9 Zinc Glass Optic Fluoride Magnesium Material on Selenide ium ite al Crown Material Properties ate glass ® a 0.1 CRYSTAL QUARTZ MAGNESIUM FLUORIDE Usable Transmission Range SUPRASIL INFRASIL PIA CROWN OPTICAL WAVELENGTHS INm UVGSFS . 1.0 0.5 ZERODUR CALCITE CALCIUM FLUORIDE SAPPHIRE BaK1 LEBG LaSFN9 BK7 F2 SF11 ® ICSELENIDE ZINC SILICON GERMANIUM . 10.0 5.0 Refrac Index of 0.63 m 1.55@ 0.27 m 1.50@ 10.6 m 4.00@ 10.6 m 3.42@ 1.399 @ 0.55 m 1.55@ 0.63 m 1.46@ 0.55 m 1.66@ 0.55 m 0.55 0.55 0.55 0.55 0.55 10.6 0.27 0.55 0.55 0.55 1.52 @ 1.79 @ 1.46 @ 1.57 @ 1.62 @ 1.8 2.40 @ 1.41 @ 1.48 1.77 @ 1.52 @ 5 m 6 @ m m m m m m m m m m m tion @ m m m m m m m m m m c High-refrac c Material providesexc Exc a Material representsagoodc visible andIR,haslowabsorptionintheredendofspe Zinc c High-refrac exc Exc c vac Tetragonal positivebirefringentc for high-temperaturewindows,mirrorsubstrates,andc Exc Exc window material c This lowertoleranc and mirrorsubstrates This popularUVexc Naturally occuringnegativeuniaxialc threshold waveplatesandBrewsterwindows Uniaxial birefringentsinglec and lowfluoresc Type offusedsilic c Higher refrac mirrors, andfilters Lighter weightthantheotherIRmaterials,Siisoftenusedinlenses, Highly homogeneousglass-c windows andlenses Low OHc birefringenc applic of thermalexpansionisidealformirrorsubstratesstringent urvature harac urvature harac ritic cceptable mec urvature thanZnSe ellent thermalstability,lowc ellent mec ellent all-aroundlensmaterial,buthasweakerc ellent all-aroundlensmaterialprovidesbroadtransmissionwith uum UVapplic ellent mec selenideismostpopularfortransmissiveIRopti al applic teristic teristic ations ontent fusedquartzrec tive-index flintglassprovidesmorepowerwithless tive-index flintglassprovidesmorepowerwithless e makesthismaterialsuitableforpolarizingprisms ations s s thanBK7 hanic hanic tive indexthanZnSeprovidesmorepowerwithless hanic enc ations forwindows,polarizers,andlenses a withhighpurity,multipleaxishomogeneity, e glassc al al andthermalc imer lasermaterialisusedforwindows,lenses, e al ellent UVtransmissionandsuperiorme c harac c harac an beusedasamirrorsubstrateorinnon- teristic ompromise betweenhigherindexand rystal usedprimarilyonhighdamage eramic teristic Features ost, andhomogeneitymakesLEBGuseful rystal materialpreferredforhigh ommended forNIRhighenergy s harac withnear-zeroc s rystal withpronounc teristic Material Properties www.cvimellesgriot.com s makeitasuperior hemic c ondenser lenses s; transmits oeffic al ient ed c hanic c trum al