United States Patent 1191 1111 3,720,877 Zarowin 1451March 13, 1973

1541 METAL VAPOR DISCHARGE TUBE OTH ER PU BLIC ATIONS USING METAL AND SEMI-METAL Fraford, “High Peak Power Pulsed l0p,CO Laser" COMPOUNDS IN A DISCHARGE TUBE 12/28/65, pg. 384-385, Physics Letters, Vol. 20, No. [751 Inventor: Charles B. Zarowin, Tarrytown, 4. N.Y. Carfare, “Continuous Operation of a Long Lived CO Laser Tube”, 3/68, pg. 102—103, IEEE JQE. [7.3] Assignee: International Business Machines Corporation, Armonk, N.Y. Primary Examiner-Benjamin A. Borchelt Assistant Examiner-—N. Moskowitz [22] Filed: Sept. 25, 1970 Attorney-Hanifin and Jancin and John J. Goodwin [21] Appl. No.: 75,589 [57] ABSTRACT A metal vapor discharge tube device including a 152] U.S. Cl ...... 330/4.3, 33l/94.5 [51] Int. Cl...... II01s 3/09 discharge tube and means for introducing a metal or [53] Field of Search ...... 33l/94.5; 330/43 semi-metal into the discharge tube without auxiliary heating. The metal or semi-metal is introduced as a References Cited compound of a metal or semi'metal and a non-metal 156] lic radical having a vapor pressure greater than one UNITED STATES PATENTS torr at the temperature of the discharge tube (which for most discharge tubes can be as high as about 300° 3,424,720 12/1969 Walter ...... 33 1/945 C). The discharge in the tube causes the decomposi 3,464,028 8/1969 Moeller tion of the compound, thereby releasing the metal or 3,411,105 11/1968 Patel ...... semi-metal into the discharge for excitation. If desired, 3,411,106 11/1968 Fried] ...... 331/94.5 the excitation can produce lasing and the device may be used as a metal vapor laser. 3 Claims, 1 Drawing Figure

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INVENTOR CHARLES H. ZAROWIN BY 83'“ HM ATTORNEY 3,720,877 1 2 METAL VAPOR DISCHARGE TUBE USING METAL vide sufficient vapor pressure in a discharge tube at AND SEMI-METAL COMPOUNDS IN A practical temperatures. For example, Molybdenum DISCHARGE TUBE (Mo) has a melting point of 2,620° C, Ruthenium (Ru) is l,950° C, Osmium (Os) is 2,500° C and Tungsten (W) is 3,030". Thus, only the low melting point metals BACKGROUND OF THE INVENTION which have sufficient vapor pressure at low tempera 1. Field of the Invention ture can be used in metal vapor lasers. The present in The present invention is in the metal vapor discharge vention provides a way in which metals such as molyb tube and laser technology. denum, ruthenium, osmium, tungsten and other high 2. Prior Art melting point metals and semi-metals can be employed Metal vapor lasers are known in the prior art wherein in the vapor state in metal vapor discharge tubes or pure metal vapor is introduced into the discharge tube lasers without auxiliary heating. by auxiliary heating of the metal. The present invention In the present invention the metal or semi-metal is in isdistinct over the prior art in that a metal or semi troduced into the discharge tube as a compound having metal compound is introduced into the discharge tube a vapor pressure greater than approximately one torr at in a gaseous state without auxiliary heating as a con the temperature of the discharge tube (as high as about sequence of the high vapor pressure of the compound 300°C). Thus at this temperature or above, some of the compared to the pure metal or semi-metal. In the compound is in the vapor or gaseous state. In the discharge tube, the compound decomposes into the 20 discharge tube the discharge provides energy which metal or semi-metal and the non-metallic radical. The causes decomposition of the compound and thereby metal is thus made available for use in the discharge provides the atomic species of the metal available for tube. The present invention therefore permits the use excitation. of high melting point metals or semi-metals in a MOre particularly, consider a compound composed discharge tube whereas in the prior art the use of such 25 of a metal or semi-metal M and a non-metallic radical metals or semi-metals was impossible or impractical X, the compound being represented by MX,,. In the due to the extreme heat required. discharge the following reaction occurs: SUMMARY OF THE INVENTION An object of the present invention is to provide a 30 The reaction is reversible which means the metal or metal vapor discharge tube using metals and semi semi-metal and the non-metallic radical will recombine metals having relatively high melting points. in the tube to form the compound. Thus, there will be a Another object of the present invention is to provide constant decomposition and recombination process oc a metal vapor discharge tube using metals or semi curring in the discharge tube so that metal or semi metals without auxiliary heating through the use of 35 metal molecules will be available in sufficient concen metal or semi-metal compounds having vapor pressures tration for excitation at all times. The excitation and greater than one torr at temperatures up to about consequent relaxation of the metal or semi-metal atoms 300°C. produce the emission oflight (lasing). A further object of the present invention is to pro Referring to the drawing, a schematic representation vide a system and method wherein metal or semi-metal of a discharge tube is shown. The tube 10 may include compounds are introduced into a discharge tube in the re?ectors I2 and 14 at the Brewster angle so that vapor state without auxiliary heating wherein the com emitted light may be coupled out of the tube. Conven pound decomposes into metal and the non‘metallic tional vapor traps l6 and 18 may also be included to radical. 45 maintain the vapor in the desired region. The tube ini Still another object of the present invention is to pro tially contains a rare gas, for example argon, krypton, vide a metal vapor laser wherein metals or semi-metals helium, etc. Electrodes 20 and 22 and power source 32 are introduced into a discharge tube as vapor com pounds. are provided to excite the gas to provide an electrical The foregoing and other objects, features and ad discharge. The electrode regions may also be isolated by vapor traps 24 and 26. The discharge tube shown in vantages of the invention will be apparent from the fol 50 lowing more particular description of a preferred em the drawing is only representative, the present inven tion may be practiced with other known discharge bodiment of the invention, as illustrated in the accom tubes, for example electrodless tubes which employ panying drawing. 1 The drawing is a schematic illustration of an embodi capacitive or inductive excitation. 55 ment of a metal vapor discharge tube according to the A compound of a metal or semi-metal and a non principles of the present invention. metallic radical is contained in vessel 28 which is con Metal vapor lasers are useful devices that have ad nected to tube 10 through a valve 30. The compound in vantages over other type lasers such as rare gas lasers. vessel 28 has a vapor pressure greater than approxi Since electrons are not as tightly bound to metal atoms mately one torr at the temperature of the discharge as to non-metallic atoms, a laser employing a metal tube (approximately 300°C) so that the compound will vapor in the active medium can be brought into the be in the vapor state as a result of the heat produced by excited state using lower energy levels than that the discharge. when valve 30 is opened, the compound required for other type lasers. Heretofore, a pure metal' will enter discharge tube 10 and the discharge will cause excitation of the compound (and in the case of in a solid state was placed in a discharge tube and 65 heated in order to convert some fraction of it into the some compounds, cause ionization) which will cause vapor state in the tube. There are a large number of decomposition. That is, the hot electrons in the metals having melting points that are too high to pro discharge collide with the molecules of the compound 3,720,877 3 4 and cause decomposition. After decomposition the Fluorosilane SiHQF lodosilane SiH3l metal molecules and the non~metallic radical Bromodichlorol'luorosilane SiBrChF molecules will recombine upon collision, however, the Chlorotrifluorosilane SiC 1 F; Dihromochlorol'luorosilane SiBrzClF discharge will continue to cause decomposition and a Dibromosilane V siHzBrz state of equilibrium will be reached and there will be a Dichlorodifluorosilane SiClgF, Di?uorosilane SiHZF, concentration of metal vapor which will be excited into Disilane SiZHS the lasing condition. Disiloxane (SiH;),0 It was previously stated that the compounds that are Fluorotrichlorosilane SiClaF Hexachlorodisilane SIZCIQ employed in the present invention are those consisting Hexafluorodisilane SizFa of a metal or semi~metal and a non-metallic radical Octachlorotrisilane SiQCIB Tetrasilane SiJ'lm having a vapor pressure greater than torr at the operat Tribromo?uorosilane SiBr3F ing temperature of the discharge tube which can be as Tribromosilane SiHBra high as about 300°C. Trichlorosilane SiI-ICla Trifluorosilane SiHFQ Examples of some compounds which may be em Trisilane Si3H8 ployed in the present invention are listed below. Disilazane (SIHQSN Sulfur hexa?uoride SP8 Sulfur dioxide S02 Name Formula Sulfur monochloride S2Cl2 Aluminum bromide AlBr3 Sulfur trioxide (or) SO; Aluminum chloride AlCla Sulfur trioxide (B) SO; Aluminum iodide Alla Sulfur trioxide (7) S03 Antimony tribromide SbBra Thionyl bromide SOBr-z Antimony trichloride SbCla Thionyl chloride SOClz Antimony pentachloride SbCls Tantalum penta?uoride TaFs Antimony triiodide Sbl;l Tellurium tetrachloride TeCl, Antimony pentiodide Sbl5 Tellurium hexafluoride TeF‘, Arsenic tribromide AsBra Titanium tetrachloride TiCl4 Arsenic trichloride AsCla Tungsten hexafluoride WF; Arsenic pental'luoridc AsF5 25 Uranium hexa?uoride UFG Arsenic hydride (arsinc) AsI‘I;l Vanadyl trichloride \(OCI; Arsenic trioxide A520, Zirconium tetrabromidc ZrBr; Beryllium borohydride BeB,H,i Zirconium tetrachloride ZrCl, Beryllium bromide BeBr Zirconium tetraciodide ZrI‘ Beryllium chloride BeClz Beryllium iodide Bel2 Borine carbonyl BHJCO 30 The above list is representative of compounds having Boron tribromide BBrn vapor pressure greater than approximately one torr at Boron trichloride BCI3 300°C. A person having ordinary skill in the art could Boron trifluoride BF“ Dihydrodiborane BzHa look up other compounds using a chemical handbook. Diborane hydrobromide B1BrH5 A very extensive list is provided by Daniel R. Stull in In~ Triborine triamine Bal-laNa Tetrahydrotetraborane 84H“, 35 dustrial and Engineering Chemistry, 39,517 (1947). Tetrahydropentaborane 85H" What has been described is a metal vapor laser Dihydrodecaborane BWHH wherein metals with very high melting points can be Bromine penta?uoride BrF5 Carbon tetrachloride CC] 4 employed whereas heretofore the use of such metals Carbon tetra?uoride CF‘ was impractical or impossible. Carbon dioxide CO2 40 Carbon suboxide C_-,O2 While the invention has been particularly shown and Carbon disul?de CSz described with reference to preferred embodiments Carbon subsul?de C352 Carbon selenosulfide CSSe thereof, it will be understood by those skilled in the art Carbon monoxide CO that the foregoing and other changes in form and Carbonyl chloride COCI, details may be made therein without departing from the Carbonyl selenide COSe 45 Carbonyl sul?de COS spirit and scope of the invention. - Chromium carbonyl Cr(CO)B What is claimed is:' Chromyl chloride Cr0,Cl, Ferric chloride FeCl, l. A metal vapor discharge tube device comprising: Gallium trichloride GaCl, a discharge tube containing a gas, Germanium hydride GeH, means for exciting said gas in said tube to produce an Germanium bromide GeBr, Germanium chloride GeCl, electrical discharge in said tube, said electrical Trichlorogermanc GeHCl? discharge causing said discharge tube to operate at Tetramethylgermanium Ge(CH3)4 Digermane Gc,H, a given temperature, and Trigermane GenHa means for introducing a compound of a metal or Iodine pental'luoride IF5 semi-metal and a non-metallic radical into said Iodine heptafluoride IF, 55 Iron pentaearhonyl Fe(C0), tube in the vapor state, said compound having a Mercuric bromide HgBr, vapor pressure greater than one torr at the operat Mcreuric chloride HgCl2 Mercurie iodide Hgl, ing temperature of said discharge tube during said Molybdenum hexafluoride MoFu discharge, wherein said electrical discharge Nickel carbonyl Ni(CO)‘ decomposes said metal or semi-metal compound Phosphorous tribromide PBr, 60 Phosphorous trichloride PCla into the metal or semi-metal and the non-metallic Phosphorous pentachloride PCI5 radical followed by electron excitation of the Phosphorous thiobromide PSBra Phosphorous thiochloride PSCIJ metal to produce population inversion, wherein Selenium dioxide Se0, ‘ said decomposition occurs without external heat Selenium hexafluoride SeFa ing but is due to the operating temperature of the Selenium oxychloride SeOClz 65 Selenium tetrachloride SeCl, discharge tube. _ Silicon tetra?uoride SiF; 2. A metal vapor discharge tube device according to Bromosilane siHaBr Chlorosilane SIHQCI claim 1 wherein said gas and said metal or semi-metal 3,720,877 5 6 in said discharge tube is excited by said excitation as a vapor,said compound having a vapor pressure means to produce stimulated emission oflight. greater than one torr at the operating temperature 3. A method for introducing a metal or semi-metal of said discharge tube during said discharge, into a discharge tube containing a gas comprising the wherein said electrical discharge causes said com steps of; 5 pound to decompose into the metal or semi-metal producing an electrical discharge in said gas in said and the "On-metallic radical and pr0duces elec discharge tube, said electrical discharge causing PTO" elicitation offhe metal to produce population said discharge tube to have an operating tempera- lnf'erslonv wherem 531d decomposltlon occurs ture, and without external heating but is due to the operat introducing a compound of a metal or semi-metal '0 mg temparaturc onhc dlschal'ge tube and a non-metallic radical into said discharge tube * * * * *

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