Y. Sekman, X. Lu, H. Gross Friedrich Schiller University Jena Institute of Applied Physics Albert-Einstein-Str 15 07745 Jena Lens Design I – Seminar 1 Exercise 1-1: Stair-mirror-setup (Homework) Setup a system with a stair mirror pair, which decenters an incoming collimated ray bundle with 10 mm diameter by 40 mm in the -y direction. The wavelength of the beam is = 632.8 nm. After this pair of mirrors, a decentered main objective lens with focal length f = 200 mm made of BK7 is located 25 mm below the optical axis and focusses the beam. a) Setup the system b) Generate layout drawings in 2D and in 3D. c) Calculate the beam cross section on the second mirror, what is the size of the pattern? d) Determine the optimal final sensor plane location. Calculate the spot of the focused beam. Discuss the shape of this pattern. Exercise 1-2: Symmetrical 4f-system Setup a telecentric 4f-imaging system with two identical plano-convex lenses made of BK7 with thickness d = 10 mm and approximate focal lengths f = 100 mm. The wavelength of the system is = 546.07 nm and the numerical aperture in the object space is NA = 0.2. The object has a diameter of 10 mm. a) If the setup is perfectly symmetrical, determine the layout and the spot diagram of the system. b) Optimize the image location. Why is the spot size improved? c) If the starting aperture is decreased, the system becomes more and more close to diffraction limited. What is the value of the NA to get a diffraction limited system on axis? Take in mind here, that a re-focussing might be necessary due to the lowered spherical aberrations, which depends on the aperture. Exercise 1-3: Apertures, stops and vignetting Load the achromate f = 100mm AAP-100.0-25.4, Melles Griot. Set the entrance pupil diameter to be 20mm. Show the wavefront of the achromate for the field points 0°, 3° and 5° with the following configurations. a) The stop surface is at the rear surface of the achromate b) The stop surface is at the front focal plane of the achromate, without setting vignetting. Use the ‘Cardinal Point Data’ button in Analyze->Reports to find this stop position. c) Set vignetting in the ‘Field Data Editor’ and repeat b). d) Insert a 6mm obscuration at the rear surface and calculate the wavefront, compare the wavefronts with / without ‘set vignetting’. e) Clear all vignetting, then calculate the ray intersection coordinates (REAY) at the rear surface for the marginal rays and the chief ray of field 5° in the merit function editor. Interpret the result. The exercises will be discussed on Thursday, 19.04.2018, at 10.15 am in the Computer Pool of the ACP. Please solve task 1-1 on your own and save your intermediate results. .