Optical Design with Zemax

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1 Optical Design with Zemax Lecture 9: Advanced handling Herbert Gross Sommer term

2 2 Preliminary Schedule Introduction Properties of optical systems I Properties of optical systems II Aberrations I Introduction, Zemax interface, menues, file handling, preferences, Editors, updates, windows, coordinates, System description, Component reversal, system insertion, scaling, 3D geometry, aperture, field, wavelength Diameters, stop and pupil, vignetting, Layouts, Materials, Glass catalogs, Raytrace, Ray fans and sampling, Footprints Types of surfaces, Aspheres, Gratings and diffractive surfaces, Gradient media, Cardinal elements, Lens properties, Imaging, magnification, paraxial approximation and modelling Representation of geometrical aberrations, Spot diagram, Transverse aberration diagrams, Aberration expansions, Primary aberrations, Aberrations II Wave aberrations, Zernike polynomials Aberrations III Point spread function, Optical transfer function Optimization I Principles of nonlinear optimization, Optimization in optical design, Global optimization methods, Solves and pickups, variables, Sensitivity of variables in optical systems Optimization II Systematic methods and optimization process, Starting points, Optimization in Zemax Advanced handling I Telecentricity, infinity object distance and afocal image, Local/global coordinates, Add fold mirror, Scale system, Make double pass, Vignetting, Diameter types, Ray aiming, Material index fit Advanced handling II Report graphics, Universal plot, Slider, Visual optimization, IO of data, Multiconfiguration, Fiber coupling, Macro language, Lens catalogs Imaging Fundamentals of Fourier optics, Physical optical image formation, Imaging in Zemax Correction I Correction II Symmetry principle, Lens bending, Correcting spherical aberration, Coma, stop position, Astigmatism, Field flattening, Chromatical correction, Retrofocus and telephoto setup, Design method Field lenses, Stop position influence, Aspheres and higher orders, Principles of glass selection, Sensitivity of a system correction

3 3 Contents 1. Miscellaneous 2. Vignetting, diameter types, ray aiming 3. Material index fit 4. Lens catalogs

4 4 Special Infinity Cases Object in infinity - incoming marginal ray parallel to axis - first distance infinity - off-axis field only as angle - no initial NA possible Image in infinity - outgoing marginal ray ideally parallel to axis - explicit declaration: afocal image space - geometrical aberrations as angles - wave aberration reference is plane wave - definition of Airy diameter in mrad Entrance pupil in infinity - incoming chief ray parallel to axis - explicit declaration: telecentric object space Exit pupil in infinity - outgoing chief ray ideally parallel to axis

5 The Special Infinity Cases Simple case: - object, image and pupils are lying in a finite distance - non-telecentric relay systems Special case 1: - object at infinity - object sided afocal - example: camera lens for distant objects Special case 2: - image at infinity - image sided afocal - example: eyepiece Special case 3: - exit pupil at infinity - image side telecentric - example: camera lens for metrology Special case 4: - exit pupil at infinity - image sided telecentric - example: old fashion lithographic lens 5

6 The Special Infinity Cases Very special: combination of above cases Examples: - both sided telecentric: 4f-system, lithographic lens - both sided afocal: afocal zoom - object sided telecentric, image sided afocal: microscopic lens Notice: telecentricity and afocality can not be combined on the same side of a system

7 7 Cardinal Elements in Zemax Cardinal elements of a selected index range (lens or group)

8 Quick Focus Option In the menue TOOLS DESIGN QUICK FOCUS we have the opportunity to adjust the image location according to the criteria 1. Spot diameter 2. Wavefront rms 3.

8 8 Quick Focus Option In the menue TOOLS DESIGN QUICK FOCUS we have the opportunity to adjust the image location according to the criteria 1. Spot diameter 2. Wavefront rms 3. Angle radius IN principle, this option is a simplified optimization Example: find the best image plane of a single lens Spot before and after performing the optimal focussing

9 9 Quick Adjust Option In the menue TOOLS DESIGN QUICK ADJUST we have the opportunity to adjust 1. one thickness 2. one radius similar to the quick focus function some where in the system Special application: adjust the air distance before a collimation lens to get the best collimation As criteria, wavefroint, spot diameter of angular radius ar possible Example: Move a lens in between a system to focus the image Spots before and aftre thew adjustment

10 10 System changes Useful commands for system changes: 1. Scaling (e.g. patents) 2. Insert system with other system file File - Insert Lens 2. Reverse system

11 11 3D Geometry Auxiliary menus: 1. Tilt/Decenter element 2. Folding mirror

12 12 3D Geometry Local tilt and decenter of a surface 1. no direct visibility in lens editor only + near surface index 2. input in surface properties 3. with effect on following system surfaces

13 Aperture data in Zemax Different possible options for specification of the aperture in Zemax: 1. Entrance pupil diameter 2. Image space F# 3. Object space NA 4. Paraxial working F# 5. Object cone angle 6. Floating by stop size Stop location: 1. Fixes the chief ray intersection point 2. input not necessary for telecentric object space 3. is used for aperture determination in case of aiming Special cases: 1. Object in infinity (NA, cone angle input impossible) 2. Image in infinity (afocal) 3. Object space telecentric

14 14 Diameters in Zemax There are several different types of diameters in Zemax: 1. Surface stop - defines the axis intersection of the chief ray - usually no influence on aperture size - only one stop in the system - is indicated in the Lens Data Editor by STO - if the initial aperture is defined, the size of the stop semi-diameter is determined by marginal raytrace

15 15 Diameters in Zemax 2. Userdefined diameter at a surface in the Lens Data Editor (U) - serves also as drawing size in the layout (for nice layouts) - if the diameter in the stop plane is fixed, the initial aperture can be computed automatically by General / Aperture Type / Float by Stop Size This corresponds to a ray aiming 3. Individual diameter of perhaps complicated shape at every surface ( apertures ) - no impact on the drawing - is indicated in the Lens Data Editor by a star - the drawing of vignetted rays can by switched on/off

16 Diameters and stop sizes 4. Individual aperture sizes for every field point can be set by the vignetting factors of the Field menu - real diameters at surfaces must be set - reduces light cones are drawn in the layout VDX, VDY: relative decenter of light cone in x, y VCX, VCY: compressian factors in x, y VAN: azimuthal rotation angle of light cone - If limiting diameters are set in the system, the corresponding factors can be calculated by the Set Vig command 16

17 17 Diameters in Zemax In the Tools-menue, the diameters and apertures can be converted automatically

18 18 Ray Aiming Userdefined diameter at a surface in the Lens Data Editor (U) - serves also as drawing size in the layout (for nice layouts) - if the diameter of the system stop is fixed, the initial aperture can be computed automatically by General / Aperture Type / Float by Stop Size This corresponds to a ray aiming on the rim of the stop surface. The aperture values in the PRESCRIPTION DATA list then changes with the diameter A more general aiming and determination of the opening for all predefined diameters is not possible in Zemax

accuracy, especially at wavelengths and temperatures with sparse input data and

19 Material Index Fit choice of 4 dispersion formula after fit: - pv and rms of approximation visible - no individual errors seen check results for suitable accuracy, especially at wavelengths and temperatures with sparse input data and at intervall edges add to catalog enter additional data Save catalog Ref.: B. Böhme 19

20 20 Material Index Fit Establishing a special own material Select menue: Tools / Catalogs / Glass catalogs Options: 1. Fit index data 2. Fit melt data Input of data for wavelengths and indices It is possible to establish own material catalogs with additional glasses as an individual library

21 21 Material Index Fit Melt data: - for small differences of real materials - no advantage for new materials Menue option: Glass Fitting Tool don t works (data input?)

dat with two columns: wavelength in mm and index Choice of 4 different dispersion formulas

22 22 Material Index Fit Menue: Fit Index Data Input of data: 2 options: 1. explicite entering wavelengths and indices 2. load file xxx.dat with two columns: wavelength in mm and index Choice of 4 different dispersion formulas After fit: - pv and rms of approximation visible - no individual errors seen - new material can be added to catalog - data input can be saved to file

23 Lens Catalogs Lens catalogs: Data of commercial lens vendors Searching machine for one vendor Componenets can be loaded or inserted Preview and data prescription possible Special code of components in brackets according to search criteria 23

24 Lens Catalogs Some system with more than one lens available Sometimes: - aspherical constants wrong - hidden data with diameters, wavelengths,... - problems with old glasses Data stored in binary.zmf format Search over all catalogs not possible Catalogs changes dynamically with every release Private catalog can be generated 24

25 Stock Lens Matching This tool swaps out lenses in a design to the nearest equivalent candidate out of a vendor catalogue It works together with the merit function requirements (with constraints) Aspheric, GRIN and toroidal surfaces not supported; only spherical Works for single lenses and achromates Compensation due to thickness adjustments is optional Reverting a lens to optimize (?) Top results are listed Combination of best single lens substitutions is possible. Overall optimization with nonlinear interaction? Ref.: D. Lokanathan

26 Stock Lens Matching Selectioin of some vendors by CNTR SHIFT marking Ref.: D. Lokanathan

27 Stock Lens Matching Output Ref.: D. Lokanathan

Lens Design I. Lecture 5: Advanced handling I Herbert Gross. Summer term

Lens Design I. Lecture 5: Advanced handling I Herbert Gross. Summer term Lens Design I Lecture 5: Advanced handling I 2015-05-11 Herbert Gross Summer term 2015 www.iap.uni-jena.de 2 Preliminary Schedule 1 13.04. Basics 2 20.04. Properties of optical systrems I 3 27.05. Properties