OpticsTalk: The Strengths & Applications of Various Freeform Surface Representations

  • 20 July 2020
  • 5 replies

Userlevel 4
Badge +2

Here's the discussion space for the OpticsTalk: The Strengths & Applications of Various Freeform Surface Representations hosted by Zemax Computational Physicist, Radu Miron.

Let's join Radu to learn more and discuss about Freeform surfaces in Zemax Products

Stay tuned on this forum thread for updates and discussion after the talk and check out our other OpticsTalks!

5 replies

Userlevel 4
Badge +2

Thank you very much for attending the OpticsTalks and participating to the discussion.

I also want to thank Radu for the great presentation!

Here are the articles I mentionned during the talk based on the questions we got:


who's afraid of freeform optics? Freeform optics in OpticStudio How to design progressive lenses convert chebychev to extended polynomial Using TrueFreeform
https://support.zemax.com/hc/en-us/articles/1500005577362-Who-s-afraid-of-freeform-optics-webinar https://support.zemax.com/hc/en-us/articles/1500005576322-Freeform-optics-in-OpticStudio https://support.zemax.com/hc/en-us/articles/1500005575622-How-to-design-progressive-lenses https://support.zemax.com/hc/en-us/articles/1500005489981-How-to-create-a-ZOS-API-User-Extension-to-convert-from-Chebyshev-to-Extended-polynomial https://support.zemax.com/hc/en-us/articles/1500005490761-Using-the-TrueFreeForm-surface-for-grid-based-freeform-optimization


I also digged some articles about freeform manufacturing:


tolerancing with OS, zernike tolerancing with OS, grid sag micro optics freeforms manufacturing Using state-of-the-art replication processes, Spectrum Scientific offers a cost-effective method for the volume manufacturing of freeform mirrors. Features include: aluminium or glass substrates; ellipse and paraboloid profiles; size 0.5 inch to 6.0 inch diameter; typical surface figure down to λ/8 (λ/14 possible);  surface roughness down to 3.5Å; and gold or aluminium coating.
How to use TEZI to tolerance for manufacturing-related surface sag error How to add radial ripple to a sequential surface using the ZOS-API https://www.electrooptics.com/white-paper/production-precision-optics-using-laser-micro-machining https://www.electrooptics.com/product/focus/reflecting-mirrors



I hope this will prove usefull. 

One of my colleague as worked on a series of 4 articles on how to model MSF using the grid sag surface.

We started the discussion on some interesting topics, here are some of them. Feel free to continue the discussion in this forum thread:

  • Which surface type do you preferably use when designing freeform optics? Why?  
  • Why do you use freeform optics for?    
  • Are there any reasons why you are not using freeform optics?
  • Which surface should you choose for your optimization?
  • How to tolerance freeform optics?




Userlevel 4
Badge +2

Here is the list of references that Radu used during his presentation:

•[1] Kevin P. Thompson and Jannick P. Rolland, 'Freeform Optical Surfaces: A Revolution in Imaging Optical Design,' Optics & Photonics News 23(6), 30-35 (2012)

•[2] Jingfei Ye, Lu Chen, Xinhua Li, Qun Yuan, Zhishan Gao, 'Review of optical freeform surface representation technique and its application,' Opt. Eng. 56(11) 110901 (11 November 2017)

•[3] H. Gross, A. Brömel, M. Beier, R. Steinkopf, J. Hartung, Y. Zhong, M. Oleszko, D. Ochse, 'Overview on surface representations for freeform surfaces,' Proc. SPIE 9626, Optical Systems Design 2015: Optical Design and Engineering VI, 96260U (23 September 2015);

•[4] Nick Takaki, Aaron Bauer, and Jannick P. Rolland, 'On-the-fly surface manufacturability constraints for freeform optical design enabled by orthogonal polynomials,' Opt. Express 27, 6129-6146 (2019)

•[5] Li Xu, Kexin Chen, Qingsheng He, and Guofan Jin, 'Design of freeform mirrors in Czerny-Turner spectrometers to suppress astigmatism,' Appl. Opt. 48, 2871-2879 (2009)

•[6] Jui-Wen Pan, Chiang Che-Wen, Kuan-Da Huang, and Chung-Yu Wu, 'Demonstration of a broad band spectral head-mounted display with freeform mirrors,' Opt. Express 22, 12785-12798 (2014)

•[7] Mao Shanshan, Li Yanqiu, Liu Ke, Liu Lihui, Zheng Meng, Yan Xu. Optical design of high numerical aperture extreme ultraviolet lithography objective with freeform surfaces[j]. Infrared and Laser Engineering, 2019, 48(8): 814002-0814002(7)

•[8] G. W. Forbes, 'Shape specification for axially symmetric optical surfaces,' Opt. Express 15, 5218-5226 (2007)

•[9] A. Brömel, H. Gross, D. Ochse, U. Lippmann, C. Ma, Y. Zhong, M. Oleszko, 'Performance comparison of polynomial representations for optimizing optical freeform systems,' Proc. SPIE 9626, Optical Systems Design 2015: Optical Design and Engineering VI, 96260W (23 September 2015)

•[10] The Chebyshev Polynomials, by Theodore J. Rivlin (1974)

•[11] G. W. Forbes, 'Characterizing the shape of freeform optics,' Opt. Express 20, 2483-2499 (2012)

•[12] G. W. Forbes, “Manufacturability estimates for optical aspheres,” Opt. Express 19(10), 9923–9941 (2011)

•[13] Nick Takaki, Jonathan C. Papa, Aaron Bauer, and Jannick P. Rolland, 'Off-axis conics as base surfaces for freeform optics enable null testability,' Opt. Express 28, 10859-10872 (2020)

•[14] Isaac Trumper, Maham Aftab, and Dae Wook Kim, 'Freeform surface selection based on parametric fitness function using modal wavefront fitting,' Opt. Express 27, 6815-6831 (2019)

•[15] W. Swantner and Weng W. Chow, 'Gram–Schmidt orthonormalization of Zernike polynomials for general aperture shapes,' Appl. Opt. 33, 1832-1837 (1994)

Is a recorded version of Radu’s presentation available somewhere?  When I click on the OpticsTalks link above, I cannot get to its destination.

If the presentation has not been recorded, are some slides perhaps available?

Userlevel 6
Badge +3

Was there a bottom line to this presentation, some matrix of application versus surface type?