Combining freeform optics and curved detectors for wide field imaging: a polynomial approach over squared aperture.

In the recent years a significant progress was achieved in the field of design and fabrication of optical systems based on freeform optical surfaces. They provide a possibility to build fast, wide-angle and high-resolution systems, which are very compact and free of obscuration. However, the field of freeform surfaces design techniques still remains underexplored. In the present paper we use the mathematical apparatus of orthogonal polynomials defined over a square aperture, which was developed before for the tasks of wavefront reconstruction, to describe shape of a mirror surface. Two cases, namely Legendre polynomials and generalization of the Zernike polynomials on a square, are considered. The potential advantages of these polynomials sets are demonstrated on example of a three-mirror unobscured telescope with F/# = 2.5 and FoV = 7.2x7.2°. In addition, we discuss possibility of use of curved detectors in such a design.

[1]  Juan C. Miñano,et al.  Optical design through optimization for rectangular apertures using freeform orthogonal polynomials: a case study , 2016 .

[2]  Wei Wang,et al.  Easy-aligned off-axis three-mirror system with wide field of view using freeform surface based on integration of primary and tertiary mirror. , 2014, Applied optics.

[3]  P. Peumans,et al.  Curving monolithic silicon for nonplanar focal plane array applications , 2008 .

[4]  Peter Brewer,et al.  Highly curved image sensors: a practical approach for improved optical performance , 2017, Optics express.

[5]  Michael P Lesser,et al.  Focal Plane Technologies for LSST , 2002, SPIE Astronomical Telescopes + Instrumentation.

[6]  Soojong Pak,et al.  Fabrication of electroless nickel plated aluminum freeform mirror for an infrared off-axis telescope. , 2015, Applied optics.

[7]  Giuseppe Valsecchi,et al.  Electroformed off-axis toroidal aspheric three-mirror anastigmat multispectral imaging system , 2014 .

[8]  Zhu Jun,et al.  Design of a low F-number freeform off-axis three-mirror system with rectangular field-of-view , 2015 .

[9]  Amit Gupta,et al.  Optical design of off-axis Cassegrain telescope using freeform surface at the secondary mirror , 2015 .

[10]  Juan C. Miñano,et al.  Optical design through optimization using freeform orthogonal polynomials for rectangular apertures , 2015, SPIE Optical Systems Design.

[11]  Milan Maksimovic.  Optical design and tolerancing of freeform surfaces using anisotropic radial basis functions , 2016 .

[12]  R. Upton,et al.  Gram-Schmidt orthogonalization of the Zernike polynomials on apertures of arbitrary shape. , 2004, Optics letters.

[13]  Emmanuel Hugot,et al.  Active optics: single actuator principle and angular thickness distribution for astigmatism compensation by elasticity. , 2008, Applied optics.

[14]  K. Thompson,et al.  A new family of optical systems employing φ-polynomial surfaces. , 2011, Optics express.

[15]  P. Peumans,et al.  The optical advantages of curved focal plane arrays. , 2008, Optics express.

[16]  Harald Ries,et al.  Double tailoring of freeform surfaces for off-axis aplanatic systems , 2012, Optical Systems Design.

[17]  Michael P. Chrisp,et al.  Imaging freeform optical systems designed with NURBS surfaces , 2016 .

[18]  Gregg E. Davis,et al.  Assembly of a freeform off-axis optical system employing three φ-polynomial Zernike mirrors. , 2014, Optics letters.

[19]  Michael P. Chrisp.  New freeform NURBS imaging design code , 2014, Other Conferences.

[20]  Rong Shu,et al.  A freeform-based, fast, wide-field, and distortion-free camera for ultralow surface brightness surveys , 2014, Astronomical Telescopes and Instrumentation.

[21]  Jingfei Ye,et al.  Comparative assessment of orthogonal polynomials for wavefront reconstruction over the square aperture. , 2014, Journal of the Optical Society of America. A, Optics, image science, and vision.

[22]  S. Pascal,et al.  New modelling of freeform surfaces for optical design of astronomical instruments , 2012, Other Conferences.

[23]  Tong Yang,et al.  Direct design of freeform surfaces and freeform imaging systems with a point-by-point three-dimensional construction-iteration method. , 2015, Optics express.

[24]  Qingyu Meng,et al.  Off-axis three-mirror freeform telescope with a large linear field of view based on an integration mirror. , 2016, Applied optics.

[25]  Pradyumna Kumar Swain,et al.  Curved CCDs and their application with astronomical telescopes and stereo panoramic cameras , 2004, IS&T/SPIE Electronic Imaging.

[26]  Christophe Devilliers,et al.  Mirror actively deformed and regulated for applications in space: design and performance , 2013, 1305.0476.

[27]  Richard N. Youngworth,et al.  Lens design with Forbes aspheres , 2008, Optical Systems Design.

[28]  Bernard Delabre,et al.  First results from a novel curving process for large area scientific imagers , 2012, Other Conferences.

[29]  Ulrike Fuchs,et al.  Discussing design for manufacturability for two freeform imaging systems , 2016, Optical Engineering + Applications.