Compact Off-axis Two-mirror Freeform Telescopic Optical System Design with Large Relative Aperture

Xin-ru ZHOU; Hua-tang SONG; Run-hui ZHU; Zhen-zhen SONG; Zhao-lou CAO; Gai-ge ZHENG; Jing-fei YE

doi:10.3788/gzxb20204910.1022002

Journals >Acta Photonica Sinica >Volume 49 >Issue 10 >Page 1002002 > Article

Acta Photonica Sinica
Vol. 49, Issue 10, 1002002 (2020)

Compact Off-axis Two-mirror Freeform Telescopic Optical System Design with Large Relative Aperture

Xin-ru ZHOU, Hua-tang SONG, Run-hui ZHU, Zhen-zhen SONG..., Zhao-lou CAO, Gai-ge ZHENG and Jing-fei YE^*|Show fewer author(s)

Author Affiliations

Department of Optoelectronic Engineering，School of Physics and Optoelectronic Engineering，Nanjing University of Information Science and Technology，Nanjing 210044，China

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DOI: 10.3788/gzxb20204910.1022002 Cite this Article

Xin-ru ZHOU, Hua-tang SONG, Run-hui ZHU, Zhen-zhen SONG, Zhao-lou CAO, Gai-ge ZHENG, Jing-fei YE. Compact Off-axis Two-mirror Freeform Telescopic Optical System Design with Large Relative Aperture[J]. Acta Photonica Sinica, 2020, 49(10): 1002002 Copy Citation Text

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Fig. 1. Optical configuration of off-axis two-mirror telescopic optical system

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Fig. 2. Diagram of a split field with expansion optimization strategy

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Fig. 3. Design result of off-axis two-mirror freeform telescopic optical system with large relative aperture

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Fig. 4. MTF curves of off-axis two-mirror freeform telescopic optical system with large relative aperture

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Fig. 5. Spot diagrams of off-axis two-mirror freeform telescopic optical system with large relative aperture

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Fig. 6. Freeform wavefronts of viewing mirror and focusing mirror in three different fields

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Parameters	Value
Working wavelength/nm	486~656
Relative aperture	1/3.75
Entrance pupil diameter/mm	80
Effective focal length/mm	300
Field of view/(°)	2°(H)×2°(V)
Root Mean Square (RMS) radius of spot diagram/μm	< 10
MTF at 50 lp/mm	> 0.4
Pixel size of detector/μm	10
Physical size of system(X-Y-Z)/mm³	< 100×200×300
Optical configuration	Off⁃axis two⁃mirror without obstruction

Table 1. Design parameters of off-axis two-mirror freeform telescopic optical system

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$x^{m} y^{n}$ terms	Viewing mirror	Focusing mirror
$x$	0	0
$y$	-0.190	-0.159
$x^{2}$	-4.718×10^-4	-3.058×10^-8
$x y$	0	0
$y^{2}$	-3.554×10^-4	1.294×10^-4
$x^{3}$	0	0
$x^{2} y$	-6.939×10^-7	-6.577×10^-7
$x y^{2}$	0	0
$y^{3}$	-8.206×10^-7	-2.772×10^-7
$x^{4}$	1.257×10^-9	7.395×10^-10
$x^{3} y$	0	0
$x^{2} y^{2}$	2.478×10^-9	-1.562×10^-10
$x y^{3}$	0	0
$y^{4}$	1.556×10^-9	-7.114×10^-10