一种红外双波段衍射望远镜的光学设计

第38卷第1期 2019年2月红外与毫米波学报J. In fra re d M illim. W avesVol. 38! No. 1February ,2019文章编号％1001 -9014(2019)01 -0039 -05D O I：10.11972/j. issn. 1001 -9014.2019.01.007 An optical design for dual-band infrared diffractive telescopeW A N G H a o1’2, K A N G F u-Z e n g1 **, Z H A O W e i1, L I Y i-C hao1’2(1. State Key Laboratory of Transient Optics and Photonics,X l* an Institute of Optics andChinese Academy of Sciences’ X i* an 710119 ’China；2. University of Chinese Academy of Sciences’ Beijing 100049’ China)A b s tra ct：In this paper’ the double-layer harmonic diffractive element (H D E) structure is investigated and theop-timization procedure is based on the equation o f diffraction efficiency o f the double-layer diffracti ment. The diffraction efficiency o f the system in the designed middle and far infrared wavebands is larger than99% ’ which improves the image contrast and the imagequality significantly. Anew dual-band infrared double-layerHDEtelescope is designed’ which can work in the middle and far infrared wavebands. It is shown that tlie systemapproximately attains diffraction lim it and is easy to processed.K e y w o rd s: diffraction efficiency ’ HDE ’ optical designP A C S：42. 15. E q’ 07.57.K p一种红外双波段衍射望远镜的光学设计王昊康福增“’赵卫\李毅超u(1.中国科学院西安光学精密机械研究所瞬态光学与光子技术国家重点实验室，陕西西安710119;2.中国科学院大学，北京100049)摘要：深入研究了双层谐衍射光学元件’基于衍射效率方程对双层衍射元件的衍射效率进行优化.光学系统在中波红外和长波红外波段的衍射效率均超过了 99% ’极大地提高了图像的对比度和像质.设计了一款新型的红外双波段衍射望远镜’取得了接近衍射极限的成像质量’易于加工.关键词:衍射效率；H D E;光学设计中图分类号:〇439 文献标识码:AIntroductionA s ig n ific a n t im provem ent in reconnaissance capa­b ility is the p rim a ry goal o f equipm en t developm ent. I t is one m ethod to im prove the equipm en t reconnaissance a­b i l i t y b y u s i n g various in fra re d spectrum to detect the in- fa r e d ra d ia tio n o f the scene at the same tim e. D ue to the in fu e n c e o f atm ospheric transm ission ’ ra d ia tio n charac­te ris tic s o f d iffe re n t scene in the short-w avelength in fra­red (S W I R)’ m edium-w avelength in fra re d(M W I R)and long-w avelength in fra re d( L W I R) have d iffe re n t p e r­form ance. In t he case o f stray ra d ia tio n o r near the heat source ’ L W IR has a strong reconnaissance c a p a b ility ’ w h ile in hot and h u m id e n v iro n m e n t’ M W IR has great advantage over other. I t is obviously to see the diffe re nce between the im age o f the same scene in M W IR andL W IR[1](F ig. 1).By using the spectrum o f d iffe re n t w avelength rangein in fra re d band ’ the target cam o u fa g e in fo rm a tio n canbe e ffe c tive ly e lim in a te d ’ the detection and reco gn itiona b ility o f the target can be im proved and rate o f the system can be reduced.The re fra ctive in d e x o f m aterials in the two bandsvaries greatly ’ b rin g in g d i i c u l t y in achrom atism in in fra­red d u a l band o p tic a l system. W e often take a re fe c tiv e structure to design d u a l band system to avoid the achro­m atic d iffic u lty. R e fe c tiv e system s t m c tu r is com plexth a t coa xia l system w itli a ce n tra l b lo c k ’ r fe c ts th^ sys­tem m o d ulation transfer fu n c tio n’ w h ile off-axis systemw ith o u t cen ter b lo c k is d iffic u lt to alig n. R e fra ctive stru c­tures w h ic h have no cen ter b lo c k and are easy to a lig nReceived date：2018- 04- 24’ revised date：2018- 10- 20 收稿日期：2018- 04- 24 ’ 修回日期：2018-10-20Foundation items % Supported by Nationa Natural Science Foundation of China (61875227)Biography ：WANG Hao(1992-) ’ male’ N antong’ China’ Ph. D. Research area involves optical design and laser propagation in undewater turbulence. E-mail：wanghao14@* Corresponding author：E-mail：kangfuzeng@opt. ac. cn40红外与毫米波学报3 4 5 6 78 9 10 11 12X /\imFig. 3 Diffraction efficiency curves o f general single-layer D O E , single-layer HDE and double-layer HDE ( Red line and green line are diffraction efficiency curves of single-lay­er D O E o f diffraction order * = 1 and designed wavelength !0 = 4 #m and 10 #m , respectively. Blue line, yellow lin e ! pink line and bright blue line are diffraction efficiency curves of single-layer HDE o f $ =3 and designed wave­length !0 =7 #m , w hich’ s diffraction order m is 2, 3, 4 and 5, respectively. Black line is diffraction efficiency curve of double-layer HDE of diffraction order m = 1 and designed wavelength =4 #m and !2 = 10 #m )图3不同衍射元件的衍射 （红和射级次* = 1, 波长A 。