摘要
红外热像仪可在全天候条件下实现目标识别,在安防、夜视辅助及红外测温系统等领域应用广泛,但红外热像仪成像质量和效果受制于ZnS红外光学镜头的品质和性能。文中采用自主研制的三温区梯度化学气相沉积(TTG-CVD)及退火热处理制备ZnS块体。采用X射线衍射表征出ZnS块体是立方闪锌矿结构,具有光学各向同性,可以满足后续在红外光学镜头中的设计需求。结合红外透过光谱获得ZnS块体在8~12μm长波红外波段的平均透过率达71.6%。ZnS块体在1.06μm处的折射率均匀性为1.94×10^(-5)。进一步采用光学冷加工和单点金刚石车削等工艺,制作出ZnS红外光学透镜和红外镜头。红外光学镜头在空间频率为20 lp/mm时,在半视场(0.5视场)和0.707视场的调制传递函数(MTF)接近衍射极限。红外成像系统在中心视场、0.707视场由像差引起的弥散斑均方根值(RMS)均小于像元尺寸20μm,系统畸变小于1%,各项指标均达到实际使用要求。
Infrared thermal imagers are widely used in security,night vision and infrared temperature measurement with the advantages of target recognition under all-weather conditions.However,the imaging quality is restricted by the quality of ZnS infrared optical lens.The annealed ZnS bulk was fabricated through Three-Temperature zone Gradient Chemical Vapor Deposition(TTG-CVD)furnace.The ZnS bulk with cubic sphalerite structure was characterized by X-ray diffraction.No hexagonal wurtzite structure was detected.It indicates that ZnS bulk possessing optically isotropic property,which can meet the design requirements in lens.The average transmittance of ZnS bulk was measured as 71.6%in the long-wavelength infrared band of 8-12μm.The refractive index uniformity of ZnS bulk was measured as 1.94×10^(-5)at 1.06μm.As encouraged by the above optical parameters,ZnS infrared optical lens was further produced by adopting optically cold-mechanical process and single-point diamond turning techniques.When the spatial frequency of ZnS infrared optical lens was 20 lp/mm,the modulation transfer function(MTF)of the half or 0.707 field of view was close to the diffraction limit.The root mean square value(RMS)of the diffuse speckle caused by aberration in the central field and 0.707 field of view was less than 20μm in the pixel size.Meanwhile,the system distortion was less than 1%in the infrared imaging system.It shows TTG-CVD based ZnS crystal is promising for infrared applications.
作者
吴绍华
黄攀
赵劲松
赵跃进
郑丽和
董汝昆
Wu Shaohua;Huang Pan;Zhao Jingsong;Zhao Yuejin;Zheng Lihe;Dong Rukun(School of Physics,Beijing Institute of Technology,Beijing 100081,China;Kunming Institute of Physics,Kunming 650217,China;Yunnan KIRO Photonics Co.,Ltd.,Kunming 650217,China;School of Optics and Photonics,Beijing Institute of Technology,Beijing 100081,China;School of Physics and Astronomy,Yunnan University,Kunming 650500,China)
出处
《红外与激光工程》
EI
CSCD
北大核心
2021年第10期172-177,共6页
Infrared and Laser Engineering
基金
云南省科技创新强省计划专项(2014AA023)
国家自然科学基金联合基金(U1830104)。
关键词
ZnS块体
折射率均匀性
红外光学镜头
调制传递函数
红外成像
ZnS bulk
refractive index uniformity
infrared optical lens
modulation transfer function
infrared imaging
作者简介
吴绍华,男,高级工程师,博士,主要从事红外光学材料的制备和应用等方面的研究;通讯作者:赵劲松,男,教授级高级工程师,博士,主要从事红外热像仪的总体技术、装配与测试技术、偏振成像技术以及多光谱成像技术等方面的研究;通讯作者:赵跃进,男,教授,博士,主要从事光电仪器设计、红外成像技术、太赫兹技术、图像处理技术等方面的研究。
