15倍双组联动红外连续变焦系统的初始结构计算

 双组联动型变焦结构是由2个固连在一起的变倍组做线性运动,补偿组做非线性运动的变焦系统,兼有光学补偿和机械补偿两种特点,较易实现大的变倍比,系统长度较短且凸轮曲线较为平缓。求解变焦各组份高斯参数的出发点是保证变焦核能够实现所需变倍比的情况下,各个运动组份的位移之和为零且像面稳定。利用P∞W∞法与光学结构参数之间的关系确定各组份的半径和材料,最后利用CODEV软件设计出满足设计要求的初始结构。     

非制冷长波红外热像仪折衍混合双视场光学系统设计

根据衍射光学元件具有大的负向色散特性,将衍射光学元件应用于红外双视场光学系统中,根据傅里叶光学分析衍射光学元件(DOE)的消色差,列表对比折射透镜与衍射光学透镜的特性,并给出变倍比为4∶1可用作非制冷红外热像仪的光学系统的具体设计实例.系统采用切入式变焦方式,在短焦时切入2片透镜实现宽视场,通过引入二元面和非球面提高了成像质量.设计结果表明:在空间频率11 lp/mm处,短焦距40 mm时,各个视场的MTF值均大于0.6;长焦距160 mm时,各个视场的MTF值均大于0.7,宽视场和窄视场都具有较好的成像质量.     

Automatic measurement device of laser-induced damage threshold and its experiment北大核心

A set of 1 064 nm and 532 nm automatic measurement device of laser-induced damage threshold (LIDT) of dual-wavelength optical elements was designed and constructed for automatic detection of LIDT of optical elements film. The device was mainly composed of pulsed laser light source, beam parameter diagnosis component, damage online diagnosis component, scanning motion platform for parts to be tested and control system. The whole measuring device and measurement process were automatically controlled by the computer integrated measuring software based on Labview, which could realize the automatic measurement of damage threshold in the range of energy density from 0.1 J/cm2～100 J/cm2, and the device was also used to measure the 1 064 nm antireflection film and aluminum reflection film samples. The results show that the damage thresholds are 27.09 J/cm2 and 3.21 J/cm2, with a relative uncertainty of 3.91% and 5.61%, respectively. © 2023 Editorial office of Journal of Applied Optics. All rights reserved.