Micro-optical lenslets by photo-expansion in chalcogenide glasses
Micro-optical lenslets by photo-expansion in chalcogenide glasses
复制标题
硫属化物玻璃中的光膨胀微光学透镜
DOI：
10.1109/50.618346
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发表时间：
1997
影响因子：
4.7
通讯作者：
S. G. Bishop
中科院分区：
文献类型：
--
作者：
S. Ramachandran;J. Pepper;D. Brady;S. G. Bishop
报道了硫系玻璃中光膨胀形成小透镜的波长依赖性的详细研究。硫族化物玻璃中的光膨胀提供了一种一步制造工艺来记录光栅和微透镜等表面结构。该过程是纯光学的，无需固定和蚀刻即可获得所需的表面结构。两种相互竞争的效应，即低能光子获得的大体积和高能光子导致的大幅光结构变化，提供了使用不同制造技术通过光膨胀过程获得小透镜的可能性。使用强烈吸收的 514.5 nm 光来记录 As/sub 2/S/sub 3/ 玻璃中的微光学小透镜，并观察到高达 10% 的相对体积变化。该波长下的低功率密度要求用于演示用于记录小透镜的并行光刻制造技术，该技术具有高重复性和吞吐量，并且对曲率和尺寸具有出色的控制。表面膨胀的幅度在光子能量下最大化，该光子能量结合了短波长曝光在产生大百分比体积变化方面的优点和低能量光子在照射大体积玻璃基质方面的优点。采用光学吸收边乌尔巴赫尾部范围内的各种波长来寻找 As/sub 2/S/sub 3/玻璃中大绝对体积变化的最佳波长。高达 8 /spl mu/m 的小透镜是使用 584.5 nm 染料激光器的聚焦光曝光制造的。小透镜在结构上通过 alpha 步扫描仪和原子力显微镜 (AFM) 进行表征，并通过使用这些小透镜测试从单模光纤发出的 1550 nm 光的准直来进行光学表征。
A detailed study of the wavelength dependence of the formation of lenslets by photo-expansion in chalcogenide glasses is reported. Photo-expansion in chalcogenide glasses offers a one-step fabrication process to record surface structures such as gratings and microlenses. The process is purely optical and requires no fixing and etching to get the desired surface structure. Two competing effects, namely large volumes accessed by low energy photons and large magnitudes of photostructural changes due to high energy photons, provide the possibility of using different fabrication techniques to obtain lenslets by the photo-expansion process. Strongly absorbed 514.5 nm light is used to record micro-optical lenslets in As/sub 2/S/sub 3/ glass and up to 10% relative volume changes are observed. The low power density requirements at this wavelength are used to demonstrate a parallel lithographic fabrication technique for recording lenslets with high repeatability and throughput, and with excellent control over curvature and dimensions. The magnitude of surface dilation is maximized at the photon energy that combines the advantage of short wavelength exposures in producing large percentage volume changes, with the advantage of low energy photons in irradiating large volumes of the glass matrix. A variety of wavelengths within the Urbach tail range of the optical absorption edge are employed to find the optimal wavelength for large absolute volume changes in As/sub 2/S/sub 3/ glass. Lenslets as high as 8 /spl mu/m are fabricated with focused light exposures from a dye laser operating at 584.5 nm. Lenslets are structurally characterized with alpha-step scanners and an atomic force microscope (AFM) and are optically characterized by testing the collimation of 1550-nm light emerging from a single-mode fiber with these lenslets.