PHOTOCHEMICAL FABRICATION OF AMORPHOUS SEMICONDUCTOR BY FEMTOSECOND LASER EXPOSURE

飞秒激光曝光光化学制备非晶半导体

• 批准号: 13650790
• 负责人: SUZUKI Yoshiro
• 金额: $ 2.18万
• 依托单位: MIYAGI NATIONAL COLLEGE OF TECHNOLOGY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13650790/
• 关键词: As_2S_3; femtosecond laser; chalcogenide glasses; photo-expansion; glass fabrication; two-photon absorption; light exposure

The photo-expansion an volume increase by light exposure in chalcogenide glasses has received renewed interests from viewpoints of application to glass fabrication. The photo-expansion occurs through not thermal but photochemical processes, and the expansion is restricted to illuminated fractions of glasses. Utilizing these characteristics, formation of micro-optical devices was successfully demonstrated. However, since one-photon processes with cw-light were used for the electronic excitation in most previous studies, the wavelength matching of exposing light to the absorption coefficient of glasses restricts their performance applicable glass species, sizes, and fabrication times. To extend the applicability of photoexpension to glass fabrication, we have proposed in this study to use pulsed laser light with transparent wavelengths for exposure. The band to band excitation is expected through multi-photon processes with the pulsed laser light. Since the absorption coefficient for the multi-photon process depends on the photon density, the exposure time and the penetration depth can be controlled by the laser flux. Since the multiphoton processes enable band to band excitation only if their sum photon energy exceeds the optical gap of the glass, various species of glasses can be fabricated with an identical laser. We exposed As_2S_3 glasses with femtosecond Ti-sapphire laser light and observed the transformation of the glass surface with a laser microscope. Expansion as high as 0.9μm was detected after exposure with 0.41mW laser light for 128s. Laser power dependence of the growth rate of the expansion and the laser transmittance showed that the photo-expansion is induced mainly by a two-photon absorption process of the laser light.

张贴葡萄糖剂玻璃中光暴露的体积增加，从应用到玻璃制造的视点获得了新的兴趣。光扩散不是通过热化学过程而不是光化学过程发生的，并且膨胀仅限于玻璃的照明部分。利用这些特征，成功证明了微光学设备的形成。但是，由于在大多数先前的研究中都使用了带有CW-Light的一个光子过程进行电子兴奋，因此暴露光与玻璃的抽象系数的波长匹配限制了其性能适用的玻璃物种，尺寸和制造时间。为了扩展照相的适用性对玻璃制造的适用性，我们在这项研究中提出，使用具有透明波长的脉冲激光进行暴露。通过脉冲激光的多光子过程，预计频带到频带兴奋。由于多光子过程的抽象系数取决于光子密度，因此暴露时间和穿透深度可以通过激光通量控制。由于多光子过程只有在频带的总和超过玻璃的光学间隙时才能使频带兴奋，因此可以用相同的激光制成各种玻璃。我们用飞秒ti-sapphire激光暴露了AS_2S_3玻璃，并观察到用激光显微镜转化玻璃表面。用0.41MW激光光线暴露于128s后，检测到高达0.9μm的膨胀。激光功率依赖性的膨胀生长速率和激光传输表明，光扩展主要是由激光的两光滥用过程引起的。