Multilevel phase-type diffractive lens embedded in sapphire
Multilevel phase-type diffractive lens embedded in sapphire
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嵌入蓝宝石的多级相位型衍射透镜
DOI：
10.1364/ol.42.003832
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发表时间：
2017-10-01
期刊：
影响因子：
3.6
通讯作者：
Sun, Hong-Bo
中科院分区：
文献类型：
--
作者：
Li, Qian-Kun;Lu, Yi-Ming;Sun, Hong-Bo
本文报道了一种利用飞秒激光在蓝宝石晶体内部诱导折射率变化的相息图相位型透镜（KPL）。通过在蓝宝石中制作体相位光栅，测量光栅一、二级衍射能量比，得到飞秒激光对蓝宝石折射率的影响。根据实验建立的折射率变化与飞秒激光功率的关系，设计并制作了一个四能级KPL。重要的是，KPL具有独特的紫外聚焦和成像能力，以及在不同折射率环境中稳定的光学性能。嵌入蓝宝石中的KPL在高温（1050摄氏度）退火30分钟后具有相同的光学性能。蓝宝石中的KPL在提高GaN蓝紫外发光二极管的光提取效率方面具有巨大的潜力，可用于化学恶劣和高温环境中的微光学传感器应用。(C)2017美国光学学会
Herein, we report a kinoform phase-type lens (KPL), which is fabricated by femtosecond (fs)-laser-induced refractive index change inside sapphire crystal. By fabricating volume phase gratings in sapphire and measuring the energy ratio of the grating's first and second diffraction orders, the refractive index change in sapphire induced by fs-laser modification was obtained. Then a four-level KPL was designed and fabricated inside sapphire following the experimentally established scaling of the refractive index change and fs-laser power. Importantly, the KPL has unique UV focusing and imaging capability as well as a stable optical performance in different refractive index environments. The KPL embedded in sapphire has the same optical performance after a high-temperature (1050 degrees C) annealing for 30 min. The KPLs in sapphire have great potential to increase light extraction efficiency in GaN blue-UV lightemitting diodes and can be used in micro-optical sensor applications in chemically harsh and high-temperature environments. (C) 2017 Optical Society of America