Dwi Astuti Wijayanti, Matsukuma Hiraku, Nakao Masaru, Li Kuangyi, Shimizu Yuki, Gao Wei
Precision Nanometrology Laboratory, Department of Finemechanics, Tohoku University, Sendai 980-8579, Japan.
Department of Electrical Engineering and Informatics, Vocational School, Universitas Gadjah Mada, Yogyakarta 55281, Indonesia.
Sensors (Basel). 2021 Jan 19;21(2):670. doi: 10.3390/s21020670.
This paper proposes a new optical angle measurement method in the optical frequency domain based on second harmonic generation with a mode-locked femtosecond laser source by making use of the unique characteristic of the high peak power and wide spectral range of the femtosecond laser pulses. To get a wide measurable range of angle measurement, a theoretical calculation for several nonlinear optical crystals is performed. As a result, LiNbO crystal is employed in the proposed method. In the experiment, the validity of the use of a parabolic mirror is also demonstrated, where the chromatic aberration of the focusing beam caused the localization of second harmonic generation in our previous research. Moreover, an experimental demonstration is also carried out for the proposed angle measurement method. The measurable range of 10,000 arc-seconds is achieved.
本文提出了一种基于锁模飞秒激光源二次谐波产生的光学频域新型光学角度测量方法，该方法利用了飞秒激光脉冲的高峰值功率和宽光谱范围这一独特特性。为了获得较宽的角度测量范围，对几种非线性光学晶体进行了理论计算。结果表明，所提出的方法采用了铌酸锂晶体。在实验中，还证明了使用抛物面镜的有效性，在我们之前的研究中，聚焦光束的色差导致了二次谐波产生的定位。此外，还对所提出的角度测量方法进行了实验验证。实现了10000角秒的测量范围。
