Michihata Masaki, Goda Shuhei, Masui Shuzo, Takahashi Satoru
Department of Precision Engineering, the University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656, Japan.
Sensors (Basel). 2024 Jun 13;24(12):3821. doi: 10.3390/s24123821.
The concept of an optical profiler based on optical resonance was proposed, highlighting the initial requirements for mode number estimation. We proposed a method for estimating the longitudinal mode number of a laser propagating in an external cavity diode laser with high accuracy, utilizing dual-periodic diffraction gratings. These gratings were fabricated using interference lithography. To estimate the mode number, the wavelengths of two different modes are compared. Therefore, the greater the difference between the wavelengths, the higher the accuracy of the mode number determination. While the mode number difference was approximately 35 when using a conventional diffraction grating, this could be increased by a factor of 20 to around 700 using the dual-periodic grating. The relative accuracy achieved was 1.4 × 10.
提出了基于光学共振的光学轮廓仪概念，强调了模式数量估计的初始要求。我们提出了一种利用双周期衍射光栅高精度估计在外腔二极管激光器中传播的激光纵向模式数量的方法。这些光栅是使用干涉光刻制造的。为了估计模式数量，比较了两种不同模式的波长。因此，波长之间的差异越大，模式数量确定的精度越高。使用传统衍射光栅时模式数量差异约为35，而使用双周期光栅时，这一差异可增加20倍，达到约700。实现的相对精度为1.4×10。
