Opt Lett. 2018 Dec 15;43(24):6069-6072. doi: 10.1364/OL.43.006069.
Diffraction gratings are transversally inscribed in the bulk of monolithic crystalline silicon with infrared nanosecond laser pulses. Nanoscale material analyses of the modifications composing the gratings show that they rely on laser-induced stress associated with a positive refractive index change as confirmed with phase-shift interferometry. Characterizations of the optical properties of the gratings, including the diffraction angles and the efficiency of the different orders, are carried out. The refractive index change obtained from these measurements is in good agreement with the phase-shift measurements. Finally, we show that the grating diffraction efficiency depends strongly on the laser writing speed.
衍射光栅是利用红外纳秒激光脉冲在块状单晶硅中横向刻写而成的。对构成光栅的修改材料的纳米级分析表明，它们依赖于激光诱导的应力，该应力与正折射率变化相关，这一点通过相移干涉测量得到了证实。对光栅的光学特性进行了表征，包括衍射角和不同阶的效率。这些测量得到的折射率变化与相移测量结果吻合较好。最后，我们表明光栅的衍射效率强烈依赖于激光写入速度。
