Study of influence of the removal depth of the silicon modification layer on grating structures in reaction-sintered silicon carbide substrate and improvement method.

The influence of the removal depth of a silicon modification layer on grating structures and mirrors is studied. The removal depth 6-14 μm is the optimization result for Si-modified reaction-sintered silicon carbide (RS-SiC) used as mirror substrates, but the removal depth 9-12 μm is the optimization result for Si-modified RS-SiC used as grating substrates. The diffraction efficiency and stray light of the gratings fabricated in the Si-modified RS-SiC substrates with removal depth 9-12 μm is 90.5%-94% and 5.30×10-5.45×10, respectively. Additionally, the number and scale of high-reflection points can be used as the basis for judging the removal depth of the Si-modified RS-SiC used as grating substrates. These results and the regularity have guiding significance for the application of Si-modified RS-SiC as a microstructural substrate.