Parametric optimization of narrow bandstop optical filters using the self-suspended subwavelength grating for TE polarization

Abstract

Instead of a conventional fixed multilayer grating, a self-suspended subwavelength grating (SSG) which consists of a single grating layer and possesses tunable functions, is investigated by the rigorous coupled-wave method in detail. Through optimizing various parameters including the incident wavelength, the grating period, the grating thickness and the grating filling factor, we demonstrate that the silicon dioxide (SiO₂) SSG owns a narrow reflectance linewidth in the case of TE polarization. For the SiO₂ SSG, the reflectance peak splits into two branches when the incident light deviates from normal incidence. In addition, the reflectance property of the SiO₂ SSG with unoptimized parameters is also presented for comparison, which exhibits a much larger reflectance linewidth. It is expected that the SiO₂ SSG should be used as narrow bandstop optical filters for TE polarization in micro optics systems.

Keywords:

• SiO₂ self-suspended subwavelength grating
• TE polarization
• rigorous coupled-wave method
• reflectance linewidth
• narrow bandstop optical filters

Acknowledgements

This work was supported by the Grant-in-Aid for Scientific Research (17068002). This work was also supported by Grant-in-Aid for Publication of Scientific Research Results (18·06375) from the Japan Society for the Promotion of Science (JSPS).