Modeling of a multilayer dielectric stack Notch filter for visible spectrum

Abstract

In this work, a multilayer dielectric optical notch filters design for visible spectrum 450-700 nm is proposed based on TiO2 and SiO2 alternating layers. Titanium dioxide (TiO2) is selected for its high refractive index value (2.5) and Silicon dioxide (SiO2) as a low refractive index layer (1.45). These filters are conventionally anticipated for overpowering of powerful laser beams in research experiments, to obtain good signal-to-noise ratios in Raman laser spectroscopy. The designed filter shows a high quality with average transmission of more than 90% in 450-535 and 587-700 nm wavelength ranges. And a stop band region between 536-586 nm with a FWHM of 50 nm shows a transmission of 3% with an optical density of greater than 3, which makes it a promising element to be used as notch filter.