Transmittance Properties of 18-Layered Interference Filters

Abstract

In this study, the design and transmittance properties of lowpass (having low transmittance region) and highpass (having high transmittance region) interference filters, formed by using SiO2 and TiO2 were investigated. The absorption edge of light filtered through a single layered filter is not very sharp. In this regard, single layered system can not yield the desired result. However, multilayered interference filters sharpen the absorption edge of the filtered light and absorb the region completely where transmittance is not desired. In this study, transmittance properties of the interference filters formed with vacuum evaporation technique were investigated with UV spectroscopy and the main absorption edge and peak transmittance of the light passing through lowpass and highpass filters were found to be 580 and 500 nm and 91% and 93.5% in visible region, respectively. In addition, EDX spectra were obtained to determine the characteristics of the layers.