Designing and manufacturing of interference notch filter with a single reflection band

Abstract

The main idea of this work is to design a notch filter structure with a narrow notch width and maximum reflection while reducing fabrication challenges. In addition, using anti-reflection layers in the outermost part of the designed structure, the pass-band ripples are reduced. In this study, we considered [(nHnL)s (mHmL)p (nHnL)z] structure with n=5 and m=3. Using this form of design and combining 3 and 5 quarter-wave coefficients instead of 1 and 3, we could reach a narrower NW in fewer periods of HL layers. The stability of the deposition conditions and the density of the layers affect their quality and consequently the result of environmental tests. Hence, to construct the designed structure, we employed the sputtering method with RF and DC sources. In our experiments, we showed that the use of a simple shield prevents the oxidation of targets’ surfaces as well as reduces the deposition rate and increases the stability of deposition processes. Fabricated Samples have been subjected to a variety of environmental tests, including humidity, hard and soft abrasion, temperature, and adhesion tests with satisfactory results.