Sensitivity-directed refinement for designing broadband blocking filters.

T Amotchkina,M Trubetskov,U Brauneck,A Tikhonravov

doi:10.1364/oe.23.005565

Abstract

We developed a new method aimed at designing short-pass filters, long-pass filters and filters blocking sidebands of Fabry-Perot bandpasses. The method is an automated version of a non-straightforward empirical approach invented as a result of many years' experience in design and production of optical coatings. The method allows obtaining near-quarter-wave solutions in a few seconds. In many cases these solutions are more advantageous for deposition systems.

Highlights

Due to tremendous progress in thin film technology and growing demands on coating performances, the development of new design approaches is still in a focus of optical coating engineers
We developed a new method aimed at designing short-pass filters, long-pass filters and filters blocking sidebands of Fabry-Perot bandpasses
Optical coating engineers in order to avoid complicated design solutions invent and use their own empirical approaches aimed at obtaining designs with some specific structures

Summary

Introduction

Due to tremendous progress in thin film technology and growing demands on coating performances, the development of new design approaches is still in a focus of optical coating engineers. The new Sensitivity-Directed Refinement (SDR) method allows obtaining NQWS with excellent spectral performances. The robust version [14] of the SDR algorithm allows taking into account the requirement on stability of the design solutions to possible variations of the refractive indices as well as to errors in layer thicknesses. 2. Description of the Sensitivity-Directed Refinement method ( ) Denote the number of design layers as m , layer thicknesses as d1,..., dm. For the sake of convenience, only the simplest version of the SDR has been presented above In this version the number of layers activated at each step is p = 1. At each step the method allows activating arbitrary number p ≥ 1 of layers having maximum sensitivity values. The levels of errors δH and δL can be used as parameters of SDR

Example 1: designing a blocking filter

Example 2: designing a short-pass filter

Example 3

Findings

Summary