Designing high efficiency uniform-intensity splitter with binary-phase subwavelength structure

Abstract

Dammann grating designed by using the scalar diffractive theory is a conventional uniform-intensity splitter with binaryphase, whose diffraction efficiency is no more than 87% generally and representative value is about percent 80. This will limit its further progress. Based on the rigorous couple-wave analysis theory and the genetic algorithm, a method has been proposed to design a new uniform-intensity splitter with binary-phase subwavelength structure, which has higher diffraction efficiency. Then five new-type beam splitters with binary-phase, whose splitting ratios are 3, 4, 5, 6 and 7, are obtained by the emulating package. Their diffraction efficiency is more than 92%, and it is very bigger than the conventional Dammann grating. Owing to its subwavelength structure, the size of this kind of splitter is smaller. It will be widely applied in some domains, such as ultra-precision manufacturing, micro-opto-electro-mechanical system, information processing, optical fiber communication, biomedicine, national defense, military affairs and entertainment, etc.