Highly efficient broadband blazed grating in resonance domain

A resonance domain blazed grating, composed of an effective medium structure and a subsequent mode conversion layer, is designed, fabricated, and characterized. Due to the demanding high aspect ratio geometries, a technological approach for multilevel structures, assisted by atomic layer deposition technology, has been developed. The measured efficiency of about 90% exhibits the largest value yet reported for a multi-level fused silica transmission grating in the resonance domain, operating at non Littrow mounting, close to normal incidence.