Mono-Order High-Efficiency Dielectric Concave Diffraction Grating

A planar concave diffraction grating for integrated optics is created by using a grating-distributed Bragg reflector based on dielectric materials. By combining the Bragg condition which leads to very high reflection with the grating diffraction condition which provides wavelength spreading, a mono-order diffraction grating was built with the use of elliptical facets. A computed grating efficiency of 99% was achieved by this new proposed configuration of mono-order grating by suppressing unwanted diffraction orders, while keeping aberration-free focusing.