Diffraction grating

About: Diffraction grating is a research topic. Over the lifetime, 24884 publications have been published within this topic receiving 372437 citations. The topic is also known as: grating.

Submicrometer gratings for solar energy applications.

Abstract: Diffractive optical structures for increasing the efficiency of crystalline silicon solar cells are discussed. As a consequence of the indirect band gap, light absorption becomes very ineffective near the band edge. This can be remedied by use of optimized diffraction gratings that lead to light trapping. We present blazed gratings that increase the optically effective cell thickness by approximately a factor of 5. In addition we present a wideband antireflection structure for glass that consists of a diffraction grating with a dielectric overcoat, which leads to an average reflection of less than 0.6% in the wavelength range between 300 and 2100 nm.

Compact and Highly Efficient Grating Couplers Between Optical Fiber and Nanophotonic Waveguides

Abstract: We present high-efficiency grating couplers for coupling between a single-mode fiber and nanophotonic waveguides, fabricated both in silicon-on-insulator (SOI) and InP membranes using BenzoCycloButene wafer bonding. The coupling efficiency is substantially increased by adding a gold bottom mirror to the structures. The measured coupling efficiency to fiber is 69% for SOI grating couplers and 56% for bonded InP membrane grating couplers

Polarization dependent focusing lens by use of quantized Pancharatnam–Berry phase diffractive optics

Abstract: Quantized Pancharatnam–Berry phase diffractive optics using computer-generated space-variant subwavelength dielectric grating is presented. The formation of the geometrical phase is done by discrete orientation of the local subwavelength grating. We discuss a theoretical analysis and experimentally demonstrate a quantized geometrical blazed phase of polarization diffraction grating, as well as polarization dependent focusing lens for infrared radiation at wavelength 10.6 μm.

Pancharatnam Berry phase in space-variant polarization-state manipulations with subwavelength gratings

Abstract: We report the appearance of a geometrical phase in space-variant polarization-state manipulations. This phase is related to the classic Pancharatnam–Berry phase. We show a method with which to calculate it and experimentally demonstrate its effect, using subwavelength metal stripe space-variant gratings. The experiment is based on a unique grating for converting circularly polarized light at a wavelength of 10.6 μm into an azimuthally polarized beam. Our experimental evidence relies on analysis of far-field images of the resultant polarization.