Polarization- and wavelength-selective photodetectors

Abstract

A photodetector that is selective to the polarization, the frequency, and the angle of incident light is presented. Surface plasma modes excited at the surface of a semiconductor–metal–insulator structure provide selective coupling of light into the semiconductor with increased quantum efficiency. Two types of surface modes (TM0 and TE0) are realized by special choices of grating periodicity and insulator film thickness. TM0 modes have a resonant sensitivity to p-polarized light, whereas TE0 modes have a resonant sensitivity to s-polarized light. In addition, for both types of mode the resonance frequency is tunable in a wide range. By combining the selective properties of the surface modes with conventional photodetective devices, we can realize frequency, polarization, and angle-dependent detectors.