A high-resolution optically addressed spatial light modulator based on ZnO nanoparticles

Abstract

An optically addressed spatial light modulator (OASLM) can modulate the wavefront of a read light by displaying a phase pattern or a hologram configured by the intensity distribution of a write light. Using ZnO nanoparticles (NPs) as a novel photoconductor, a high-resolution OASLM was fabricated. A ZnO NP suspension was spin-coated on an indium tin oxide (ITO)-coated glass substrate and annealed to form a photosensitive layer. The device was characterized electrically and optically. The device was operated at low driving voltages in the transmission mode. Updatable recording of a diffraction grating up to 825 lp mm −1 with a diffraction efficiency (DE) of 0.05% and binary holograms with pixel sizes from 2 µm down to 0.72 µm were demonstrated using a 405 nm wavelength write laser and a 635 nm wavelength read laser.