Multiplexed computer-generated waveguide hologram using gratings with different spatial frequencies

We propose and experimentally demonstrate a multiplexed off-plane computer-generated waveguide hologram, using waveguide gratings with different spatial frequencies. Two spot arrays are produced at different deflection angles and simultaneously focused at different focal lengths above the waveguide. Electron-beam lithography and reactive ion beam etching were used in fabricating this device. The uniformity error and the diffraction efficiency were measured to be approximately 10% and 55%, respectively.