Phase-conjugated directional diffraction from a retroreflector array hologram

Abstract

A corner cube retroreflector (CCR) consists of three perpendicular flat surfaces and reflects the incident light back to its source. Optical properties of CCR arrays have applications in free space optical communication, low power wireless networks and sensing applications. Conventional top-down CCR array fabrication is complex and requires expensive equipment and limited to broadband reflection only. Here, we utilize laser assisted copying of a CCR array to a light sensitive holography polymer film (∼10 μm) which was placed parallel to the object plane (CCR array) during the recording. Optical characterization of the recorded CCR array hologram was carried out using reflection and color-selective diffraction measurements. Angle dependent optical properties were also simulated computationally followed by their experimental realization, which confirm our experimental findings. In a broadband illumination setting, a broadband white light reflection and a narrowband color diffraction were observed. A linear relationship between the incidence angle of the broadband light and the diffraction angle of the diffracted color light was observed. Bright and well-defined 2^nd order far-field diffraction patterns were observed using an image-screen experiment. Maximum diffraction efficiency (DE) of ∼50% was observed for the monochromatic green light at normal illumination setting. The far-field diffraction interspacing/intensity exhibits increasing/decreasing trend with illumination tilt angles, measured between 10 to 50 degrees. The recorded CCR array holograms offer potential applications in color selective diffraction optics and customized optical devices.