Tunable all-optical liquid crystal lens based on the thermo-plasmonic effect

Abstract

Surface plasmon resonance (SPR) thermal effects have been the focus of researchers lately and are commonly used in sensors, micro heaters in integrated circuits, and other applications. In this study, a new type of tunable all-optical liquid crystal (LC) lens is fabricated by employing the SPR thermal effects. Due to the absorption of pump light by gold nanoparticles, the generated heat is transferred to the surrounding LC layer, leading a radial gradient distribution of LC molecules. Passing a probe light through the center of the fabricated cell, a lens shaped optical phase retardation observed. The temperature increase with intensification of the pump light power has been numerically calculated. In addition, the focal length of the lens reduces from 157.8 to 13.1 cm during this process. The tunable all-optical LC lens is a fascinating new concept that could open up new horizons and has numerous applications. It has a simpler and cheaper structure compared to electronic lenses, provides greater stability than other all-optical counterparts, and allows for optical control of the focal length.