An electrically tunable focusing and filtering infrared liquid-crystal device for light-field imaging and spectral imaging

摘要

In this paper, we propose a novel dual-function infrared liquid-crystal device (DF-ILCD), which can simultaneouslyperform both tunable focusing and filtering functions through applying alternating current (AC) voltage signals. The keyfunctional micro-structure of the DF-ILCD includes: two paralleled 1-mm-thick ZnSe substrates with 20-nm-thickaluminum (Al) films over their inner surfaces and a periodic repetition microholes over both substrates. The Al films actas both high-reflection films and conductive films. The conventional UV-photolithography and wet-etching process areused to fabricate an arrayed micro-hole with a diameter of 120μm and a period of 336μm over each substrate. Themicro-cavity formed between ZnSe substrates has a typical depth of ~12 μm, which is fully filled by a nematicliquid-crystal (LC) materials. Experiments demonstrate that the proposed device exhibit both filtering function based onFabry–Perot (FP) effect and electrically controlled tunable focusing function generated by the micro-hole electrodes,which is very promising for realizing both the light-field imaging and spectral imaging in the infrared wavelength range.