Micro-patterned photo-aligned ferroelectric liquid crystal Fresnel zone lens

Abstract

In this Letter, we disclose a fast switchable Fresnel zone lens (FZL) by confining the ferroelectric liquid crystals (FLCs) in multiple microscopically defined photo-aligned alignment domains. The photo-alignment (PA) offers good control on the anchoring energy (W) by mean of irradiation doses (ID) and thus excellent alignment for FLCs. Two operational modes of the FLCFZL, i.e., FOCUS/OFF and FOCUS/DEFOCUS, were demonstrated. The proposed diffracting element provides fast response time, high diffraction efficiency (η), with saturated electro-optical (EO) operations up to high frequency (≈2 kHz). Thus, the proposed FLCFZLs with simple fabrication open several opportunities to improve the quality of existing devices and to find new applications.