Acoustic-Magnetic Tunable Liquid Crystal Microlens Arrays for Polarization-Selective Imaging

Abstract

Microlens arrays (MLAs) are pivotal in numerous applications, yet solid microlenses encounter significant challenges in achieving tunable optical properties, thereby limiting their applications. In this study, reconfigurable and polarization-dependent tunable MLAs are reported by multifield-based assembly and modulation of the optical anisotropy lens units. Nematic liquid crystal (NLC) droplets are assembled into uniform and large-area MLAs within designed periodic acoustic potentials, obtaining reconfigurable structures and tunable array periods. In addition, droplets containing dispersed ferroferric oxide (Fe₃O₄) nanoparticles (NPs) are produced, endowing the magnetic control of the LC’s spatial alignment and thus achieving polarization selectivity. The combination of acoustic and magnetic modulation allows high flexibility in converting polarization-selective imaging capability and breaks the coupling between translation and rotation, enabling individual rotation by the magnetic field and translation by the acoustic field, respectively. Further modulation in acoustic signal amplitude can also switch the ability to polarization-selective imaging on and off. With such features, these MLAs are proven to be capable of selectively obtaining images of objects with different polarization states. This strategy offers a new route in optical tunable microlens and MLA fabrication and modulation, with the advantages of being robust, flexible, and low cost, exhibiting potential in miniaturized optical systems, integral imaging, and three-dimensional displays.