ITO-activated reconfigurable micro-lens array for dynamic reversible focusing and collimation

Micro-scale optical components with varifocal manipulation, play a crucial role in imaging and display technology, beam shaping, optical switching, and wavefront-analysis. In order to provide dynamic reversible functionality, these lenses require varifocal capability. Herein, we demonstrate droplet-based micro-lens array for continuous shape regulation from focusing to collimation. Based on high transmittance of 80.41% at 808 nm wavelength and photothermal effect of surface plasmon wave, these ITO-activated microlenses can be dynamically reconfigured and thus display reversible focusing state of convex profile and collimation state of plane profile. As a result, the excellent vision of varifocal ability is unprecedentedly tuned from 155 µm to 1300 µm within a short time of 30 s. Meanwhile, these tunable micro-lenses accurately control the focal length by changing the irradiation duty ratio of laser pulse. Therefore, we demonstrate the fundamental characteristics and promising opportunities of ITO-activated microlenses for fluid-based refractive optical system.