Electrowetting retroreflectors: Scalable and wide-spectrum modulation between corner cube and scattering reflection

摘要

Corner cube and spherical retroreflectors are ubiquitous in conspicuity and range-finding applications since they reflect light back to the illumination source with unmatched efficiency. We report here a switchable electrowetting retroreflector platform that provides multiple novel features, including (a) using <0.5 μJ/cm~2 electrical energy to switch from a light scattering state, (b) low loss and wide spectrum as limited only by the absorption spectrum of water, (c) use of ultrasimple self-assembly of 10~3-10~5 liquid lenslets/in. on a polymer/Al corner-cube substrate, and (d) change in retroreflected irradiance of > 10:1 over a ±30° field of view.