Self‐Excited Free‐Standing VO2 Film for Infrared Optical Limiter

Abstract Effective optical limiters (OLs) are necessary devices for the protection of various sensitive photo‐detectors, cameras, infrared sensors, or even the human eyes once encountering unexpected high‐intensity illumination or laser blinding attacks. Vanadium dioxide (VO 2 ) shows pronounced infrared switching behavior across the phase transition, which is considered as an idea optical limiter for broad‐band infrared laser protection. However, the self‐adapting optical limiter function based on VO 2 is quite difficult to realize since the open‐state absorptance of the VO 2 layer is always very low, which makes the laser irradiation cannot trigger the phase transition quickly. In the current study, a self‐excited VO 2 infrared optical limiter is proposed, which is integrated by a transferred VO 2 layer, InGaAs micro/nano wires, and a local heater. Based on the“optical response–electric heating” strategy, the phase transition of VO 2 layer can be quickly triggered once the incident laser beam intensity exceeds the pre‐set threshold value. In addition, this integrated device has an excellent switching ratio, flexible controllability, and stability. This work achieves a practical VO 2 optical limiter device and provides a promising strategy for developing VO 2 ‐based integrated multifunctional devices in the future.