Ultrathin Broadband Reflective Optical Limiter

Optical limiters are nonlinear devices that feature decreasing transmittance with increasing incident optical intensity, and thus can protect sensitive components from high-intensity illumination. The ideal limiter reflects rather than absorbs light in its active (“limiting”) state, minimizing risk of damage to the itself. Previous efforts realize reflective (rather absorbing) were based on embedding layers into relatively thick multilayer photonic structures, resulting substantial fabrication complexity, reduced speed and, some instances, limited working bandwidth. In this paper, these tradeoffs overcome by using insulator-to-metal transition (IMT) vanadium dioxide (VO2) achieve intensity-dependent modulation resonant transmission through aperture antennas. Due large change properties across IMT, low-quality-factor resonators sufficient high on–off ratios limiter. As a result, our ultrathin (thickness ?1/100 free-space wavelength) is broadband terms operating wavelength (>2 µm at 10 µm) angle incidence (up ?50° away normal). Our analysis experimental results via opto-thermal simulations provides insight performance useful guidance for further engineering efforts.