论文标题
超薄宽带反射性光学限制器
Ultrathin broadband reflective optical limiter
论文作者
论文摘要
光学限制器是非线性设备，具有随着入射力强度的增加而具有降低的透射率，因此可以保护敏感组件免受高强度照明。理想的光学限制器反射而不是在其主动（“限制”）状态下吸收光，从而最大程度地减少了对限制器本身损坏的风险。以前的实现反射限制器的努力是基于将非线性层嵌入到相对较厚的多层光子结构中，从而导致了实质性的制造复杂性，速度降低，并且在某些情况下，工作带宽有限。我们通过在二氧化钒（VO2）中使用绝缘体到金属过渡来克服这些权衡，以实现通过孔径天线的谐振传播的强度依赖性调节。由于跨绝缘子到金属过渡的光学特性发生了巨大变化，因此低质量的谐振器足以实现设备传输的高启用比率。结果，就操作波长（> 2 um> 2 um）和入射角（距正常值左右〜50 $°$远），我们的超薄反射限量（自由空间波长的厚度〜1/100）是宽带。
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 optical limiter reflects rather than absorbs light in its active ("limiting") state, minimizing risk of damage to the limiter itself. Previous efforts to realize reflective limiters were based on embedding nonlinear layers into relatively thick multilayer photonic structures, resulting in substantial fabrication complexity, reduced speed and, in some instances, limited working bandwidth. We overcome these tradeoffs by using the insulator-to-metal transition in vanadium dioxide (VO2) to achieve intensity-dependent modulation of resonant transmission through aperture antennas. Due to the dramatic change of optical properties across the insulator-to-metal transition, low-quality-factor resonators were sufficient to achieve high on-off ratios in device transmittance. As a result, our ultra-thin reflective limiter (thickness ~1/100 of the free-space wavelength) is broadband in terms of operating wavelength (> 2 um at 10 um) and angle of incidence (up to ~50$°$ away from the normal).
