Erçaglar Veysel, Erturk Volkan, Ghobadi Amir, Yildirim Deniz Umut, Ozbay Ekmel
Opt Lett. 2020 Nov 15;45(22):6174-6177. doi: 10.1364/OL.409586.
In this Letter, we numerically propose a temperature-tunable, ultra-narrowband one-way perfect near-infrared radiation absorber with high transmission in the longer wavelength neighboring spectral range. We obtained this functionality by using a guided-mode resonance-based grating-waveguide metamirror that is comprised of silicon, a spacer dielectric, an absorbing semiconductor, and germanium. Within the ultra-narrow bandwidth of the guided-mode resonance excited at 1.16 µm with a full width at half-maximum of 3.3 nm, we confirmed perfect absorption when light is incident from one of the two opposite directions. Excitation from the opposite direction resulted in perfect reflection. The thickness of the entire structure is limited to about one third the operating wavelength. Furthermore, due to the temperature tunability of silicon and germanium the thermo-optical sensitivity was found to be approximately 0.068 nm/K. In addition to this spectral tunability, our proposed device supports transparency windows with 80% transmission in the higher wavelength ranges. Our device is highly promising in the applications of thermo-tunable modulators and obtaining single frequency near-infrared signals from broadband sources.
在本信函中，我们通过数值模拟提出了一种温度可调的超窄带单向完美近红外辐射吸收器，该吸收器在较长波长的相邻光谱范围内具有高透射率。我们通过使用基于导模共振的光栅 - 波导超表面获得了这种功能，该超表面由硅、间隔电介质、吸收性半导体和锗组成。在1.16 µm激发的导模共振的超窄带宽内，半高宽为3.3 nm，当光从两个相反方向之一入射时，我们证实了完美吸收。从相反方向激发则导致完美反射。整个结构的厚度限制在约三分之一的工作波长。此外，由于硅和锗的温度可调性，热光灵敏度约为0.068 nm/K。除了这种光谱可调性外，我们提出的器件在较高波长范围内支持透射率为80%的透明窗口。我们的器件在热可调调制器的应用以及从宽带源获得单频近红外信号方面极具前景。
