Electrically Tunable Metasurface Perfect Absorbers for Ultrathin Mid-Infrared Optical Modulators
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- 作者：Yu Yao ; Raji Shankar ; Mikhail A. Kats ; Yi Song ; Jing Kong ; Marko Loncar ; Federico Capasso
- 刊名：Nano Letters
- 出版年：2014
- 出版时间：November 12, 2014
- 年：2014
- 卷：14
- 期：11
- 页码：6526-6532
- 全文大小：357K
- ISSN：1530-6992
文摘
Dynamically reconfigurable metasurfaces open up unprecedented opportunities in applications such as high capacity communications, dynamic beam shaping, hyperspectral imaging, and adaptive optics. The realization of high performance metasurface-based devices remains a great challenge due to very limited tuning ranges and modulation depths. Here we show that a widely tunable metasurface composed of optical antennas on graphene can be incorporated into a subwavelength-thick optical cavity to create an electrically tunable perfect absorber. By switching the absorber in and out of the critical coupling condition via the gate voltage applied on graphene, a modulation depth of up to 100% can be achieved. In particular, we demonstrated ultrathin (thickness < 位0/10) high speed (up to 20 GHz) optical modulators over a broad wavelength range (5鈥? 渭m). The operating wavelength can be scaled from the near-infrared to the terahertz by simply tailoring the metasurface and cavity dimensions.