Department of Electrical Engineering, Columbia University, New York, New York 10027, USA.
Nano Lett. 2013 Feb 13;13(2):691-6. doi: 10.1021/nl304357u. Epub 2013 Jan 18.
We demonstrate high-contrast electro-optic modulation of a photonic crystal nanocavity integrated with an electrically gated monolayer graphene. A silicon air-slot nanocavity provides strong overlap between the resonant optical field and graphene. Tuning the Fermi energy of the graphene layer to 0.85 eV enables strong control of its optical conductivity at telecom wavelengths, which allows modulation of cavity reflection in excess of 10 dB for a swing voltage of only 1.5 V. The cavity resonance at 1570 nm is found to undergo a shift in wavelength of nearly 2 nm, together with a 3-fold increase in quality factor. These observations enable a cavity-enhanced determination of graphene's complex optical sheet conductivity at different doping levels. Our simple device demonstrates the feasibility of high-contrast, low-power, and frequency-selective electro-optic modulators in graphene-integrated silicon photonic integrated circuits.
我们展示了与电栅控单层石墨烯集成的光子晶体纳米腔的高对比度电光调制。硅空气槽纳米腔提供了共振光场与石墨烯之间的强重叠。将石墨烯层的费米能调谐到 0.85eV，可使其在电信波长下的光学电导率得到强有力的控制，从而使腔反射的调制超过 10dB，仅需 1.5V 的摆幅电压。在 1570nm 的腔共振处，发现其波长发生了近 2nm 的移动，同时品质因数增加了 3 倍。这些观察结果使我们能够在不同掺杂水平下通过腔增强来确定石墨烯的复光学面电导率。我们的简单器件展示了在石墨烯集成硅光子集成电路中实现高对比度、低功耗和频率选择性电光调制器的可行性。
