Subpicosecond Optical Switching with a Negative Index Metamaterial

We demonstrate a nanoscale subpicosecond (ps) matamaterial device capable of terabit/second all-optical communication in the near-IR. The 600 fs response, 2 orders of magnitude faster than previously reported is achieved by accessing a previously unused regime of light-injection level, subpicosecond carrier dynamics In the alpha-Si dielectric layer of the metamaterial. Further, we utilize a previously unrecognized, higher-order, shorter-wavelength negative-index resonance in the fishnet structure, thereby extending device functionality (via structural tuning of device dimensions) over 1.0-2.0 mu m. The pump energy required to modulate a single bit is only 3 nJ over our current 700 mu m(2) area device and can be easily scaled into the picoJoule regime with smaller cross sectional areas.