Subpicosecond optical switching with a negative index metamaterial

We demonstrate a nanoscale, subplcosecond (ps) metamaterial 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 high-injection level, subplcosecond carrier dynamics in the α-Si dielectric layer of the metamaterial. Further, we utilize a previously unrecognized, higherorder, shorter-wavelength negative-index resonance in the fishnet structure, thereby extending device functionality (via structural tuning of device dimensions) over 1.0-2.0 μm. The pump energy required to modulate a single bit is only 3 nJ over our current 700 μm² area device and can be easily scaled into the picoJoule regime with smaller cross sectional areas.