Rohit P Prasankumar

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We demonstrate a nanoscale, subpicosecond (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, subpicosecond carrier dynamics in the alpha-Si dielectric layer of the(More)
The mechanisms producing strong coupling between electric and magnetic order in multiferroics are not always well understood, since their microscopic origins can be quite different. Hence, gaining a deeper understanding of magnetoelectric coupling in these materials is the key to their rational design. Here, we use ultrafast optical spectroscopy to show(More)
We study the nonlinear optical response of a fishnet structure-metamaterial all-optical switching device that exhibits two near-infrared negative-index resonances. We study and compare the nonlinear optical response at both resonances and identify transient spectral features associated with the negative index resonance. We see a significantly stronger(More)
Ultrafast differential transmission spectroscopy is used to explore temperature-dependent carrier dynamics in an InAs/InGaAs quantum dots-in-a-well heterostructure. Electron-hole pairs are optically injected into the three dimensional GaAs barriers, after which we monitor carrier relaxation into the two dimensional InGaAs quantum wells and the zero(More)
Currently, high-energy pulses as short as 4 to 5 fs at a center wavelength of 800 nm are generated by external compression at kHz and 1 MHz repetition rates, respectively. 6 These pulse widths correspond to less than two optical cycles. The shortest pulses generated at the higher repetition rate of 100 MHz have been 6.5 fs 7 and 7 fs. 8 For high-resolution(More)
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