High Speed Phenomena in Photonic Materials and Optical Bistability

H. Haug

D. Jäger

C. R. Paton, Z. Xie, J. M. Hvam

We have observed high-speed optical switching based on the optical bistability of CdSe at low temperatures due both to induced absorption and to dispersion changes. Using a streak camera to record the response of a thin CdSe platelet to high-intensity dye-laser pulses at near-band-gap energies, we have studied these phenomena on a picosecond time scale and measured switching times of several hundred picoseconds. We attribute our observations to nonlinearities caused by exciton interactions in the semiconductor material. Finally, we discuss the part played in these phenomena by thermal and other dynamic effects.

Y. Ron Shen

Takasumi Tanabe, Akihiko Shinya, Eiichi Kuramochi +2 more

We review our recent progress on all-optical switching and bistability using ultrahigh-Q photonic crystal nanocavities. We also discuss all-optical logic gate operations. Because photonic crystal nanocavities can strongly confine photons in a small area for a long time, light can efficiently interact with dipoles. As a result, optical nonlinearities occur at a very low input. Optical nonlinearities are essential as regards all-optical switching and bistability, because they dynamically change such material properties as refractive index. We demonstrate all-optical switching at an operating energy of less than 100 fJ, and bistable operation at less than ~100 μW. In addition, these devices are small and so can operate at a reasonably high speed (~100 ps).

Yasabu Ayall