Ultrafast nonlinear optical tuning of photonic crystal cavities

The authors demonstrate fast (up to 20 GHz), low-power (60 fJ, 3 ps pulses) modulation of photonic crystal cavities in GaAs containing InAs quantum dots. Rapid modulation through blueshifting of the cavity resonance is achieved via free-carrier injection by an above-band picosecond laser pulse. Slow tuning by several linewidths due to laser-induced heating is also demonstrated.(c) 2007 American Institute of Physics.