A photon accelerator -- Large blueshifting of femtosecond pulses in semiconductors

摘要

The availability of relatively high intensity (I > 10{sup 9}Wcm{sup {minus}2}) [but moderate ({approximately} nJ) total energy], femtosecond laser pulses with wavelengths ranging from the ultraviolet to the mid-infrared has opened the doors for a serious investigation of the nonlinear optical properties of matter on ultrashort time scales in a new parameter regime. Even small intensity-dependent nonlinearities can begin to play a major role in the overall electrodynamics, and in determining the fate of the propagating pulse. It is shown that a femtosecond pulse propagating near a two-photon transition in a semiconductor waveguide can undergo a large blueshift.