Generating and shaping light in the THz frequency range

Abstract

With the tremendous development of ultrafast lasers we are provided with a tool for efficient wavelength conversion. Down conversion allows generation of mid-infrared and THz light and provides in addition also the ability to control the phase. This additional control knob is a new feature for optical experiments which we are just beginning to use. I will show a few experiments with semiconductor nanostructures and quantum cascade lasers where the phase information allows observing physical processes directly; this includes population transfer, amplification, and short pulse formation. In addition to the phase information, down conversion and quantum cascade lasers provide us with very large bandwidth- spanning more than one octave. Handling these bandwidths is an interesting challenge and also extremely attractive for new optical methods like frequency comb sensing.