High-field terahertz spectroscopy of semiconductor quantum structures

This seminar gives an overview on recent experimental studies involving terahertz (THz) and mid-infrared radiation from the free-electron laser facility FELBE in Dresden, Germany. In particular, cyclotron resonance spectroscopy and aperture-less near-field microscopy will be addressed as examples for linear measurements. Moreover, nonlinear THz photocurrents originating from two-photon excitation between subbands in semiconductor quantum wells allow for measurements of intersubband relaxation and dephasing times and for quadratic autocorrelation of THz pulses. The final part of this talk will concentrate on nonlinear two-color THz spectroscopy, in particular THz sideband generation and coherent dynamics involving excitons dressed by strong THz beams.