"Non-Linear Optical Processes in ZnTe Using Intense Coherent THz Pulses at the NSLS SDL Linac"

Yuzhen Shen, Dario Arena, G. Lawrence Carr, Chi-Chang Kao, James B. Murphy, Xijie Wang, Takahiro Watanabe, and Xi Yang

Single-cycle THz pulses are generated by coherent transition radiation from subpicosecond relativistic electron bunches, which have energy up to 100uJ per pulse. The intense single-cycle THz pulses can induce nonlinear cross-phase modulation (XPM) in an electro-optic crystal via its strong electric field through the Pockels effect. In the spatial domain, this leads to focusing, defocusing and beam break-up of a co-propagating laser probe. While acting in the spectral and temporal domains, it induces frequency chirp, spectral broadening, and deformation of the probe pulse. The availability of intense single-cycle THz pulses opens the way to a new regime in ultrafast optics and nonlinear optics.