#  Terahertz Time-Resolved Spectroscopy  

 



   ![Terahertz Box](/sites/g/files/omnuum1256/files/styles/hwp_1_1__720x720_scale/public/2024-12/IMG_20230323_181423_HDR.jpg?itok=fzCv_gGe) 

 

Terahertz (THz) time-resolved spectroscopy is a powerful tool for probing the electromagnetic properties of quantum materials within the THz frequency range (0.1 to 10 THz), encompassing energy scales characteristic of collective excitations such as plasmons, phonons, magnons, spinons, excitons, and superconducting Cooper pairs. Unlike Fourier transform spectroscopy, which operates in the frequency domain, time-resolved THz spectroscopy measures the electric field of ultrashort THz pulses directly in the time domain. This approach enables simultaneous extraction of the real and imaginary parts of optical response functions, such as refractive index and optical conductivity, with sub-picosecond resolution. It is uniquely suited to uncover the interplay between charge carriers, lattice vibrations, and magnetic or orbital degrees of freedom.

Our group leverages state-of-the-art single-shot THz detection systems combined with intense ultrashort far- and mid-infrared pump fields to perform advanced pump-probe experiments. We generate THz pulses through optical rectification in nonlinear crystals and detect them via electro-optic sampling. Conventional sampling schemes sequentially measure each point of the time-dependent THz field using an infrared probe pulse. Our setup improves upon this scheme by employing an echelon mirror to produce multiple temporally shifted copies of the probe pulse, allowing for simultaneous imaging of the full THz field profile on a linear detector. This innovation significantly enhances both the speed and accuracy of the technique, enabling precise tracking of ultrafast photoinduced dynamics.