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Ultrafast Terahertz Spectroscopy and Imaging


Three independent femtosecond laser systems are used for generating tunable ultrafast pulses in the mid-infrared (IR) and Terahertz (THz) spectral regions through the visible and ultraviolet (UV) to perform pump-probe time-resolved spectroscopy.  For pulse detection IR, THz and UV-visible multi-element focal plane array cameras and dispersive spectrometers for capturing images and transient spectra of samples with single laser pulses are available.  THz spectroscopy (covering 0.4 to 10 THz) is used to make accurate time-resolved electric field amplitude and phase measurements to extract charge carrier conductivity and mobility in various condensed-phase samples.


For time-resolved spectral measurements, apparatus includes two femtosecond solid-state laser systems pumped by CW Diode (YVO4) 20-femtosecond Ti: sapphire oscillators with 1 kilohertz Ti:Sapphire regenerative amplifiers.  These systems independently provide ca. 40 fs time resolution with 300 ps pump-probe delay.  They can also be electronically synchronized to provide up to millisecond pump-probe delay times.  Two mid-IR Optical Parametric Amplifiers (OPA) and various nonlinear crystals are employed for generating ultrafast pulses in the far-IR (THz) through UV.  In addition to gated diode and photomultiplier detectors, visible to near-IR CCD and phase-locked microbolometer (mid-IR to THz) multichannel detector arrays for directly capturing broadband transient spectra and mid-IR to THz wide-field images or by spectral up-converting images are available.

Time-resolved THz spectrometer (TRTS) for spectral/phase measurements of samples (from 0.2 to 10 THz; sub-picosecond resolution) and transient spectroscopy of molecular, photovoltaic polymers, and 2D materials characterization. Non-contact conductivity and mobility are directly evaluated with this all-optical apparatus.
Created May 3, 2011, Updated August 12, 2020