Terahertz time domain spectrometer to characterize nonlinear materials for efficient terahertz generation

Strong-field THz radiation is essential to several applications such as terahertz (THz) time-resolved spectroscopy and electron acceleration.Optical rectification in nonlinear materials such as lithium niobate (LN), lithium tantalate (LT) and serveral organic crystals, holdpromise in energy scalabilty of single-cycle THz generation. Fundamental properties of these materials are yet unexplored or poorly reportedin this wavelength regime. We investigate the spectroscopic properties of nonlinear materials employed for broadband THz generation withan in-house THz time-domain spectrometer (THz-TDS) -based on a 85 MHz Ti:Sapphire oscillator with 400 mWaverage power and 50 fs pulseduration. We employ our THz-TDS to study the absorptive, reflective, and amplitude/phase properties of LN and LT at cryogenic- and roomtemperature.We also report experimental results of strong-field THz generation optimized from our nonlinear materials study