THz time-domain spectroscopy (THz-TDS) with electro-optic detection

Summary form only given. THz-TDS has now been established as a powerful technique for THz (far-infrared) spectroscopy. To date, THz-TDS applications have predominantly utilized photoconductive antenna for the receiver. However, electro-optic (EO) THz receivers have demonstrated exceptionally high frequency performance, but without continuous spectral coverage due to the complications of strong absorption and dispersion of the electro-optic crystal, phase mismatch between the interrogating light pulse and the propagating THz pulse and a strong frequency dependence of the EO susceptibility. We present a frequency-domain theoretical description of the complete EO detection process, including a frequency-dependent EO nonlinearity. Our result, which only requires the evaluation of a Fourier integral, shows that THz-TDS is also applicable with EO detection, independent of the extensive time-domain pulse distortion of the actual EO measurement.