A repository & source of cutting edge news about emerging terahertz technology, it's commercialization & innovations in THz devices, quality control, process control, medical diagnostics, security, astronomy, communications, graphene, metamaterials, CMOS, compressive sensing, 3d printing, and the Internet of Nanothings. NOTHING POSTED IS INVESTMENT ADVICE! REPOSTED COPYRIGHT IS FOR EDUCATIONAL USE.
Sunday, July 16, 2017
Abstract-MV/cm terahertz pulses from relativistic laser-plasma interaction characterized by nonlinear terahertz absorption bleaching in n-doped InGaAs
Sudipta Mondal, Hassan A. Hafez, Xavier Ropagnol, and Tsuneyuki Ozaki
We have developed a tabletop intense broadband terahertz (THz) source in the medium frequency range (≤ 20 THz) based on the interaction of a high-intensity femtosecond laser with solid targets at relativistic laser intensities. When an unpolished copper target is irradiated with a high-intensity femtosecond laser, a maximum of ~2.2 μJ of THz pulse energy is collected and detected with a calibrated pyroelectric detector. The THz spectrum was measured by using a series of bandpass filters, showing a bandwidth of ~7.8 THz full-width at half-maximum (FWHM) with a peak at ~6 THz. With tight focusing to reach high field strengths, we have demonstrated THz nonlinearity exemplified by THz absorption bleaching in a heavily n-doped InGaAs thin film, which enabled us to estimate the peak electric field of the THz pulses. We simulated the experimentally observed bleaching by employing a THz pulse having a bandwidth similar to that measured in our experiments and a temporal profile recoded in single-shot electro-optic detection. Through the simulations, we estimate a peak electric field associated with the THz pulses to be 2.5 MV/cm.