A single-shot terahertz time-domain spectrometer using 1550 nm probe pulses and diversity electro-optic sampling
preprintposted on 2023-07-17, 09:43 authored by Eleonore Roussel, Christophe Szwaj, Paola Di Pietro, Nidhi DHLAKHA, Paolo Cinquegrana, Marco Veronese, Clément Evain, Simone Di Mitri, Andrea Perucchi, Serge Bielawski
Classical terahertz spectroscopy usually requires the use of Fourier transform or Time-Domain Spectrometers. However, these classical techniques become impractical when using recent high peak power terahertz sources – based on intense lasers or accelerators – which operate at low repetition rate. We present and test the design of a novel Time-Domain Spectrometer (TDS), that is capable of recording a whole terahertz spectrum at each shot of the source, and that uses a 1550 nm probe fiber laser. Single-shot operation is obtained using chirped-pulse electro-optic sampling in Gallium Arsenide, and high bandwidth is obtained by using the recently introduced Diversity Electro-Optic Sampling (DEOS) method. We present the first real-time measurements of THz spectra at the TeraFERMI Coherent Transition Radiation source. The system achieves 4 THz bandwidth, and a 25 dB dynamic range. By reducing the required measurement time from minutes to a split-second, this strategy dramatically expands the application range of high power low-repetition rate THz sources.