Single-shot terahertz time-domain spectrometer using 1550 nm probe pulses and diversity electro-optic sampling

• Published in: Optics express Vol. 31; no. 19; pp. 31072 - 31081
• Main Authors: Roussel, E., Szwaj, C., Di Pietro, P., Adhlakha, N., Cinquegrana, P., Veronese, M., Evain, C., Di Mitri, S., Perucchi, A., Bielawski, S.
• Format: Journal Article
• Language: English
• Published: Optical Society of America - OSA Publishing 11.09.2023
• Subjects: Optics; Physics
• ISSN: 1094-4087; 1094-4087
• DOI: 10.1364/OE.498726

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, 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 2.5 THz bandwidth with a maximum dynamic range reaching up to 25 dB. 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.