Ultra-broadband THz pulses with electric field amplitude exceeding 100 kV/cm at a 200 kHz repetition rate

• Main Authors: Apretna, T. (Author), Boulier, T. (Author), Dhillon, S. (Author), Hanna, M. (Author), Mangeney, J. (Author), Nilforoushan, N. (Author), Song, C. (Author), Tignon, J. (Author)
• Format: Article
• Language: English
• Published: NLM (Medline) 2022
• Online Access: View Fulltext in Publisher
• ISBN: 10944087 (ISSN)
• DOI: 10.1364/OE.453105

We demonstrate a table-top source delivering ultra-broadband THz pulses with electric field strength exceeding 100 kV/cm at a repetition rate of 200 kHz. The source is based on optical rectification of 23 fs pulses at 1030 nm delivered by a ytterbium-doped fiber laser followed by a nonlinear temporal compression stage. We generate THz pulses with a conversion efficiency of up to 0.11 % with a spectrum extending to 11 THz using a 1 mm thick GaP crystal and a conversion efficiency of 0.016 % with a spectrum extending to 30 THz using a 30 µm thick GaSe crystal. The essential features of the emitted THz pulse spectra are well captured by simulations of the optical rectification process relying on coupled nonlinear equations. Our ultrafast laser-based source uniquely satisfies an important requirement of nonlinear THz experiments, namely the emission of ultra-broadband THz pulses with high electric field amplitudes at high repetition rates, opening a route towards nonlinear time-resolved THz experiments with high signal-to-noise ratios.