Journal article
MHz-repetition-rate, sub-mW, multi-octave THz wave generation in HMQ-TMS
Department of Photonics Engineering, Technical University of Denmark1
Ultrafast Infrared and Terahertz Science, Department of Photonics Engineering, Technical University of Denmark2
Technical University of Denmark3
Ajou University4
Zurich University of Applied Sciences5
Korea Advanced Institute of Science and Technology6
Center for Nanostructured Graphene, Centers, Technical University of Denmark7
We demonstrate the first megahertz (MHz) repetition-rate, broadband terahertz (THz) source based on optical rectification in the organic crystal HMQ-TMS driven by a femtosecond Yb:fibre laser. Pumping at 1035 nm with 30 fs pulses, we achieve few-cycle THz emission with a smooth multi-octave spectrum that extends up to 6 THz at -30 dB, with conversion efficiencies reaching 10-4 and an average output power of up to 0.38 mW.We assess the thermal damage limit of the crystal and conclude a maximum fluence of ∼1.8 mJ cm-2 at 10 MHz with a 1/e2 pump beam diameter of 0.10 mm.
We compare the performance of HMQ-TMS with the prototypical inorganic crystal gallium phosphide (GaP), yielding a tenfold electric field increase with a peak on-axis field strength of 7 kV cm-1 and almost double the THz bandwidth. Our results further demonstrate the suitability of organic crystals in combination with fibre lasers for repetition-rate scaling of broadband, high-power THz sources for time-domain spectroscopic applications.
Language: | English |
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Year: | 2020 |
Pages: | 9631-9641 |
ISSN: | 10944087 |
Types: | Journal article |
DOI: | 10.1364/OE.386604 |
ORCIDs: | Buchmann, Tobias Olaf , Kelleher, Edmund J.R. , Zhou, Binbin , 0000-0003-0753-4841 and Jepsen, Peter Uhd |