Electromagnetic radiation in the terahertz (THz) frequency range is extensively used to study the dynamics of collective motions in solids and liquids or image optically non-transparent samples. The latter is gaining much attention in security and defense applications.
Femtosecond lasers are ideal tools to produce 1 – 30 THz pulses with the desired spectral bandwidth and pulse duration at substantial energy levels. Several laser-based THz generation techniques are available, one of the most common being optical rectification. This second‐order nonlinear optical process is a special case of difference‐frequency generation (DFG). It can be described as intrapulse DFG, where the spectral components with different angular frequencies from the laser pulse are mixed in a nonlinear crystal, thereby generating a new spectral component in the THz range.
Furthermore, THz pulses can be generated by laser excitation of photoconductive antenna or semiconductor surfaces, while one of the most intriguing techniques is plasma-based THz generation. In particular, using air/gas plasma for THz generation is advantageous due to the fact that, unlike nonlinear crystals and other bulk materials, gases do not suffer from damage threshold and are continuously renewable; thus, they can be pumped at extremely high intensities.
Compact and cost-efficient CARBIDE and PHAROS femtosecond lasers feature market-leading output parameters and a robust design attractive to both industrial and scientific customers. The laser output is compressible to sub-10 fs, enabling an efficient THz generation.
1.3% conversion efficiency terahertz source based on lithium niobate pumped by sub-millijoule ytterbium laser
L. Guiramand, J. E. Nkeck, X. Ropagnol, T. Ozaki, and F. Blanchard, in Optica High-brightness Sources and Light-driven Interactions Congress 2022, (Optica Publishing Group, 2022).
Near-optimal intense and powerful terahertz source by optical rectification in lithium niobate crystal
L. Guiramand, J. E. Nkeck, X. Ropagnol, T. Ozaki, and F. Blanchard, Photonics Research 2 (10), 340 (2022).
Classification of Analgesic Drugs in Primary Packaging by Applying Multivariate Methods to Terahertz Spectra
A. V. Lyakhnovich, G. V. Sinitsyn, M. A. Khodasevich, and D. A. Borisevich, Journal of Applied Spectroscopy 5 (88), 1008-1011 (2021).
Terahertz emission from ultrathin bismuth layers
J. Devenson, R. Norkus, R. Juškėnas, and A. Krotkus, 15 (46), 3681 (2021).
Terahertz Photoconductivity Spectra of Electrodeposited Thin Bi Films
I. Nevinskas, Z. Mockus, R. Juškėnas, R. Norkus, A. Selskis, E. Norkus, and A. Krotkus, 12 (14), 3150 (2021).
Terahertz pulse emission from photoexcited bulk crystals of transition metal dichalcogenides
I. Nevinskas, R. Norkus, A. Geižutis, L. Kulyuk, A. Miku, K. Sushkevich, and A. Krotkus, Journal of Physics D: Applied Physics 11 (54), 115105 (2021).
Efficient terahertz generation and detection in cadmium telluride using ultrafast ytterbium laser
X. Ropagnol, M. Matoba, J. E. Nkeck, F. Blanchard, E. Isgandarov, J. Yumoto, and T. Ozaki, Applied Physics Letters 18 (117), 181101 (2020).
Quantum dot photoconductive antenna-based compact setups for terahertz spectroscopy and imaging
A. A. Gorodetsky, A. Yadav, S. V. Smirnov, N. Bazieva, and E. U. Rafailov, in Terahertz Emitters, Receivers, and Applications XI, M. Razeghi, and A. N. Baranov, eds. (SPIE, 2020).
Sub-cycle atomic-scale forces coherently control a single-molecule switch
D. Peller, L. Z. Kastner, T. Buchner, C. Roelcke, F. Albrecht, N. Moll, R. Huber, and J. Repp, Nature 7823 (585), 58-62 (2020).
Spectral dependence of THz emission from InN and InGaN layers
R. Norkus, R. Aleksiejūnas, A. Kadys, M. Kolenda, G. Tamulaitis, and A. Krotkus, Scientific Reports 1 (9) (2019).