Abstract-Terahertz wave generation from liquid nitrogen

Alexei V. Balakin, Jean-Louis Coutaz, Vladimir A. Makarov, Igor A. Kotelnikov, Yan Peng, Peter M. Solyankin, Yiming Zhu, and Alexander P. Shkurinov

Fig. 1. Experimental setup. M–dielectric mirror; MM–metallic mirror; BS–beam splitter; 𝜆/2$\lambda /2$–half-wave phase plate; L–lens; PM–off-axis parabolic mirror; BBO–β$\mathrm{\beta }$-barium borate crystal.

https://www.osapublishing.org/prj/abstract.cfm?uri=prj-7-6-678

We present the results of research carried out for the first time, to the best of our knowledge, on the generation of terahertz radiation under the action of “single-color” and “dual-color” high-power femtosecond laser pulses on liquefied gas–liquid nitrogen. Our experimental results supported by careful theoretical interpretation showed clearly that under femtosecond laser radiation, liquid and air emit terahertz waves in a very different way. We assumed that the mobility of ions and electrons in liquid can play an essential role, forming a quasi-static electric field by means of ambipolar diffusion mechanism.

© 2019 Chinese Laser Press

Abstract-Abstract-Interaction of High-Intensity Femtosecond Radiation With Gas Cluster Beam: Effect of Pulse Duration on Joint Terahertz and X-Ray Emission

 Alexei V. Balakin ,  Murat S. Dzhidzhoev ,   Vyacheslav M. Gordienko ,  Mikhail N. Esaulkov ,     Nikolay A. Kuzechkin , 

  Irina A. Zhvaniya ,   Konstantin A. Ivanov ,  Igor A. Kotelnikov ,

 Ilya A. Ozheredov ,   Vladislav Y. Panchenko 

 Mikhail B. Smirnov ,  Peter M. Solyankin ,   Alexander P. Shkurinov

 Andrey B. Savel’ev 

http://ieeexplore.ieee.org/document/7740088/

This paper studies the phenomenon of joint generation of terahertz (THz) and X-ray radiation in the argon nanocluster jet under the action of high-power femtosecond laser pulse in both the single-color and dual-color regimes. It was discovered that in a gas cluster beam the pulse duration affects the properties of THz and X-ray emission differently. For the same given total energy of optical pulse in the dual-color excitation regime of cluster medium, more than a five times increase of THz radiation power was observed in comparison with the single-color regime, while the conversion efficiency to the argon X-ray K-line reached 7 × 10-6 and remained unchanged. The possibility of separation of contributions of different beam components into the THz signal was demonstrated experimentally, using contributions from clusters and nonclustered gas as an example. We suggest an interpretation of experimental results based on a theoretical model of cluster ionization that self-consistently predicts the level and dynamics of ionization and electron temperature in the clusters.