ИСТИНА

New approach to the problem of generation and amplification of electromagnetic radiation of the terahertz frequency band in strongly nonequilibrium plasma channels created by high-intensity laser radiation in gases is discussed. This approach is based on the two-color laser induced THz background production in different nonlinear processes during the pulse of in the after-pulse regime and its further amplification in the plasma channel with population inversion formed by the laser pulse [1]. Different mechanisms of THz radiation amplification in the laser plasma channel will be analyzed [2,3]. Special attention will be paid to the case of nearly-resonant background formation in aluminum vapor irradiated by Ti-Sa laser pulse and its second harmonics. [1] Bogatskaya A. V., Volkova E. A., Popov A. M. Generation and amplification of sub-THz radiation in a plasma of rare gases formed by two-color femtosecond laser pulse // Laser Physics Letters. — 2018. — Vol. 15, no. 6. — P. 065301. [2] Bogatskaya A. V., Popov A. M. On the possibility of the amplification of subterahertz electromagnetic radiation in a plasma channel created by a high-intensity ultrashort laser pulse // JETP Letters. — 2013. — Vol. 97, no. 7. — P. 388–392. [3] Bogatskaya A. V., Volkova E. A., Popov A. M. Amplification and lasing in a plasma channel formed in gases by an intense femtosecond laser pulse in the regime of interference stabilization // Laser Physics. — 2016. — Vol. 26, no. 1. — P. 0153