Abstract

We study the influence of the polarization state of multi-color femtosecond laser pulses ionizing air or noble gases on the emitted terahertz radiation. A local-current model and plane wave evaluations predict a cross-over in the THz energy yields with increasing number of pump harmonics, for which circular laser polarization is more efficient for a few harmonics, and linear polarization is favorable for more than six pump colors. Comprehensive 3D numerical simulations of gas jet experiments confirm this property for singly and multiply ionized gases. Rotation of the THz polarization ellipse in the case of circular laser polarization is explained by phase shifts that may alter the phase angle between the harmonics.

© 2021 Optical Society of America

Wavelength scaling of terahertz pulse energies delivered by two-color air plasmas

A. Nguyen, K. J. Kaltenecker, J.-C. Delagnes, B. Zhou, E. Cormier, N. Fedorov, R. Bouillaud, D. Descamps, I. Thiele, S. Skupin, P. U. Jepsen, and L. Bergé
Opt. Lett. 44(6) 1488-1491 (2019)

Broadband terahertz generation by optical rectification of ultrashort multiterawatt laser pulses near the beam breakup threshold

M. M. Nazarov, P. A. Shcheglov, V. V. Teplyakov, M. V. Chashchin, A. V. Mitrofanov, D. A. Sidorov-Biryukov, V. Y. Panchenko, and A. M. Zheltikov
Opt. Lett. 46(23) 5866-5869 (2021)

Intensity modulated terahertz vortex wave generation in air plasma by two-color femtosecond laser pulses

Maksym Ivanov, Illia Thiele, Luc Bergé, Stefan Skupin, Danas Buožius, and Virgilijus Vaičaitis
Opt. Lett. 44(15) 3889-3892 (2019)

Coherently enhanced microwave pulses from midinfrared-driven laser plasmas

A. V. Mitrofanov, D. A. Sidorov-Biryukov, M. M. Nazarov, A. A. Voronin, M. V. Rozhko, A. B. Fedotov, and A. M. Zheltikov
Opt. Lett. 46(5) 1081-1084 (2021)

Laser filaments as pulsed antennas

Aleksei M. Zheltikov
Opt. Lett. 46(19) 4984-4987 (2021)