Abstract-Boosting terahertz-radiation power with two-color circularly polarized midinfrared laser pulses

V. A. Tulsky, M. Baghery, U. Saalmann, and S. V. Popruzhenko

https://journals.aps.org/pra/abstract/10.1103/PhysRevA.98.053415

A way to considerably enhance terahertz radiation, emitted in the interaction of intense midinfrared laser pulses with atomic gases, in both the total energy and the electric-field amplitude is suggested. The scheme is based on the application of a two-color field consisting of a strong circularly polarized midinfrared pulse with wavelengths of $1.6–4\mu m$ and its linearly or circularly polarized second harmonic of lower intensity. By combining the strong-field approximation for the ionization of a single atom with particle-in-cell simulations of the collective dynamics of the generated plasma, it is shown that the application of such two-color circularly polarized laser pulses may lead to an order-of-magnitude increase in the energy emitted in the terahertz frequency domain as well as in a considerable enhancement in the maximal electric field of the terahertz pulse. Our results support recently reported experimental and numerical findings.

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Abstract-Control of terahertz photoelectron currents generated by intense two-color laser radiation interacting with atoms

S. V. Popruzhenko and V. A. Tulsky

Phys. Rev. A 92, 033414 – Published 14 September 20

http://journals.aps.org/pra/abstract/10.1103/PhysRevA.92.033414

Using the strong-field approximation, a net photoelectron current, generated due to the interaction of an intense two-color laser field consisting of the fundamental and the second harmonic of infrared laser radiation with an atom, is found. The focus is on the case in which neither of the two field components can be treated perturbatively. The dependence of the current on the ratio of the harmonic amplitudes and their relative phase is studied and parameters maximizing the current are specified.

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