Programme

O.22 -- Oral, VCTP-45

Date: Wednesday, 14 October 2020

Time: 16:00 - 16:20

Online presentation

Wavelength dependence of high-order harmonic yields of Rydberg atom

Ngoc-Loan Phan (1), Cam-Tu Le (2), Van-Hoang Le (1)

(1) Ho Chi Minh City University of Education, Ho Chi Minh City, Vietnam (2) Ton Duc Thang University, Ho Chi Minh City, Vietnam

Currently, high-order harmonic generation (HHG), emitted by the atom/molecule-laser interaction, has been considered as the unique source for producing attosecond pulse, which is an effective tool for probing the ultrafast motion [1]⁠. Thus, it is necessary to enhance HHG energy. One of the methods is using a laser with a long wavelength [2]⁠ . However, it leads to rapidly reduce the HHG efficiency with the universal scaling law $λ^{-5}$ – $λ^{-6}$ with the wavelength λ [2]⁠ . Therefore, many efforts focus on trying to slow down the wavelength scaling law [3]⁠⁠. Adopting Rydberg atom, i.e. an atom in the coherent superposition state, can lead to a slow scaling law ~ $λ^{-2.8}$ [3]. This result is interesting and should be further investigated in detail. \\ In this report, we theoretically study the structure of the wavelength scaling law of HHG from an Rydberg atom. We found out that the scaling law of the Rydberg atom strongly oscillates with the wavelength. In addition, the oscillation depends on the frequency window to synthesis HHG yields, and also on the laser CEP. We attribute this property to the multi-node of the density population of the electron in the Rydberg state. \\ \\ [1] A. Baltuška, T. Udem, M. Uiberacker, M. Hentschel, E. Goulielmakis, C. Gohle, R. Holzwarth, V. S. Yakovlev, A. Scrinzi, T. W. Hänscht, and F. Krausz, Nature 421, 611 (2003).\\ [2] J. Tate, T. Auguste, H. G. Muller, P. Salières, P. Agostini, and L. F. DiMauro, Phys. Rev. Lett. 98, 013901 (2007).\\ [3] H. Du, S. Xue, H. Wang, Y. Wen, and B. Hu, J. Opt. Soc. Am. B 31, 1621 (2014).

Presenter: Phan Ngoc-Loan