Harmonic emission by a 1-d atomic model

Pooja Nadkarni Singh, Yuri V. Rostovtsev

Alexander Andkerson, Yuri V. Rostovtsev

Wilhelm Becker, S. Long, J. K. Mclver

Abstract The emission of very high harmonics of a laser field irradiating a model atom defined by a three-dimensional delta function is considered and several nonperturbative features of the harmonic spectrum are discussed.

Saverio Bivona, R. Burlon, C. Leone

We show that the parity of the order of the harmonics generated by a bichromatic field with commensurate frequencies may be related to the invariance properties of the time-dependent Hamiltonian with respect to some suitable transformations. To simplify the mathematical treatment, we have used a simple model atom to perform calculations that show the effects of the relative phase of the driving fields. Harmonic generation has been described as a two-step process that involves replicas of the Stark levels. In agreement with other previous treatments in which other model atoms were used, we have found that a small contamination of the fundamental harmonic can produce significant modifications of the emission spectra.

Emilio Fiordilino, Gianfranco Orlando, Marvin H. Mittleman

Victor A Malyshev, Pablo Moreno

We discuss the possibility of producing harmonics while the process of collective spontaneous emission (superradiance) takes place in a solid. Self correlations of dipole radiators induced by the emitted field lead to a reduction of the emission time and consequently to an increase of the intensity. Estimations of the superradiant energy flux show that, for crystalline densities of radiators, this flux may be comparable with the atomic unit. This assures the highly nonlinear behavior necessary to observe a pulse of high harmonics during superradiant pulse. We apply the Floquet–Bloch expansion to analyze the features of harmonic production in the framework of the two-level model.