Superradiance in layers of excited classical and quantum oscillators

N. S. Ginzburg, Alexander S. Sergeev

N. S. Ginzburg, Alexander S. Sergeev

Iu. A. Il'Inskii, N. S. Maslova

Kensuke S. Ikeda, S. Sawada

Rostislav M. Arkhipov, Nikolay N. Rosanov

Abstract The possibility of generating extremely short pulses of terahertz (THz) radiation due to superradiance—collective spontaneous emission of a thin layer of a three-level resonant medium excited by a pair of attosecond (or femtosecond) pulses—is studied theoretically. The source of a terahertz pulse is a pulse of stopped nonlinear polarization of the medium, which arises in the interval between its excitation and deexcitation. The case of a three-level medium with equidistant energy levels (as in a quantum harmonic oscillator) the transition frequency of which lies in the THz range is considered. The influence of the populations of the excited levels of the medium on the shape of a terahertz superradiance pulse is discussed.

Rostislav M. Arkhipov, A. V. Pakhomov, Mikhail V. Arkhipov +1 more

Using the numerical solution of the system of equations for the amplitudes of bound states, together with the wave equation, we theoretically consider stopped polarization pulse superradiance upon excitation by a pair of half-period attosecond pulses in a thin layer of a five-level resonant medium, the parameters of which are the same as in a hydrogen atom. It is shown that in the case of a multilevel medium, at certain parameters of the exciting field, the superradiance pulse near the medium is also a single-cycle pulse, the shape of which is determined by the first time derivative of the stopped polarization pulse, as in the case when approximate low-level and classical models were used to describe the response of the medium. Keywords: superradiance, attosecond pulses, stopped polarization pulse, unipolar pulses, subcycle pulses.