Role of Diffusion of the Inverted Population in the Generation of Induced Radiation

V. B. Krasovit︠s︡kiĭ, В.И. Курилко

А.В. Андреев, Yu A Il'inskiĭ, R. M. Khokhlov

B. P. Kaulakis

It was only recently established that the ubiquitous black-body radiation plays an important role in the spectroscopy of Rydberg atoms even at room temperature. 1.2 Black-body radiation causes shifts in the energy of atomic levels,2 induces transitions between atomic states,2 causes photoionization of Rydberg atoms,3 and affects the population of highly excited states in the recombination of ions.4•5 We will show that black-body radiation also causes diffusive ionization of Rydberg atoms and ions. Under certain conditions, the principal condition among which is the collision-induced mixing of levels in I, the diffusion process resulting from black-body radiation is the basic mechanism for the ionization of Rydberg atoms.

Anastasia S. Chervinskaya, Dmitrii L. Dorofeev, B. A. Zon

Abstract Redistribution of population of Rydberg states and ionization of an atom as a result of multistep cascade transitions between states induced by radiation with continuous spectrum are analyzed. Analysis is carried out both by straightforward numerical solution of kinetic equations governing state populations and by using the diffusion approximation based on the Fokker–Planck equation. Using an example of a sodium atom exposed to radiation with rectangular spectrum as an example, we demonstrate good agreement between the diffusion approximation and numerical solution to kinetic equations. Estimates for state populations, ionization rate, and minimum spectral density of radiation required for achieving considerable ionization are obtained within the framework of the diffusion approximation.

B.I. Bondarev

Kim G Folin, V. V. Antsiferov