Field cancellation by a two-level atom in a multimode cavity driven by a time-dependent field

Abstract

We investigate the behavior of a two-level atom in a multimode cavity driven from the side by a time-dependent field. The time-dependent fields we have looked at are (i) pure amplitude modulated, (ii) pure frequency modulated, (iii) single sideband, and (iv) general three-mode fields. Each of these fields results in two (for the single-sideband case) or three modes separated by the modulation frequency. We find that when the driving field mode spacing is a multiple of the cavity mode spacing, the multimode cavity field created by the driven two-level atom becomes exactly 180\ifmmode^\circ\else\textdegree\fi{} out of phase with the external driving field in steady state. This results in a zero net field at the position of the atom and, hence, the atom remains unexcited regardless of the strength of the external driving field. This is very reminiscent of the field-induced transparency effect as described by Cardimona et al. [J. Phys. B 15, 55 (1982)] in which the various dipole transitions of a multilevel atom dressed by a coherent field are driven 180\ifmmode^\circ\else\textdegree\fi{} out of phase with each other, producing a zero net fluorescence. We also show that, in the limit of an infinite cavity, the multimode equations reduce to the neoclassical equations of Stroud and Jaynes [Phys. Rev. A 1, 106 (1970)].