Exponential gain and self-bunching in a collective atomic recoil laser

Abstract

%'e show how a collection of noninverted two-level systems, under the action of a quasiresonant pump field, can produce an exponential amplification of a probe signal through the mechanism of a dynamical instability with spatial self-bunching in a way very similar to that experienced by a high-gain freeelectron laser. We offer a detailed description of this phenomenon, specify the conditions under which it takes place, and sketch possible experimental parameters for its observation in a gaseous medium. PACS number(s): 42.55. -f, 42.50. -p, 32.80.Pj

Collective atomic recoil lasing including friction and diffusion effects

“…and |a| 2 ∝ P s /N , where P s is the scattered light power, then P s ∝ N 4/3 as in the usual CARL [1,2,3]. Conversely, for κ ≫ 1 ('bad-cavity' limit) we obtain | p | ≪ κ and |a| 2 ≈ 1/κ 2 , so that the scattered power P s is proportional to N 2 , i.e.…”

“…However, the fact that the collective atomic centre-of-mass motion of atoms can strongly influence the evolution of optical fields has only received attention relatively recently [1,2,3,4]. Recent experimental studies involving large numbers of cold atoms in high-quality cavities [5,6,7] represent an important advance in this field, allowing detailed experimental studies of collective atom-light interaction dynamics.…”

“…This is a unique example of a steady-state superfluorescence, i.e. superradiance from an incoherently prepared atomic system.Our system consists of an ensemble of atoms backscattering a far-detuned pump field into a counterpropagating mode of a ring cavity, described by a set of equations derived by Bonifacio and coworkers [1,2,3]. The equations are here generalized to include a friction force, −γp, and a stochastic force, F (t), due to the presence of optical molasses:…”

“…Recent experimental studies involving large numbers of cold atoms in high-quality cavities [5,6,7] represent an important advance in this field, allowing detailed experimental studies of collective atom-light interaction dynamics. During these interactions both the mechanical effect of the cavity modes on the atomic motion and the driving of the cavity modes by the dynamic spatial distribution of atoms in the cavity must be described self-consistently and cannot be considered independently.A recent experiment by Kruse et al [5] represents the first unambiguous realization of the CARL model originally proposed by Bonifacio and coworkers [1], which describes collective backscattering of an optical pump field by a sample of cold atoms. Previous experiments on CARL have been performed in hot atomic vapours [8,9] where however the gain of the backward field can not be unambiguously attributed to atomic recoil.…”

“…A recent experiment by Kruse et al [5] represents the first unambiguous realization of the CARL model originally proposed by Bonifacio and coworkers [1], which describes collective backscattering of an optical pump field by a sample of cold atoms. Previous experiments on CARL have been performed in hot atomic vapours [8,9] where however the gain of the backward field can not be unambiguously attributed to atomic recoil.…”