Physical Review A

Gain without population inversion in two-level atoms

Helen K. Holt

Published Sep 1, 1977• 23 citations

Abstract

For the case in which laser radiation interacts with two levels of an atom, it is shown that there can be gain, even when there is no population inversion, because of recoil effects. The effect of recoil on certain precision measurements is also shown.

DOI: 10.1103/physreva.16.1136

Related papers

Collective atomic recoil laser (CARL) optical gain without inversion by collective atomic recoil and self-bunching of two-level atoms

R. Bonifacio, L. De Salvo

Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated EquipmentMar 1, 1994172 citations

Gain without inversion in four level atoms using pulsed lasers

Steve R. Wilkinson, Arlie V. Smith

We present results of a numerical calculation of gain without inversion in the transient regime. We show that atomic coherence and gain without population inversion can be induced on time scales short compared to atomic radiative lifetimes. We also describe the process in terms of transient dressed states.

Quantum Optics Journal of the European Optical Society Part BAug 1, 19943 citations

Lasing without inversion and origin of gain in a Λ system

Deng-Yu Zhang

A three-level Λ-type atomic system is pumped by an incoherent radiation field. The system lases without population inversion in the steady state. We analyze the inversionless gain and origin of the gain.

Acta Physica Sinica (Overseas Edition)Feb 1, 19970 citations

Amplification and Lasing without Inversion

Paul Mandel

When an atomic system interacts with light, it can amplify the electromagnetic radiation when gain exceeds loss. This requires that transitions from the upper level to the lower level prevail over the transitions from the lower level to the upper level. If one deals with a two-level system, the only way to obtain amplification is to create a state of population inversion, i.e. the upper level must be more densely populated that the lower level. "Lasing without inversion" may be possible when part of the atoms are trapped, which removes them from the subspace of states with which the upper level can have transitions. This chapter determines to what extent population inversion is necessary to achieve amplification. Independently, amplification without inversion and lasing without inversion were predicted by Harris using a different type of atomic interference. The amplification threshold has a number of features that are reminiscent of the laser threshold.

CRC Press eBooksMay 4, 20180 citations

Near lasing in an ensemble of two-level atoms

Yifu Zhu, A. Lezama, THOMAS W. MOSSBERG

Two-level atoms (in free space) cannot be maintained in a state of steady-state inversion. Although this fact may seem to preclude the possibility of producing a two-level-atom laser, It is well known that strongly driven two-level atoms exhibit gain (and loss) at certain frequencies in the vicinity of the excitation frequency.1 Inside an optical cavity the optical gain may be larger than the losses, and laser oscillation should occur with an ensemble of two-level atoms as the active medlum.2

Quantum Electronics and Laser Science ConferenceApr 24, 19890 citations

Coherent and Collective Interactions of Particles and Radiation Beams: Varenna on Lake Como, Villa Monastero, 11-21 July 1995

Alain Aspect, William A. Barletta, R. Bonifacio +1 more

This work focuses on fundamental theoretical and experimental aspects of relativistic beam physics, recoil, and cooling phenomena in atomic and ion beams and traps, emphasizing coherence and collective effects. The physics of atomic laser and free electron laser, and the development of a bridge between them through the mechanism of the so-called recoil induced gain mechanism, is also examined, as are the links between relativistic beam physics and atomic laser physics. Topics include: laser cooling of trapped ions; optical lattices; spatio-temporal instabilities in optical systems; coherence in atom optics; coherent population trapping; two-level gain and collective recoil-induced effects; high-gain free electron laser - theory, experiments and projects; cooling of ion beams in a storage ring; and experiments on dense laser-cooled stored ion beams.

Jan 1, 19970 citations