Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Lasing without inversion experiments and theory

Marlan O. Scully, Michael Fleischhauer, Edward S. Fry, Mikhail D. Lukin, Dmitri E. Nikonov, Gunasiri G. Padmabandu, Ulrich W. Rathe

Published May 8, 1994• 0 citations
OpenAlex

Abstract

Quantum coherence and correlations in atomic systems have many interesting and potentially useful consequences, such as cancellation of absorption, lasing without inversion, and enhancement of the index of refraction without absorption.

Related papers

Lasing without inversion and other effects of atomic coherence and interference

Marlan O. Scully, Muhammad Suhail Zubairy

Quantum coherence and correlations in atomic and radiation physics have led to many interesting and unexpected consequences. For example, an atomic ensemble prepared in a coherent superposition of states yields the Hanle effect, quantum beats, photon echo, self-induced transparency, and coherent Raman beats. In fact, in Section 1.4, we saw that the quantum beat effect provides one of the most compelling reasons for quantizing the radiation field. A further interesting consequence of preparing an atomic system in a coherent superposition of states is that, under certain conditions, it is possible for atomic coherence to cancel absorption. Such atomic states are called trapping states †. The observation of nonabsorbing resonances via atomic coherence and interference impacts on the concepts of lasing without inversion (LWI),‡ enhancement of the index of refraction accompanied by vanishing absorption, and electromagnetically induced transparency. In lasing without inversion, the essential idea is the absorption cancellation by atomic coherence and interference. This phenomenon is also the essence of electromagnetically induced transparency. Usually this is accomplished in three-level atomic systems in which there are two coherent routes for absorption that can destructively interfere, thus leading to the cancellation of absorption. A small population in the excited state can thus lead to net gain. A related phenomenon is that of resonantly enhanced refractive index without absorption in an ensemble of phase-coherent atoms ( phaseonium ). In a phaseonium gas with no population in the excited level, the absorption cancellation always coincides with vanishing refractivity.

Cambridge University Press eBooks•Sep 4, 1997•11 citations

Near dipole-dipole effects in lasing without inversion: An enhancement of gain and absorptionless index of refraction

Jonathan P. Dowling, Charles M. Bowden

We include the effect of density-dependent near dipole-dipole interactions in order to generalize the theory of a simple three-level system that exhibits lasing without inversion and an enhanced index of refraction at zero absorption. For certain values of atomic density, our generalized theory predicts a novel enhancement of inversionless gain and absorptionless index by more than 2 orders of magnitude.

Physical Review Letters•Mar 8, 1993•113 citations

Demonstration of lasers without inversion

Marlan O. Scully, Leo W. Hollberg, Mikhail D. Lukin +1 more

Summary form only given. Intensive theoretical work, carried out in the past decade, has indicated that optical properties of matter can be dramatically affected by atomic coherence and interference effects. In particular, atomic coherence and interference was shown to lead to such intriguing phenomena as electromagnetically induced transparency, lasing without population inversion (LWI), and resonant enhancement of refractive index accompanied by vanishing absorption. In the present paper we report the first experimental observation of LWI oscillation and the first demonstration of index enhancement.

Quantum Electronics and Laser Science Conference•Jun 7, 1996•0 citations

Atomic Coherence Effects in Quantum Optics: From Lasing Without Inversion and High Index Materials to Spontaneuos Cancellation

Marlan O. Scully

APS•Oct 1, 1997•0 citations

Quantum interference in three-level atomic configuration and double slit

J Saikia, A Dahal, SS Borah +3 more

The main idea of lasing without inversion is the cancellation of absorption which leads to amplification (and laser) even if population inversion is not present. Such a situation is realized in three level atomic configurations where two coherent atomic transitions interfere destructively. In the present work, we describe the salient features where the situation is analogous to the double slit experiment.

International Journal of Physics and Mathematics•Jan 1, 2024•0 citations

Lasing without inversion and enhancement of the index of refraction via interference of incoherent pump processes

Michael Fleischhauer, Christoph H. Keitel, Marlan O. Scully +1 more

Optics Communications•Jan 1, 1992•141 citations
Quantum coherence and correlations in atomic and radiation physics have led to many interesting and unexpected consequences. For example, an atomic ensemble prepared in a coherent superposition of states yields the Hanle effect, quantum beats, photon echo, self-induced transparency, and coherent Raman beats. In fact, in Section 1.4, we saw that the quantum beat effect provides one of the most compelling reasons for quantizing the radiation field. A further interesting consequence of preparing an atomic system in a coherent superposition of states is that, under certain conditions, it is possible for atomic coherence to cancel absorption. Such atomic states are called trapping states †. The observation of nonabsorbing resonances via atomic coherence and interference impacts on the concepts of lasing without inversion (LWI),‡ enhancement of the index of refraction accompanied by vanishing absorption, and electromagnetically induced transparency. In lasing without inversion, the essential idea is the absorption cancellation by atomic coherence and interference. This phenomenon is also the essence of electromagnetically induced transparency. Usually this is accomplished in three-level atomic systems in which there are two coherent routes for absorption that can destructively interfere, thus leading to the cancellation of absorption. A small population in the excited state can thus lead to net gain. A related phenomenon is that of resonantly enhanced refractive index without absorption in an ensemble of phase-coherent atoms ( phaseonium ). In a phaseonium gas with no population in the excited level, the absorption cancellation always coincides with vanishing refractivity.
Summary form only given. Intensive theoretical work, carried out in the past decade, has indicated that optical properties of matter can be dramatically affected by atomic coherence and interference effects. In particular, atomic coherence and interference was shown to lead to such intriguing phenomena as electromagnetically induced transparency, lasing without population inversion (LWI), and resonant enhancement of refractive index accompanied by vanishing absorption. In the present paper we report the first experimental observation of LWI oscillation and the first demonstration of index enhancement.