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

Physical Review Letters

Propagating, Optical-Pumping Wave Fronts

Natarajan D. Bhaskar, M. Hou, B Suleman, W. Happer

Published Aug 13, 1979• 24 citations
Publisher

Abstract

We have discovered a novel, spatially propagating wave front which is generated by laser pumping of an optically thick medium to a state of complete transparency. The wave front consists of a moving band of fluorescent light which marks the location of atoms which are being pumped. The wave-front velocity $v$, the photon flux ${I}_{0}$, the atomic number density $N$, and the number $n$ of photons absorbed per atom are related by $v={I}_{0}\ifmmode\times\else\texttimes\fi{}{(\mathrm{Nn})}^{\ensuremath{-}1}$.

DOI
10.1103/physrevlett.43.519

Related papers

Front propagation in evanescent media

Μ. Büttiker, H. Thomas

We investigate the time evolution of waves in evanescent media generated by a source within this medium and observed at some distance away from the location of the source. The aim is to find a velocity which describes a causal process and is thus, for a medium with relativistic dispersion, limited by the velocity of light. For a source with a sharp onset in time, the wave function consists of a forerunner generated by the onset of the source, and of a monochromatic front. The forerunner is dominated by a frequency which decreases with time, and the monochromatic front carries the oscillation frequency of the source into the evanescent medium. For a medium with Schrödinger-like dispersion the velocity of the front is infinite and the monochromatic front propagates with a velocity which is in agreement with the traversal time for tunneling. In the relativistic case the forerunners travel with the velocity of light and the velocity the monochromatic front is smaller than the velocity of light and only for special energies equal to the velocity of light. For sources with a sharp onset, the forerunners are not attenuated and in magnitude far exceed the monochromatic front. This renders the detection of the monochromatic front difficult. To avoid the different behavior of forerunners and monochromatic fronts, sources which are frequency-band limited can be considered or a short-time Fourier transform of the field at the observation point can be taken. Both discussions suggest that the traversal time can be determined only up to a factor of 𝒪(1).

Annalen der Physik•Dec 1, 1998•21 citations

OPTICAL PUMPING AND INTERACTION OF ATOMS WITH THE ELECTROMAGNETIC FIELD.

Claude N. Cohen-Tannoudji

•Oct 31, 1968•9 citations

Pulse propagation in an atomic medium under spontaneously generated coherence, incoherent pumping, and relative laser phase

Dong Hoang Minh, Doai Le Van, Bang Nguyen Huy

Optics Communications•Jun 22, 2018•36 citations

Front propagation in evanescent media

Μ. Büttiker, H. Thomas

Abstract We investigate the time evolution of waves in evanescent media generated by a source within this medium and observed at some distance away from the location of the source. The aim is to find a velocity which describes a causal process and is thus, for a medium with relativistic dispersion, limited by the velocity of light. For a source with a sharp onset in time, the wave function consists of a forerunner generated by the onset of the source, and of a monochromatic front. The forerunner is dominated by a frequency which decreases with time, and the monochromatic front carries the oscillation frequency of the source into the evanescent medium. For a medium with Schrödinger‐like dispersion the velocity of the front is infinite and the monochromatic front propagates with a velocity which is in agreement with the traversal time for tunneling. In the relativistic case the forerunners travel with the velocity of light and the velocity the monochromatic front is smaller than the velocity of light and only for special energies equal to the velocity of light. For sources with a sharp onset, the forerunners are not attenuated and in magnitude far exceed the monochromatic front. This renders the detection of the monochromatic front difficult. To avoid the different behavior of forerunners and monochromatic fronts, sources which are frequency‐band limited can be considered or a short‐time Fourier transform of the field at the observation point can be taken. Both discussions suggest that the traversal time can be determined only up to a factor of 𝒪(1).

Annalen der Physik•Dec 1, 1998•1 citation

PROPAGATION OF A LIGHT PULSE IN A MOVING TWO-LEVEL ABSORBING MEDIUM

Boris L Borovich, V. S. Zuev, V A Katulin +3 more

A solution is obtained for the equations describing the passage of a monochromatic radiation pulse of arbitrary shape I0(t) across a two-level absorbing medium with an activeparticle density N0 = const. It is shown that, depending on the ratio of the velocity of the medium v(t) to v0 = 2I0/N0, two modes of propagation of bleaching waves can be observed and the boundary between these modes is v = v0. The treatment is applicable to a radiation source moving at an arbitrary velocity in an absorbing medium.

Soviet Journal of Quantum Electronics•Feb 28, 1972•10 citations

Characteristics of the optical pumping of atoms in the Stark and Zeeman effects

А. Ч. Измайлов

Optics and Spectroscopy•Oct 1, 1985•0 citations
We have discovered a novel, spatially propagating wave front which is generated by laser pumping of an optically thick medium to a state of complete transparency. The wave front consists of a moving band of fluorescent light which marks the location of atoms which are being pumped. The wave-front velocity vvv, the photon flux I0{I}_{0}I0​, the atomic number density NNN, and the number nnn of photons absorbed per atom are related by v=I0\ifmmode×\else\texttimes\fi(Nn)\ensuremath−1v={I}_{0}\ifmmode\times\else\texttimes\fi{}{(\mathrm{Nn})}^{\ensuremath{-}1}v=I0​\ifmmode×\else\texttimes\fi(Nn)\ensuremath−1.
We investigate the time evolution of waves in evanescent media generated by a source within this medium and observed at some distance away from the location of the source. The aim is to find a velocity which describes a causal process and is thus, for a medium with relativistic dispersion, limited by the velocity of light. For a source with a sharp onset in time, the wave function consists of a forerunner generated by the onset of the source, and of a monochromatic front. The forerunner is dominated by a frequency which decreases with time, and the monochromatic front carries the oscillation frequency of the source into the evanescent medium. For a medium with Schrödinger-like dispersion the velocity of the front is infinite and the monochromatic front propagates with a velocity which is in agreement with the traversal time for tunneling. In the relativistic case the forerunners travel with the velocity of light and the velocity the monochromatic front is smaller than the velocity of light and only for special energies equal to the velocity of light. For sources with a sharp onset, the forerunners are not attenuated and in magnitude far exceed the monochromatic front. This renders the detection of the monochromatic front difficult. To avoid the different behavior of forerunners and monochromatic fronts, sources which are frequency-band limited can be considered or a short-time Fourier transform of the field at the observation point can be taken. Both discussions suggest that the traversal time can be determined only up to a factor of 𝒪(1).
Abstract We investigate the time evolution of waves in evanescent media generated by a source within this medium and observed at some distance away from the location of the source. The aim is to find a velocity which describes a causal process and is thus, for a medium with relativistic dispersion, limited by the velocity of light. For a source with a sharp onset in time, the wave function consists of a forerunner generated by the onset of the source, and of a monochromatic front. The forerunner is dominated by a frequency which decreases with time, and the monochromatic front carries the oscillation frequency of the source into the evanescent medium. For a medium with Schrödinger‐like dispersion the velocity of the front is infinite and the monochromatic front propagates with a velocity which is in agreement with the traversal time for tunneling. In the relativistic case the forerunners travel with the velocity of light and the velocity the monochromatic front is smaller than the velocity of light and only for special energies equal to the velocity of light. For sources with a sharp onset, the forerunners are not attenuated and in magnitude far exceed the monochromatic front. This renders the detection of the monochromatic front difficult. To avoid the different behavior of forerunners and monochromatic fronts, sources which are frequency‐band limited can be considered or a short‐time Fourier transform of the field at the observation point can be taken. Both discussions suggest that the traversal time can be determined only up to a factor of 𝒪(1).
A solution is obtained for the equations describing the passage of a monochromatic radiation pulse of arbitrary shape I0(t) across a two-level absorbing medium with an activeparticle density N0 = const. It is shown that, depending on the ratio of the velocity of the medium v(t) to v0 = 2I0/N0, two modes of propagation of bleaching waves can be observed and the boundary between these modes is v = v0. The treatment is applicable to a radiation source moving at an arbitrary velocity in an absorbing medium.