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

Refractive Index Saturation Effects in Saturated Absorption Experiments

Bernard Couillaud, A. Ducasse

Published Nov 10, 1975• 24 citations
Publisher

Abstract

Saturation effects, occurring when a laser beam tuned close to a resonance propagates through an absorbing gaseous medium, were observed by means of a second beam sent in a nearly opposite direction. In addition to the well-known signal of saturated absorption, a signal directly related to the variation of the refractive index of the medium was observed. An experiment was performed to obtain simultaneously the signals of saturated absorption and saturated dispersion of iodine vapor.

DOI
10.1103/physrevlett.35.1276

Related papers

Increase in the amplitude of a saturated absorption resonance in an active interferometer

D.Yu. Primakov, P.V. Pokasov, Sergei N Bagaev

The behaviour of the amplitude of a saturated absorption resonance observed in laser radiation propagated through an active interferometer with nonlinear amplifying and absorbing media is studied experimentally for the first time. Upon variation of the gain in the amplifying medium and preserving a constant saturating field in the interferometer, a nonlinear increase in the amplitude of the saturated absorption resonance was observed. In this case, an increase in the detected signal exceeded an increase in the noise, i.e., the signal-to-noise ratio also increased.

Quantum Electronics•Feb 28, 2005•0 citations

Shifts of the emission frequency of a third-harmonic-stabilized laser due to saturation of the refractive index

Yurii M Malyshev, Yu G Rastorguev, Alexandre N. Titov

A laser with an internal absorption cell stabilized with the aid of its third harmonic is investigated. Considerable frequency shifts are observed when the gas pressure in the cell, depth of modulation, and intensity of the saturating field are altered. These shifts are attributed to the appearance of lens-like properties in the absorbing medium under the action of a resonant field with a Gaussian intensity distribution.

Soviet Journal of Quantum Electronics•Jun 30, 1984•5 citations

Numerical simulation of nonlinear resonance spectra in aperture-limited light beams having various profiles

Vladimir Leonardovich Derbov, Sergey K. Potapov, Inna L. Plastun +3 more

Only for optically thin layers and plane waves may the intensity of a light wave be unambiguously expressed in terms of the nonlinear susceptibility of the medium. In aperture limited light beams the saturation parameter and the Stark shifts are local variables, while the output intensity of the pump and probe beams is an integral characteristic of the transmission process. The output spectrum is affected by diffraction, nonlinear refraction, and saturated absorption. The nonlinear refraction is a cause of a spectral line asymmetry which is well- known in saturation spectroscopy. In addition to usual line broadening, the saturated absorption causes specific beam effects, related to the formation of a self-induced transparency channel. The diffraction of the beam due to this self-induced aperture may result in the enhancement of the on-axis intensity, which is not a result of the self-induced lens effects. All these factors are taken into account by the mathematical model suggested in the present work. The propagation of the near-resonance saturating pump and non-saturating probe beams of various initial profiles through a homogeneously broadened two-level gas is simulated numerically. The calculations carried out make it possible to analyze the contribution of the propagation phenomena, mentioned above, to the output spectra of the beams.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Jul 1, 1992•0 citations

Wave-mixing and Phase Conjugation in Laser Active Media

Kazuo Kuroda

Nonlinear optics normally involves the change in the susceptibility of a material due to the presence of optical radiation. In many cases, the light-matter interaction produces a change in the refractive index of the medium, as occurs in photorefractive media, as well as in Kerr-like media, Brillouin-active media and absorbing media with thermallyinduced refractive index changes. Such nonlinear refractive index variation corresponds to a change in the real part of the optical susceptibility %. In resonant materials, the optical radiation induces stimulated emission (or absorption) causing transfer of population between different energy states of the medium. This can lead to saturation of the amplification (or absorption) corresponding to changes in the imaginary part of the susceptibility x= i2odk where the amplitude gain coefficient a(I) is a saturable function of the intensity /, and k is the magnitude of the wavevector of the optical radiation. The interference of two (or more) coherent beams I(x) in the laser amplifier can cause a modulation of the population inversion N(x). This modulation of the inversion is commonly known as spatial hole burning in lasers and leads to formation of a gain-grating a(x) = 1/2GN(X) where G is the stimulated emission cross-section. The gain grating can act as a very efficient diffractive optical element exhibiting high diffraction efficiency that may be even greater than unity [16] and also very high phase conjugate reflectivity using four-wave mixing (FWM) geometries [5-7].

CRC Press eBooks•Mar 14, 2002•0 citations

Non-Stationary Saturated Absorption and Refraction Effects in Laser Beams with Periodical Modulation of Frequency

Vladimir Leonardovich Derbov, Inna L. Plastun, Vladislav Viktorovich Serov +1 more

Periodical modulation of frequency, typical for spectroscopic purposes, is numerically modelled in transversely limited, propagating through a saturable two-level absorber. At modulation periods comparable with the atomic relaxation times the time and frequency dependence of the output intensity exhibits the manifestations of delayed medium response, including time-dependent lens and aperture effects that may be of importance in spectroscopy

International Conference on Laser and Fiber-Optical Networks Modeling•Jun 1, 2006•3 citations

Effects of absorption on degenerate four-wave mixing in iodine vapor

Jörg Gumbel, W. Kiefer

We have investigated degenerate four-wave mixing (DFWM) in a strongly absorbing molecular gas. A theory taking into account saturable absorption of the interacting beams is used to explain the dependence of the DFWM reflectivity on laser intensity and on the molecular number density. These parameters have a great influence on the observed spectra, owing to linear absorption that suppresses the DFWM signal in the line center of the molecular transitions. The great sensitivity of the spectra to the experimental conditions limits the applicability of DFWM for spectroscopic studies in absorbing media.

Journal of the Optical Society of America B•Dec 1, 1992•6 citations
Saturation effects, occurring when a laser beam tuned close to a resonance propagates through an absorbing gaseous medium, were observed by means of a second beam sent in a nearly opposite direction. In addition to the well-known signal of saturated absorption, a signal directly related to the variation of the refractive index of the medium was observed. An experiment was performed to obtain simultaneously the signals of saturated absorption and saturated dispersion of iodine vapor.
The behaviour of the amplitude of a saturated absorption resonance observed in laser radiation propagated through an active interferometer with nonlinear amplifying and absorbing media is studied experimentally for the first time. Upon variation of the gain in the amplifying medium and preserving a constant saturating field in the interferometer, a nonlinear increase in the amplitude of the saturated absorption resonance was observed. In this case, an increase in the detected signal exceeded an increase in the noise, i.e., the signal-to-noise ratio also increased.
Only for optically thin layers and plane waves may the intensity of a light wave be unambiguously expressed in terms of the nonlinear susceptibility of the medium. In aperture limited light beams the saturation parameter and the Stark shifts are local variables, while the output intensity of the pump and probe beams is an integral characteristic of the transmission process. The output spectrum is affected by diffraction, nonlinear refraction, and saturated absorption. The nonlinear refraction is a cause of a spectral line asymmetry which is well- known in saturation spectroscopy. In addition to usual line broadening, the saturated absorption causes specific beam effects, related to the formation of a self-induced transparency channel. The diffraction of the beam due to this self-induced aperture may result in the enhancement of the on-axis intensity, which is not a result of the self-induced lens effects. All these factors are taken into account by the mathematical model suggested in the present work. The propagation of the near-resonance saturating pump and non-saturating probe beams of various initial profiles through a homogeneously broadened two-level gas is simulated numerically. The calculations carried out make it possible to analyze the contribution of the propagation phenomena, mentioned above, to the output spectra of the beams.
Nonlinear optics normally involves the change in the susceptibility of a material due to the presence of optical radiation. In many cases, the light-matter interaction produces a change in the refractive index of the medium, as occurs in photorefractive media, as well as in Kerr-like media, Brillouin-active media and absorbing media with thermallyinduced refractive index changes. Such nonlinear refractive index variation corresponds to a change in the real part of the optical susceptibility %. In resonant materials, the optical radiation induces stimulated emission (or absorption) causing transfer of population between different energy states of the medium. This can lead to saturation of the amplification (or absorption) corresponding to changes in the imaginary part of the susceptibility x= i2odk where the amplitude gain coefficient a(I) is a saturable function of the intensity /, and k is the magnitude of the wavevector of the optical radiation. The interference of two (or more) coherent beams I(x) in the laser amplifier can cause a modulation of the population inversion N(x). This modulation of the inversion is commonly known as spatial hole burning in lasers and leads to formation of a gain-grating a(x) = 1/2GN(X) where G is the stimulated emission cross-section. The gain grating can act as a very efficient diffractive optical element exhibiting high diffraction efficiency that may be even greater than unity [16] and also very high phase conjugate reflectivity using four-wave mixing (FWM) geometries [5-7].
We have investigated degenerate four-wave mixing (DFWM) in a strongly absorbing molecular gas. A theory taking into account saturable absorption of the interacting beams is used to explain the dependence of the DFWM reflectivity on laser intensity and on the molecular number density. These parameters have a great influence on the observed spectra, owing to linear absorption that suppresses the DFWM signal in the line center of the molecular transitions. The great sensitivity of the spectra to the experimental conditions limits the applicability of DFWM for spectroscopic studies in absorbing media.