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

Optics and Spectroscopy

Transformation of spatial modulation of a light field into amplitude modulation in the interaction of a superposition of transverse modes of a He-Ne laser with iodine-127 vapors

Andrey V. Mironov

Published Jan 1, 2000• 0 citations
Publisher

Abstract

The observation of “spatial-modulation” resonances of saturated absorption in the interaction of iodine-127 vapors with a superposition of frequency-nondegenerate TEM 01 and TEM 10 transverse modes of a linear laser is reported. The modulation of the total radiation power of the probing wave, recorded at twice the beating frequency of transverse modes of the laser, is interpreted to be the result of the transformation of modulation of the spatial distribution of the field into its amplitude modulation under the action of nonlinearly absorbing iodine vapors. Resonances of saturated absorption of the weak line R (127)11-5 of iodine-127 (633 nm) in an extracavity cell are observed by the method proposed.

DOI
10.1134/1.626756

Related papers

The influence of higher spatial harmonics of atomic polarization on the saturated absorption resonance upon excitation of open dipole transitions by a field of counterpropagating waves

Denis V. Brazhnikov, A. S. Novokreshchenov

The effect of a double structure of saturated absorption resonance in the field of counterpropagating light waves interacting with an atomic gas is studied. The experimental observation of this effect was first reported in 2011 in a work by our colleagues at the P.N. Lebedev Physical Institute of the Russian Academy of Sciences (Laboratory of Frequency Standards). The essence of the effect lies in the fact that, on exciting an open dipole transition, another, narrower, resonance of an opposite sign can be observed at the center of the ordinary saturated absorption resonance. A theoretical analysis of this effect has also been performed in this work in terms of a simple spectroscopic model of an atom with two nondegenerate energy levels without taking into account higher spatial harmonics of atomic polarization and polarizations of light waves (scalar model). The present work is devoted to the development of a theory of the formation of a central narrow resonance for the example of a real F g = 1 → F e = 1 atomic transition and to the study of its main characteristics (amplitude, width, contrast, and amplitude-to-width ratio). In addition, the theoretical results obtained without taking into account the influence of higher spatial harmonics and with inclusion of the influence of first higher harmonics are compared. This comparison shows that their influence on the parameters of the new nonlinear resonance is strong even in moderately intense light fields (R ~ γ, where R is the Rabi frequency). The results of this study can be of interest for quantum metrology, as well as for many experiments in which the laser-radiation frequency is stabilized by the saturated absorption resonance on open dipole transitions in atoms and molecules.

Optics and Spectroscopy•Apr 1, 2017•1 citation

Resonance phenomena in saturation of absorption by laser radiation

Vladilen S Letokhov, V. P. Chebotaev

The review deals with resonance phenomena resulting from saturation of low-pressure-gas absorption lines by a coherent optical field, when the spectral lines are inhomogeneously broadened by the Doppler effect. Principal attention is paid to narrow resonances of width much smaller than the Doppler widths, which are produced upon saturation of the absorption by light waves under various experimental conditions (inside and outside the laser resonator, in traveling and standing waves, in spatially separated waves, etc.), owing to different effects (absorption saturation, mode interaction in the laser). Each of the phenomena is considered from both the theoretical and the experimental points of view. The phenomena considered serve as a basis of a new branch of optical spectroscopy, namely nonlinear laser spectroscopy of ultrahigh resolution.

Soviet Physics Uspekhi•Apr 30, 1975•9 citations

Phase-resolved resonance scattering and emission in iodine vapor

P. Mitra, Azriel Z. Genack

We address the distinction between resonance Raman scattering and fluorescence as the excitation source is continuously tuned through resonance. The experiments are performed in iodine vapor using a cw laser, whose intensity is electrooptically modulated in the 0.1-50-MHz frequency range. A lock-in amplifier is used to detect both the in-phase and out-of-phase response of the emission. The modulated signal is found to be the sum of two components. One component varies with angular modulation frequency ω, as (1 + ω2τ2)-1/2, where τ is the lifetime of the excited state. The other is found to be flat within the range of modulation frequency used in the experiment. Since the results of the modulation experiment are the Fourier transform of the response to pulsed excitation, the first component corresponds to exponential decay with the fluorescence lifetime and the second corresponds to a prompt response. A density matrix calculation shows that the prompt response would be absent if the absorption were independent of laser frequency. It exists as a result of the finite inhomogeneous linewidth and the laser detuning from the center of the transition. The amplitude of the delayed and prompt components is a function of laser frequency. This gives a full description of the dynamical response to the emission to linear excitation as the laser is tuned continuously through resonance. The response of the sample to nonlinear excitation is also discussed.

Annual Meeting Optical Society of America•Jan 1, 1985•0 citations

Resonance fluorescence with modulated excitation

Stephen H. Chakmakjian, Karl W. Koch, Carlos R. Stroud +1 more

We report our results on measurement of the total fluorescent power radiated by two-level atoms excited by a 100% amplitude modulated or bichromatic laser field. For the case of single-frequency excitation, it is well known that the total fluorescent power monotonically saturates as the intensity of the field is increased. This occurs because the inversion of the atoms approaches zero at high field strengths. In contrast, when the field is bichromatic the total fluorescent power displays resonant peaks as the strength of the driving field is increased. This occurs because there is enhanced absorption when the modulation frequency coincides with the Rabi freqeuncy or one of its subharmonics.

Annual Meeting Optical Society of America•Jan 1, 1987•0 citations

Propagation of modulated optical fields through saturable-absorbing media: a general theory of modulation spectroscopy

Mark A. Kramer, Robert W. Boyd, Lloyd W. Hillman +1 more

The propagation of a weakly modulated light beam through a nonlinear material is treated. The optical field representing such a beam consists of a strong carrier-frequency component and two weak, symmetrically displaced sidebands that combine to form a field, which may be purely amplitude modulated (AM), frequency modulated (FM), or some combination of these two modulation forms. It is shown that, for any optical nonlinearity, two modulation forms exist that have the property that the form of modulation is invariant under propagation of the beam. If a modulation form other than one of these natural modes is injected into the nonlinear medium, the modulation form will change as the beam propagates, asymptotically approaching the natural mode that experiences the lower attenuation. Explicit expressions for these natural modes are presented for the case in which the nonlinear medium can be modeled as a collection of two-level atoms. For the special case of an on-resonance pump beam, the natural modes correspond to pure amplitude modulation and pure frequency modulation. This formalism provides a general description of saturation spectroscopy for both AM and FM fields. Formulas are derived for the rate at which a pure FM beam is converted to an AM beam owing to its interaction with a two-level atomic medium. We also consider the variation that is due to propagation of the depth of modulation of an AM wave interacting resonantly with two-level atoms. The formalism predicts the existence of spectral features whose shape depends sensitively on the internal relaxation processes of the material. Experimental spectra are presented for ruby, alexandrite, and fluorescein in glass and are interpreted.

Journal of the Optical Society of America B•Sep 1, 1985•22 citations

Modulated emission in iodine vapor

Azriel Z. Genack, P. M. Mitra, Axel Schenzle

The response of emission in I2 vapor to intensity modulated light at radial frequency ω is measured and described in terms of the lifetime of the excited state, T1, the rate of phase interrupting collisions γ, and the inhomogeneously broadened absorption line. When the laser is tuned to resonance, the variation of amplitude of the modulated emission with ω corresponds to a single exponential decay with lifetime T1. Off resonance, the modulation is described as the sum of the above ‘‘delayed’’ component and a ‘‘prompt’’ in‐phase component which is independent of modulation frequency. The ratio of the delayed to prompt component for off resonant excitation is shown to be 2γT1. This relation is used to determine the rate of phase interrupting collisions in I2 vapor.

AIP conference proceedings•Jan 1, 1986•0 citations
The observation of “spatial-modulation” resonances of saturated absorption in the interaction of iodine-127 vapors with a superposition of frequency-nondegenerate TEM 01 and TEM 10 transverse modes of a linear laser is reported. The modulation of the total radiation power of the probing wave, recorded at twice the beating frequency of transverse modes of the laser, is interpreted to be the result of the transformation of modulation of the spatial distribution of the field into its amplitude modulation under the action of nonlinearly absorbing iodine vapors. Resonances of saturated absorption of the weak line R (127)11-5 of iodine-127 (633 nm) in an extracavity cell are observed by the method proposed.
The effect of a double structure of saturated absorption resonance in the field of counterpropagating light waves interacting with an atomic gas is studied. The experimental observation of this effect was first reported in 2011 in a work by our colleagues at the P.N. Lebedev Physical Institute of the Russian Academy of Sciences (Laboratory of Frequency Standards). The essence of the effect lies in the fact that, on exciting an open dipole transition, another, narrower, resonance of an opposite sign can be observed at the center of the ordinary saturated absorption resonance. A theoretical analysis of this effect has also been performed in this work in terms of a simple spectroscopic model of an atom with two nondegenerate energy levels without taking into account higher spatial harmonics of atomic polarization and polarizations of light waves (scalar model). The present work is devoted to the development of a theory of the formation of a central narrow resonance for the example of a real F g = 1 → F e = 1 atomic transition and to the study of its main characteristics (amplitude, width, contrast, and amplitude-to-width ratio). In addition, the theoretical results obtained without taking into account the influence of higher spatial harmonics and with inclusion of the influence of first higher harmonics are compared. This comparison shows that their influence on the parameters of the new nonlinear resonance is strong even in moderately intense light fields (R ~ γ, where R is the Rabi frequency). The results of this study can be of interest for quantum metrology, as well as for many experiments in which the laser-radiation frequency is stabilized by the saturated absorption resonance on open dipole transitions in atoms and molecules.
The review deals with resonance phenomena resulting from saturation of low-pressure-gas absorption lines by a coherent optical field, when the spectral lines are inhomogeneously broadened by the Doppler effect. Principal attention is paid to narrow resonances of width much smaller than the Doppler widths, which are produced upon saturation of the absorption by light waves under various experimental conditions (inside and outside the laser resonator, in traveling and standing waves, in spatially separated waves, etc.), owing to different effects (absorption saturation, mode interaction in the laser). Each of the phenomena is considered from both the theoretical and the experimental points of view. The phenomena considered serve as a basis of a new branch of optical spectroscopy, namely nonlinear laser spectroscopy of ultrahigh resolution.
We address the distinction between resonance Raman scattering and fluorescence as the excitation source is continuously tuned through resonance. The experiments are performed in iodine vapor using a cw laser, whose intensity is electrooptically modulated in the 0.1-50-MHz frequency range. A lock-in amplifier is used to detect both the in-phase and out-of-phase response of the emission. The modulated signal is found to be the sum of two components. One component varies with angular modulation frequency ω, as (1 + ω2τ2)-1/2, where τ is the lifetime of the excited state. The other is found to be flat within the range of modulation frequency used in the experiment. Since the results of the modulation experiment are the Fourier transform of the response to pulsed excitation, the first component corresponds to exponential decay with the fluorescence lifetime and the second corresponds to a prompt response. A density matrix calculation shows that the prompt response would be absent if the absorption were independent of laser frequency. It exists as a result of the finite inhomogeneous linewidth and the laser detuning from the center of the transition. The amplitude of the delayed and prompt components is a function of laser frequency. This gives a full description of the dynamical response to the emission to linear excitation as the laser is tuned continuously through resonance. The response of the sample to nonlinear excitation is also discussed.
We report our results on measurement of the total fluorescent power radiated by two-level atoms excited by a 100% amplitude modulated or bichromatic laser field. For the case of single-frequency excitation, it is well known that the total fluorescent power monotonically saturates as the intensity of the field is increased. This occurs because the inversion of the atoms approaches zero at high field strengths. In contrast, when the field is bichromatic the total fluorescent power displays resonant peaks as the strength of the driving field is increased. This occurs because there is enhanced absorption when the modulation frequency coincides with the Rabi freqeuncy or one of its subharmonics.
The propagation of a weakly modulated light beam through a nonlinear material is treated. The optical field representing such a beam consists of a strong carrier-frequency component and two weak, symmetrically displaced sidebands that combine to form a field, which may be purely amplitude modulated (AM), frequency modulated (FM), or some combination of these two modulation forms. It is shown that, for any optical nonlinearity, two modulation forms exist that have the property that the form of modulation is invariant under propagation of the beam. If a modulation form other than one of these natural modes is injected into the nonlinear medium, the modulation form will change as the beam propagates, asymptotically approaching the natural mode that experiences the lower attenuation. Explicit expressions for these natural modes are presented for the case in which the nonlinear medium can be modeled as a collection of two-level atoms. For the special case of an on-resonance pump beam, the natural modes correspond to pure amplitude modulation and pure frequency modulation. This formalism provides a general description of saturation spectroscopy for both AM and FM fields. Formulas are derived for the rate at which a pure FM beam is converted to an AM beam owing to its interaction with a two-level atomic medium. We also consider the variation that is due to propagation of the depth of modulation of an AM wave interacting resonantly with two-level atoms. The formalism predicts the existence of spectral features whose shape depends sensitively on the internal relaxation processes of the material. Experimental spectra are presented for ruby, alexandrite, and fluorescein in glass and are interpreted.
The response of emission in I2 vapor to intensity modulated light at radial frequency ω is measured and described in terms of the lifetime of the excited state, T1, the rate of phase interrupting collisions γ, and the inhomogeneously broadened absorption line. When the laser is tuned to resonance, the variation of amplitude of the modulated emission with ω corresponds to a single exponential decay with lifetime T1. Off resonance, the modulation is described as the sum of the above ‘‘delayed’’ component and a ‘‘prompt’’ in‐phase component which is independent of modulation frequency. The ratio of the delayed to prompt component for off resonant excitation is shown to be 2γT1. This relation is used to determine the rate of phase interrupting collisions in I2 vapor.