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

IEEE Journal of Quantum Electronics

Saturation and tuning behavior of stimulated electronic Raman scattering

D. Cotter, D. Hanna

Published Mar 1, 1978• 27 citations
Publisher

Abstract

The saturation behavior of stimulated electronic Raman scattering (SERS) in atomic vapors is studied theoretically and experimentally. Limits to the SERS output energy are imposed by both pump depletion and saturation of the Raman transition. The effects of these on the performance of tunable infrared lasers based on SERS are examined.
DOI
10.1109/jqe.1978.1069759

Related papers

Some investigations into stimulated electronic Raman scattering and related processes in atomic vapours

David Brian Hearn

Stimulated electronic Raman scattering, SERS, is a simple method of efficiently generating widely tunable infrared radiation. This work describes techniques by which the tuning capability of this process may be extended. To this end several schemes in Caesium and Barium vapours have been investigated. In Barium vapour two Raman transitions were studied using fixed frequency lasers. Poor performance of one of these transitions led to the application of biharmonic pumping or 'coherent Raman mixing' to enable generation of infrared light, and was the first observation of this process in an atomic vapour. This technique was subsequently used to generate infrared light from tunable dye laser light, which gave continuous tuning from 1.16µm to 1.5µm. The process was found to be limited by atomic saturation. The effect which saturation has on the generation efficiency is considered theoretically, and predicts quite accurately the observed tuning behaviour. Two methods aimed at reducing molecular absorption effects in SERS in alkali vapours were investigated. The techniques employed either laser excitation and dissociation of the molecules or a reduction in their ground state concentration by superheating of the vapour. Some degree of success was achieved in improving the available tuning from the 6s-7s transition in Caesium. However, the inclusion of the effect of collision broadening of atomic transitions into a calculation of the Raman threshold suggests that little further improvement can be obtained on this transition. A direct measurement of the Raman threshold power on the 6s-5d5/2 transition in Caesium gave excellent agreement with theoretical predictions based on collision broadening of this Raman transition. In addition, this work gave an insight into the role photoionization plays in increasing the threshold under certain circumstances. The analysis suggests that laser pulse duration and vapour column length are important in determining whether Raman threshold can be exceeded.

•Jan 1, 1982•0 citations

Stimulated electronic Raman scatterng in sodium vapor

Xiaofeng Han, Zhenguo Lu, Zuguang Ma +1 more

The observation of a stimulated electronic Raman scattering (SERS) on 3s–4s transition in sodium vapor pumped by a PTP dye laser is reported. Infrared output (Stokes) tunable from 2.38 μm to 2.65 μm has been obtained as the dye laser is tuned from 334.0 nm to 338.8 nm. Maximum photon conversion efficiency is about 30%.

AIP conference proceedings•Jan 1, 1987•0 citations

Stimulated Raman processes in metal vapours

W.H.W. Tuttlebee

Recent work has demonstrated the potential of stimulated electronic Raman scattering, SERS, as a tunable IR source. The current work has aimed at an extension of the performance of SERS in the two areas of tuning capability and narrower linewidth; to this end a variety of stimulated electronic Raman schemes have been investigated. Initially the theoretical background of SERS and of various possible competing processes is reviewed. The construction and performance of the dye lasers and heat pipe ovens used for the work are then described, followed by a presentation and discussion of the experimental work performed; this work falls into four main areas. Firstly the potential of pump and SERS feedback schemes to extend the tuning ranges of an existing alkali metal SERS system, Cs 6s-7s, has been investigated, under non-optimum conditions; results from this appear promising for future work. Secondly, we have demonstrated for the first time the possibility of obtaining a tunable IR output from a fifth order nonlinear process, stimulated hyper-Raman scattering, SHRS, in Na vapour. Various aspects of theory and behaviour of this process are described. The advantages of obtaining SERS from an excited initial state have been considered; preliminary results have proved disappointing and have led us to consider possible limiting mechanisms in such processes. Finally SERS in alkaline earths is considered; only few such schemes would appear to be viable for various reasons. One such scheme in Ba has however yielded a 0.2cm-1 system-limited SERS linewidth, a narrower SERS linewidth than has previously been attained; indications are that narrower linewidths still may be attainable, although further work will be necessary to verify this. These results also suggest that the optical Stark effect and power broadening have less influence on the Raman linewidth than has previously been thought.

•Dec 1, 1977•0 citations

Effect of the pump absorption on generation of infrared stimulated electronic Raman scattering in alkali-metal vapors

A. I. Agafonov, G. G. Grigoryan, Nikolay V Znamenskiy +5 more

The main properties of infrared stimulated electronic Raman scattering (SERS) at the 6 2 S 1/2 -7 2 S 1/2, 3/2 transitions in cesium atoms are studied theoretically and experimentally as functions of the atomic concentration, which was varied from 10 11 to 10 16 cm −3 . It is found that the efficiency of generation of Stokes radiation strongly depends on one-photon absorption of the pump radiation tuned near frequencies of the 6 2 S 1/2 -7 2 P 1/2, 3/2 transitions. By using the equation for the density matrix, which describes the evolution of a three-level system, the theory of resonance excitation of IR radiation upon one-photon absorption at an adjacent transition is developed. The theory describes well the main features of IR SERS in alkali-metal vapors.

Journal of Experimental and Theoretical Physics•Apr 1, 2002•0 citations

Effects of ground-state depletion of atoms in stimulated Raman scattering of metal vapors

Yunsheng Huo, Qihong Lou, Zian Ding +1 more

The effects of ground state depletion of atoms on the characteristics of stimulated Raman scattering in metal vapors are studied by simultaniously solving the rate-equation of the atom energy levels related in the Raman scattering, and the equations describing the energy-conversion from the focused pump laser pulses to the Raman down-converted pulses. The ground state of metal atoms are depleted most strongly in the regions near the focal spots of the pump beams because of the higher intensities of light and smaller available medium volume in thosa regions. This will result in the unsymmetrical shapes of the Raman-shifted pulses for the front and rear edges, and will reduce the energy-conversion efficiency.

Acta Optica Sinica•Jan 1, 1987•0 citations

Effects of ground-state depletion of atoms in stimulated Raman scattering of metal vapors

Yunsheng Huo, Qihong Lou, Zian Ding +1 more

The effects of ground-state depletion of atoms on the characteristics of stimulated Raman scattering in metal vapors are studied by simultaneously solving the rate equation of the atomic energy levels related in the Raman scattering, and the equations describing the energy conversion from the focused pump-laser pulses to the Raman down-converted pulses. The ground states of metal atoms are depleted most strongly in the regions near the focal spots of the pump beams because of the higher intensities of light and smaller available medium volume in those regions. This will result in the unsymmetrical shapes of the Raman-shifted pulses for the front and rear edges, and will reduce the energy-conversion efficiency.

Acta Physica Sinica•Jan 1, 1989•0 citations
Stimulated electronic Raman scattering, SERS, is a simple method of efficiently generating widely tunable infrared radiation. This work describes techniques by which the tuning capability of this process may be extended. To this end several schemes in Caesium and Barium vapours have been investigated. In Barium vapour two Raman transitions were studied using fixed frequency lasers. Poor performance of one of these transitions led to the application of biharmonic pumping or 'coherent Raman mixing' to enable generation of infrared light, and was the first observation of this process in an atomic vapour. This technique was subsequently used to generate infrared light from tunable dye laser light, which gave continuous tuning from 1.16µm to 1.5µm. The process was found to be limited by atomic saturation. The effect which saturation has on the generation efficiency is considered theoretically, and predicts quite accurately the observed tuning behaviour. Two methods aimed at reducing molecular absorption effects in SERS in alkali vapours were investigated. The techniques employed either laser excitation and dissociation of the molecules or a reduction in their ground state concentration by superheating of the vapour. Some degree of success was achieved in improving the available tuning from the 6s-7s transition in Caesium. However, the inclusion of the effect of collision broadening of atomic transitions into a calculation of the Raman threshold suggests that little further improvement can be obtained on this transition. A direct measurement of the Raman threshold power on the 6s-5d5/2 transition in Caesium gave excellent agreement with theoretical predictions based on collision broadening of this Raman transition. In addition, this work gave an insight into the role photoionization plays in increasing the threshold under certain circumstances. The analysis suggests that laser pulse duration and vapour column length are important in determining whether Raman threshold can be exceeded.
Recent work has demonstrated the potential of stimulated electronic Raman scattering, SERS, as a tunable IR source. The current work has aimed at an extension of the performance of SERS in the two areas of tuning capability and narrower linewidth; to this end a variety of stimulated electronic Raman schemes have been investigated. Initially the theoretical background of SERS and of various possible competing processes is reviewed. The construction and performance of the dye lasers and heat pipe ovens used for the work are then described, followed by a presentation and discussion of the experimental work performed; this work falls into four main areas. Firstly the potential of pump and SERS feedback schemes to extend the tuning ranges of an existing alkali metal SERS system, Cs 6s-7s, has been investigated, under non-optimum conditions; results from this appear promising for future work. Secondly, we have demonstrated for the first time the possibility of obtaining a tunable IR output from a fifth order nonlinear process, stimulated hyper-Raman scattering, SHRS, in Na vapour. Various aspects of theory and behaviour of this process are described. The advantages of obtaining SERS from an excited initial state have been considered; preliminary results have proved disappointing and have led us to consider possible limiting mechanisms in such processes. Finally SERS in alkaline earths is considered; only few such schemes would appear to be viable for various reasons. One such scheme in Ba has however yielded a 0.2cm-1 system-limited SERS linewidth, a narrower SERS linewidth than has previously been attained; indications are that narrower linewidths still may be attainable, although further work will be necessary to verify this. These results also suggest that the optical Stark effect and power broadening have less influence on the Raman linewidth than has previously been thought.
The main properties of infrared stimulated electronic Raman scattering (SERS) at the 6 2 S 1/2 -7 2 S 1/2, 3/2 transitions in cesium atoms are studied theoretically and experimentally as functions of the atomic concentration, which was varied from 10 11 to 10 16 cm −3 . It is found that the efficiency of generation of Stokes radiation strongly depends on one-photon absorption of the pump radiation tuned near frequencies of the 6 2 S 1/2 -7 2 P 1/2, 3/2 transitions. By using the equation for the density matrix, which describes the evolution of a three-level system, the theory of resonance excitation of IR radiation upon one-photon absorption at an adjacent transition is developed. The theory describes well the main features of IR SERS in alkali-metal vapors.
The effects of ground state depletion of atoms on the characteristics of stimulated Raman scattering in metal vapors are studied by simultaniously solving the rate-equation of the atom energy levels related in the Raman scattering, and the equations describing the energy-conversion from the focused pump laser pulses to the Raman down-converted pulses. The ground state of metal atoms are depleted most strongly in the regions near the focal spots of the pump beams because of the higher intensities of light and smaller available medium volume in thosa regions. This will result in the unsymmetrical shapes of the Raman-shifted pulses for the front and rear edges, and will reduce the energy-conversion efficiency.
The effects of ground-state depletion of atoms on the characteristics of stimulated Raman scattering in metal vapors are studied by simultaneously solving the rate equation of the atomic energy levels related in the Raman scattering, and the equations describing the energy conversion from the focused pump-laser pulses to the Raman down-converted pulses. The ground states of metal atoms are depleted most strongly in the regions near the focal spots of the pump beams because of the higher intensities of light and smaller available medium volume in those regions. This will result in the unsymmetrical shapes of the Raman-shifted pulses for the front and rear edges, and will reduce the energy-conversion efficiency.