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

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE

Nonlinear wave-mixing spectroscopy for sub-Doppler isotope analysis with trace-level detection sensitivity

Wendy Lyons, Julia M. Schäfer, Ron Briggs, Marc Gregerson, William G. Tong

Published Sep 28, 2005• 0 citations
Publisher

Abstract

Nonlinear spectroscopic method based on degenerate four-wave mixing allows unusually sensitive measurement of isotopes and hyperfine profiles with sub-Doppler spectral resolution. Compared to other isotope capable methods including mass spectrometry, wave mixing offers a simple, more cost effective approach with minimal sample preparation steps. Since no two hyperfine profiles are alike, hyperfine-based isotope analysis offers unambiguous isotope information. Unlike mass-based methods such as mass spectrometry, frequency-based wave-mixing spectroscopy offers more information rich spectra. A non-planar 3-D wave-mixing optical setup generates a coherent signal beam in its own space and propagation direction. Hence, virtually 100% of the signal can be collected and detected conveniently. Using compact solid-state lasers and popular atomizers, a wave-mixing setup is relatively compact. Sub-Doppler spectral resolution can be further enhanced by using simple low-pressure atomizers. Ultrasensitive fingerprinting of important isotopes promises many potential applications.

DOI
10.1117/12.629841

Related papers

Sub-Doppler high-resolution wave-mixing detection method for isotopes in environmental applications

Ronald Briggs, Julia M. Schäfer, Wendy Lyons +1 more

Sub-Doppler laser wave-mixing spectroscopy is presented as a sensitive and high-resolution optical method for measuring isotopes and hyperfine structures. By fingerprinting isotopes at sensitive levels, one can track biohazardous pollutants in various environmental samples since isotope and hyperfine profiles are unique and characteristic of specific locations and sources including those for heavy metal contaminants and chemical runoff. We present an unusually sensitive optical absorption method that offers isotope specificity and resolution at excellent detection sensitivity levels. Sub-Doppler laser wave-mixing spectroscopy is a resonant nonlinear optical technique which uses three intersecting laser beams to produce a signal beam that has all the coherent properties of the original input laser beams. This laser-like signal beam can be efficiently directed, collected, filtered and detected. The use of counter-propagating input beams minimizes Doppler broadening and the resulting sub-Doppler spectral resolution is suitable for isotope and hyperfine splitting measurements. This relatively simple absorption-based method offers better sensitivity and selectivity levels and it requires minimum sample preparation steps.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Dec 7, 2004•4 citations

High-resolution sensitive nonlinear laser detection method for chemical analysis based on degenerate four-wave mixing

William M. Tong

Degenerate four-wave mixing (D4WM) is presented as a simple nonlinear laser method with spectral resolution high enough to resolve isotope/hyperfine lines and detection sensitivity sufficient for sub-ppb or sub-attomole detection in various atomizers and detection cells. Two counterpropagating pump beams and a probe beam are mixed inside the nonlinear medium that consists of analyte atomic or molecular species, and the phase conjugate signal beam is generated as the wavefront-reversed replica of the probe beam. Optical alignment is relatively simple, and optical signal collection is highly efficient since the signal is a laser beam. Continuous sample introduction is possible using an air-acetylene flame as the atomizer. When a relatively low-pressure demountable discharge cell is used as the atomizer, Lorentzian (pressure) broadening is also minimized in addition to cancellation of Doppler broadening. Degenerate four-wave mixing is also effective in detecting trace amounts of analytes in the condensed phase at room temperature using continuously flowing capillary cells that are suitable for interfacing to liquid chromatography and capillary electrophoresis. In addition to pulsed lasers, such as excimer- and Nd:YAG-pumped dye lasers, one can also use relatively low-power continuous-wave lasers such as argon-ion lasers or single-frequency ring dye lasers.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•May 1, 1992•1 citation

Measurement of lithium isotope ratio in various concentration samples using degenerate four-wave mixing

Xunli Yin, Xuemei Cheng, Ying Zhang +3 more

Phase-conjugate degenerate four-wave mixing (PCDFWM), as a sub-Doppler spectroscopy technique, can be employed to selectively analyze Li isotopes. It is necessary to explore the optimal incident powers in order to measure the Li isotope ratio accurately. In this case, the power condition of PCDFWM signal is first investigated using samples with various concentrations. The results indicate that the power characteristic is intimately related to the sample concentration, and the optimal incident power conditions for different sample concentrations are different. Under their own optimized power conditions, we measured the Li7/Li6 isotope ratio in Li standard solutions of 500, 300, and 200 ng/ml. The corresponding results are, respectively, 11.571±0.003, 11.552±0.003, and 11.582±0.004, which are in good agreement with the value calculated by atomic absorption spectroscopy. The information obtained from this study suggests that PCDFWM can be used to measure isotope ratios accurately in samples with different concentrations under suitable power conditions.

Applied Optics•Aug 7, 2015•4 citations

Theory of degenerate four-wave mixing in resonant Doppler-broadened media. - II. Doppler-free heterodyne spectroscopy via collinear four-wave mixing in two- and three-level systems

M. Ducloy, Daniel Bloch

In this article, we analyse a new sensitive spectroscopic technique in which a sample cell is irradiated by a two-frequency pump beam (ω + Δ ± δ/2) and a counter-propagating probe beam (ω). The phase-conjugate fields re-emitted at frequencies ω ± δ, via four-wave mixing processes, are detected through their heterodyne beating with the probe field. The properties of the heterodyne beat signal are studied by means of a perturbation calculation of the nonlinear response of the medium, carried out to the third order in the incident fields. In resonant gas media, the emission lineshape exhibits a Doppler-free doublet structure [frequency splitting 3 δ/2 for single-photon resonances, and δ/2 for two-photon transitions]. By using a phase-sensitive detection of the beat signal, one can separately analyse real (dispersion) or imaginary parts (absorption) of the nonlinear susceptibility. For single-photon transitions, the signal phase shift is related to the atomic levels lifetime and allows one to study the relaxation dynamics in gas phase (like quenching collisions, velocity diffusion, etc...). This is particularly interesting for cross-over resonances, in which only the common level contributes. In three-level systems, one also predicts a selective resonant enhancement of the phase-conjugate emission through Raman-type two-photon processes. Most of these predictions have been experimentally verified.

Journal de physique•Jan 1, 1982•48 citations

Elements hyperfine spectrum based on four-wave mixing

Zheng Tao

The new method for isotope analysis based on degenerate four wave mixing(DFWM)is proposed for superfine structure researches and the quantum optics theoretical calculation is also introduced to get the percentage of isotopes.The self-oscillation frequency can be determined from the experimental phenomenon. Then,based on three order nonlinear polarizability,with quantum optics calculation of three ladder level system,the relationship of three order nonlinear polarizability and atomic density can be measured.

Chinese Journal of Quantum Electronics•Jan 1, 2011•0 citations

Doppler-free nonlinear faraday rotatior spectroscopy of rb atoms

Rafael Drampyan, Andrew D. Greentree, Durrant, A.V

The aim of this book is to present new results in rapidly developing fields of nonlinear optics such as atomic coherence, magneto-optics of atomic media, Doppler-free spectroscopy, time-domain spectroscopy of dense atomic vapors, frequency comb spectroscopy and atom-surface interactions. The discovery of such coherent effects as coherent population trapping (CPT), electromagnetically induced transparency (EIT) and electromagnetically induced absorption (EIA) opened a new avenue for development in many fields of nonlinear optics. Investigations during the last decade have shown many related new results and approaches in nonlinear optics. These include nonlinear magneto-optical processes (NMOP) in the context of high precision magnetometry, quantum information storage and processing, magnetic resonance imaging and magnetic particle detection; the use of ultra-thin (nanometric length) atomic vapor cells in magneto-optical experiments, which show new peculiarities of both coherent effects and NMOP; the use of frequency and amplitude modulated laser beams for NMOP studies in atomic vapors with the aim of extending the range of ultra-precise magnetometers to stronger, particularly geomagnetic fields; application of the counter-propagating beam technique to reveal the Doppler free nonlinear Faraday rotation signals, as a spectroscopic tool and for applications; enhanced nonlinearity due to atomic coherence in multi-state systems; experimental study of EIT in solids; the use of the phase stabilized frequency domain combs of femtosecond laser pulses for velocity selective optical pumping of atomic hyperfine levels, as a direct frequency comb spectroscopy; time-domain nonlinear spectroscopy of dense atomic vapors; atom-surface interactions and laser induced adsorption and desorption of alkali atoms on the surface of solid materials for nanotechnology applications

•Jan 1, 2009•0 citations
Nonlinear spectroscopic method based on degenerate four-wave mixing allows unusually sensitive measurement of isotopes and hyperfine profiles with sub-Doppler spectral resolution. Compared to other isotope capable methods including mass spectrometry, wave mixing offers a simple, more cost effective approach with minimal sample preparation steps. Since no two hyperfine profiles are alike, hyperfine-based isotope analysis offers unambiguous isotope information. Unlike mass-based methods such as mass spectrometry, frequency-based wave-mixing spectroscopy offers more information rich spectra. A non-planar 3-D wave-mixing optical setup generates a coherent signal beam in its own space and propagation direction. Hence, virtually 100% of the signal can be collected and detected conveniently. Using compact solid-state lasers and popular atomizers, a wave-mixing setup is relatively compact. Sub-Doppler spectral resolution can be further enhanced by using simple low-pressure atomizers. Ultrasensitive fingerprinting of important isotopes promises many potential applications.
Sub-Doppler laser wave-mixing spectroscopy is presented as a sensitive and high-resolution optical method for measuring isotopes and hyperfine structures. By fingerprinting isotopes at sensitive levels, one can track biohazardous pollutants in various environmental samples since isotope and hyperfine profiles are unique and characteristic of specific locations and sources including those for heavy metal contaminants and chemical runoff. We present an unusually sensitive optical absorption method that offers isotope specificity and resolution at excellent detection sensitivity levels. Sub-Doppler laser wave-mixing spectroscopy is a resonant nonlinear optical technique which uses three intersecting laser beams to produce a signal beam that has all the coherent properties of the original input laser beams. This laser-like signal beam can be efficiently directed, collected, filtered and detected. The use of counter-propagating input beams minimizes Doppler broadening and the resulting sub-Doppler spectral resolution is suitable for isotope and hyperfine splitting measurements. This relatively simple absorption-based method offers better sensitivity and selectivity levels and it requires minimum sample preparation steps.
Degenerate four-wave mixing (D4WM) is presented as a simple nonlinear laser method with spectral resolution high enough to resolve isotope/hyperfine lines and detection sensitivity sufficient for sub-ppb or sub-attomole detection in various atomizers and detection cells. Two counterpropagating pump beams and a probe beam are mixed inside the nonlinear medium that consists of analyte atomic or molecular species, and the phase conjugate signal beam is generated as the wavefront-reversed replica of the probe beam. Optical alignment is relatively simple, and optical signal collection is highly efficient since the signal is a laser beam. Continuous sample introduction is possible using an air-acetylene flame as the atomizer. When a relatively low-pressure demountable discharge cell is used as the atomizer, Lorentzian (pressure) broadening is also minimized in addition to cancellation of Doppler broadening. Degenerate four-wave mixing is also effective in detecting trace amounts of analytes in the condensed phase at room temperature using continuously flowing capillary cells that are suitable for interfacing to liquid chromatography and capillary electrophoresis. In addition to pulsed lasers, such as excimer- and Nd:YAG-pumped dye lasers, one can also use relatively low-power continuous-wave lasers such as argon-ion lasers or single-frequency ring dye lasers.
Phase-conjugate degenerate four-wave mixing (PCDFWM), as a sub-Doppler spectroscopy technique, can be employed to selectively analyze Li isotopes. It is necessary to explore the optimal incident powers in order to measure the Li isotope ratio accurately. In this case, the power condition of PCDFWM signal is first investigated using samples with various concentrations. The results indicate that the power characteristic is intimately related to the sample concentration, and the optimal incident power conditions for different sample concentrations are different. Under their own optimized power conditions, we measured the Li7/Li6 isotope ratio in Li standard solutions of 500, 300, and 200 ng/ml. The corresponding results are, respectively, 11.571±0.003, 11.552±0.003, and 11.582±0.004, which are in good agreement with the value calculated by atomic absorption spectroscopy. The information obtained from this study suggests that PCDFWM can be used to measure isotope ratios accurately in samples with different concentrations under suitable power conditions.
In this article, we analyse a new sensitive spectroscopic technique in which a sample cell is irradiated by a two-frequency pump beam (ω + Δ ± δ/2) and a counter-propagating probe beam (ω). The phase-conjugate fields re-emitted at frequencies ω ± δ, via four-wave mixing processes, are detected through their heterodyne beating with the probe field. The properties of the heterodyne beat signal are studied by means of a perturbation calculation of the nonlinear response of the medium, carried out to the third order in the incident fields. In resonant gas media, the emission lineshape exhibits a Doppler-free doublet structure [frequency splitting 3 δ/2 for single-photon resonances, and δ/2 for two-photon transitions]. By using a phase-sensitive detection of the beat signal, one can separately analyse real (dispersion) or imaginary parts (absorption) of the nonlinear susceptibility. For single-photon transitions, the signal phase shift is related to the atomic levels lifetime and allows one to study the relaxation dynamics in gas phase (like quenching collisions, velocity diffusion, etc...). This is particularly interesting for cross-over resonances, in which only the common level contributes. In three-level systems, one also predicts a selective resonant enhancement of the phase-conjugate emission through Raman-type two-photon processes. Most of these predictions have been experimentally verified.
The new method for isotope analysis based on degenerate four wave mixing(DFWM)is proposed for superfine structure researches and the quantum optics theoretical calculation is also introduced to get the percentage of isotopes.The self-oscillation frequency can be determined from the experimental phenomenon. Then,based on three order nonlinear polarizability,with quantum optics calculation of three ladder level system,the relationship of three order nonlinear polarizability and atomic density can be measured.
The aim of this book is to present new results in rapidly developing fields of nonlinear optics such as atomic coherence, magneto-optics of atomic media, Doppler-free spectroscopy, time-domain spectroscopy of dense atomic vapors, frequency comb spectroscopy and atom-surface interactions. The discovery of such coherent effects as coherent population trapping (CPT), electromagnetically induced transparency (EIT) and electromagnetically induced absorption (EIA) opened a new avenue for development in many fields of nonlinear optics. Investigations during the last decade have shown many related new results and approaches in nonlinear optics. These include nonlinear magneto-optical processes (NMOP) in the context of high precision magnetometry, quantum information storage and processing, magnetic resonance imaging and magnetic particle detection; the use of ultra-thin (nanometric length) atomic vapor cells in magneto-optical experiments, which show new peculiarities of both coherent effects and NMOP; the use of frequency and amplitude modulated laser beams for NMOP studies in atomic vapors with the aim of extending the range of ultra-precise magnetometers to stronger, particularly geomagnetic fields; application of the counter-propagating beam technique to reveal the Doppler free nonlinear Faraday rotation signals, as a spectroscopic tool and for applications; enhanced nonlinearity due to atomic coherence in multi-state systems; experimental study of EIT in solids; the use of the phase stabilized frequency domain combs of femtosecond laser pulses for velocity selective optical pumping of atomic hyperfine levels, as a direct frequency comb spectroscopy; time-domain nonlinear spectroscopy of dense atomic vapors; atom-surface interactions and laser induced adsorption and desorption of alkali atoms on the surface of solid materials for nanotechnology applications