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 Letters

Quantitative characteristics of pressure-induced degenerate frequency resonance in four-wave mixing with continuous-wave laser beams

A. R. Bogdan, M. C. Downer, N. Bloembergen

Published Jul 1, 1981• 54 citations
Publisher

Abstract

The linewidth and intensity of the four-wave degenerate mixing signal in Na vapor have been observed as functions of He buffer-gas pressure with cw single-mode dye-laser beams. The width is independent of He pressure, and a quantitative comparison with theory is made. We also report the observation of a new effect, a four-wave mixing Raman-type resonance between two equally populated hyperfine levels.

DOI
10.1364/ol.6.000348

Related papers

Quantitative characteristics of pressure-induced four-wave mixing signals observed with cw laser beams

A. Bogdan, M. C. Downer, N. Bloembergen

We report observation of a pressure-induced extra resonance in four-wave mixing (PIER4 signal) using single-mode continuous-wave dye lasers. The narrow laser linewidth permits for the first time a quantitative verification of the frequency, intensity, and pressure dependence of the PIER4 signal predicted by the theory of the nonlinear susceptibility ${\ensuremath{\chi}}^{(3)}$.

Physical Review A•Jul 1, 1981•58 citations

Pressure-induced degenerate frequency resonance in four-wave light mixing

A. R. Bogdan, Yehiam Prior, N. Bloembergen

Phase-matched four-wave mixing in sodium vapor with a helium buffer gas is carried out in a noncoplanar geometry. The directions of the four light beams remain nondegenerate even if all frequencies are equal. A sharp zerodifference frequency resonance in the intensity of the parametrically generated fourth beam by three incident beams is observed that is proportional to the square of the pressure of the buffer gas. A theoretical interpretation of this effect caused by elimination of destructive interference between two coherent pathways is presented.

Optics Letters•Feb 1, 1981•80 citations

Resonant degenerate four-wave mixing in I_2: effect of buffer gas pressure

P. F. Barker, Amberyn M. Thomas, Halina H. Rubinsztein-Dunlop +2 more

The influence of molecular collisions on the production of the degenerate four-wave mixing signal in I(2) is presented. Measurements were performed on gaseous molecular iodine, I(2), contained in a glass cell in which pressure, temperature, and species concentration are easily and independently varied. Frequencydoubled outputs from a seeded Nd:YAG laser and an excimer-pumped dye laser were used as excitation sources. We have studied the dependence of signal strength versus buffer gas pressure, with pump intensity as a third parameter. It is evident from our results that, for pump intensities of less than 1 MW/cm(2), the pressure dependence of the signal follows that given by a simple two-level model in the homogeneously broadened regime. In this regime collisional deexcitation becomes significant, leading to changes in saturation intensity. This is evidenced by a reduction in the signal with an increase in buffer gas pressure. This behavior is similar to that seen in laser-induced fluorescence. At higher pump intensities, the signal is seen to increase with pressure; this behavior cannot be described by the simple two-level model.

Applied Optics•Jun 20, 1995•3 citations

Measurement of cw HF laser resonant degenerate four-wave mixing in an absorbing HF gas

John G. Coffer, R. A. Chodzko, Jay M. Bernard +1 more

Continuous wave (cw) phase conjugation of a HF laser beam has been observed using resonant degenerate four-wave mixing in a HF gas absorption cell. A HF laser was operated in the P1(8) transition to provide total (forward plus backward) pump beam and probe beam intensities of about 400 and 30 W/cm2, respectively, in the cell. Conjugate reflectivities were measured as a function of HF pressure and frequency detuning from line center. Reflectivities of the order of 10−4 were measured at HF gas pressures of the order of 2 Torr when the laser frequency was tuned near line center.

Applied Physics Letters•Apr 16, 1990•3 citations

High-resolution four-wave light-mixing studies of collision-induced coherence in Na vapor

Lewis J. Rothberg, N. Bloembergen

Near-resonant four-wave light mixing in Na vapor with inert buffer gases reveals collision-induced coherences when the difference frequency between two incident light beams equals the hyperfine splitting or the Zeeman splitting between two states of the $3^{2}S$ ground-state manifold. The Doppler broadening of the corresponding resonances decreases with increasing buffer-gas pressure. The width of the resonances becomes significantly narrower than the spontaneous linewidth of the near-resonant intermediate state and is determined by spin-exchange collisions between ground-state atoms. The dependence of the intensity of these collision-induced resonances on buffer-gas pressure and detuning from one-photon resonances is measured. Selection rules for various polarizations of the incident light fields and directions of an externally applied magnetic field are established.

Physical Review A•Aug 1, 1984•90 citations

Nonimpact degenerate four-wave mixing in Na perturbed by He

Nissim Asida, M. Rosenbluh, Shaul Mukamel

Collisionally induced four-wave mixing (FWM) signals have been observed in Na vapor broadened by He buffer gas at large detunings from resonance. Analytical expressions are developed which do not use the collisional impact approximation and which accurately describe the dependence of the FWM intensity on laser detuning and incident laser intensity. The measurements and the theory are used to calculate the nonimpact collisional lineshape for the Na-He system for detunings of 40 to 200 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ from the D line resonances.

Physical Review A•Oct 1, 1989•2 citations
The linewidth and intensity of the four-wave degenerate mixing signal in Na vapor have been observed as functions of He buffer-gas pressure with cw single-mode dye-laser beams. The width is independent of He pressure, and a quantitative comparison with theory is made. We also report the observation of a new effect, a four-wave mixing Raman-type resonance between two equally populated hyperfine levels.
Phase-matched four-wave mixing in sodium vapor with a helium buffer gas is carried out in a noncoplanar geometry. The directions of the four light beams remain nondegenerate even if all frequencies are equal. A sharp zerodifference frequency resonance in the intensity of the parametrically generated fourth beam by three incident beams is observed that is proportional to the square of the pressure of the buffer gas. A theoretical interpretation of this effect caused by elimination of destructive interference between two coherent pathways is presented.
The influence of molecular collisions on the production of the degenerate four-wave mixing signal in I(2) is presented. Measurements were performed on gaseous molecular iodine, I(2), contained in a glass cell in which pressure, temperature, and species concentration are easily and independently varied. Frequencydoubled outputs from a seeded Nd:YAG laser and an excimer-pumped dye laser were used as excitation sources. We have studied the dependence of signal strength versus buffer gas pressure, with pump intensity as a third parameter. It is evident from our results that, for pump intensities of less than 1 MW/cm(2), the pressure dependence of the signal follows that given by a simple two-level model in the homogeneously broadened regime. In this regime collisional deexcitation becomes significant, leading to changes in saturation intensity. This is evidenced by a reduction in the signal with an increase in buffer gas pressure. This behavior is similar to that seen in laser-induced fluorescence. At higher pump intensities, the signal is seen to increase with pressure; this behavior cannot be described by the simple two-level model.
Continuous wave (cw) phase conjugation of a HF laser beam has been observed using resonant degenerate four-wave mixing in a HF gas absorption cell. A HF laser was operated in the P1(8) transition to provide total (forward plus backward) pump beam and probe beam intensities of about 400 and 30 W/cm2, respectively, in the cell. Conjugate reflectivities were measured as a function of HF pressure and frequency detuning from line center. Reflectivities of the order of 10−4 were measured at HF gas pressures of the order of 2 Torr when the laser frequency was tuned near line center.
Near-resonant four-wave light mixing in Na vapor with inert buffer gases reveals collision-induced coherences when the difference frequency between two incident light beams equals the hyperfine splitting or the Zeeman splitting between two states of the 32S3^{2}S32S ground-state manifold. The Doppler broadening of the corresponding resonances decreases with increasing buffer-gas pressure. The width of the resonances becomes significantly narrower than the spontaneous linewidth of the near-resonant intermediate state and is determined by spin-exchange collisions between ground-state atoms. The dependence of the intensity of these collision-induced resonances on buffer-gas pressure and detuning from one-photon resonances is measured. Selection rules for various polarizations of the incident light fields and directions of an externally applied magnetic field are established.
Collisionally induced four-wave mixing (FWM) signals have been observed in Na vapor broadened by He buffer gas at large detunings from resonance. Analytical expressions are developed which do not use the collisional impact approximation and which accurately describe the dependence of the FWM intensity on laser detuning and incident laser intensity. The measurements and the theory are used to calculate the nonimpact collisional lineshape for the Na-He system for detunings of 40 to 200 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ from the D line resonances.