IEEE Journal of Quantum Electronics

The influence of a second resonance on the saturation characteristics of the four-wave sum mixing

E. Koudoumas, Thomas Efthimiopoulos

Published Jan 1, 1995• 5 citations

Abstract

Experimental results are presented, related to the saturation mechanisms of the four-wave sum mixing (4-WSM) generation in Hg when a double resonance enhancement is employed, that is, a two photon resonance to the /spl delta//sup 1/S/sub 0/ state followed by the /spl delta//sup 1/S/sub 0/-6p'/sup 3/D/sub 1/ one photon coupling. This coupling is shown to alter the saturation characteristics of the four-wave sum mixing radiation by affecting the two-photon excitation to the /spl delta//sup 1/S/sub 0/ state, reduce the ionization of the Hg atoms by the incoming radiation and create an absorption window for the generated radiation in a region near the autoionizing state by modifying the linear susceptibility.>

DOI: 10.1109/3.348068

Related papers

Double resonant four-wave sum mixing near an autoionizing state

E. Koudoumas, Tom Efthimiopoulos

It is shown that in the double resonant four-wave sum mixing, the coupling between excited states alters the saturation, the two-photon transition rate, the ionization, the absorption of the generated radiation, and the phase matching in the region near an autoionizing state.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIEMay 4, 19930 citations

Effects of four-wave mixing on four-photon resonance excitation and ionization in the presence of a three-photon intermediate state resonance enhancement

M. G. Payne, J. C. Miller, Roger C. Hart +1 more

Physical Review ADec 1, 199119 citations

Suppression of a four-photon resonance by four-wave mixing near an intermediate three-photon resonance

Roger C. Hart, W. R. Garrett, M. G. Payne

Physical Review AOct 1, 199212 citations

Level splitting effects in CW resonant four-wave mixing

Sergei A Babin, S.I. Kalukov, U. Hinze +2 more

Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)Nov 11, 20020 citations

Role of atomic coherence effects in four-wave mixing using autoionizing resonances

M. Anscombe, Rebeca de Nalda, İbrahim Küçükkara +1 more

Physical Review AOct 8, 20032 citations

Enhanced production of coherent vuv radiation by four-wave mixing in Sr vapor

Gary C. Bjorklund, John E. Bjorkholm, Richard R. Freeman +1 more

Significant enhancement of the unsaturated conversion efficiencies of four-wave sum frequency mixing processes involving autoionizing states in Sr vapor is obtained by utilizing the 5s7s 1S0 two-photon channel and phase matching by frequency adjustment. Extrapolation to low power levels indicates that production of cw vuv radiation may be possible. A saturation effect arising from depletion of one of the fundamental beams by two-photon absorption is observed.

Applied Physics LettersSep 1, 197732 citations

IEEE Journal of Quantum Electronics

The influence of a second resonance on the saturation characteristics of the four-wave sum mixing

E. Koudoumas, Thomas Efthimiopoulos

Published Jan 1, 1995• 5 citations

Publisher

Abstract

DOI: 10.1109/3.348068

Related papers

Double resonant four-wave sum mixing near an autoionizing state

E. Koudoumas, Tom Efthimiopoulos

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIEMay 4, 19930 citations

Effects of four-wave mixing on four-photon resonance excitation and ionization in the presence of a three-photon intermediate state resonance enhancement

M. G. Payne, J. C. Miller, Roger C. Hart +1 more

We consider effects which occur when four-wave sum frequency generation and multiphoton ionization are induced by lasers tuned near a three-photon resonance and simultaneously near or at a dipole allowed four-photon resonance. In studies with unfocused laser beams, if the phase mismatch of the generated four-wave-mixing field is large and the related two-photon resonance for the absorption of a four-wave-mixing photon and a laser photon results in strong absorption of the four-wave-mixing field, a coherent cancellation occurs between the pumping of the resonance by two- and four-photon processes. This interference effect occurs when the first laser is tuned on either side of the three-photon resonance and \ensuremath{\Vert}\ensuremath{\Delta} ${\mathit{k}}_{\mathit{r}}$ L\ensuremath{\Vert}\ensuremath{\gg}1, where \ensuremath{\Delta} ${\mathit{k}}_{\mathit{r}}$ is the mismatch and L is the length of the path of the laser beams in the gas. With focused laser beams large differences occur between ionization with unidirectional beams and with counterpropagating laser beams when \ensuremath{\Vert}\ensuremath{\Delta} ${\mathit{k}}_{\mathit{r}}$ b\ensuremath{\Vert}\ensuremath{\gg}1, where b is the confocal parameter of the focused laser beams. Strong absorption of the four-wave-mixing field is shown not to be necessary for strong destructive interference with focused laser beams when the phase mismatch is large. This work also suggests an explanation for earlier experiments where the presence of a four-photon resonance enabled the generation of third-harmonic light in a positively dispersive wavelength region. We argue that this process can occur when the laser used to achieve the four-photon resonance is focused on the small z (z is the coordinate in the direction of propagation) side of the focal point of the laser responsible for the third-harmonic generation. In this way the absorption of the third-harmonic light on one side of the focal point is made much stronger than on the other side. Correspondingly, contributions to the third-harmonic field from the two sides of the focal point are unequal and cannot undergo complete destructive interference as would otherwise occur in a positively dispersive region.We consider effects which occur when four-wave sum frequency generation and multiphoton ionization are induced by lasers tuned near a three-photon resonance and simultaneously near or at a dipole allowed four-photon resonance. In studies with unfocused laser beams, if the phase mismatch of the generated four-wave-mixing field is large and the related two-photon resonance for the absorption of a four-wave-mixing photon and a laser photon results in strong absorption of the four-wave-mixing field, a coherent cancellation occurs between the pumping of the resonance by two- and four-photon processes. This interference effect occurs when the first laser is tuned on either side of the three-photon resonance and \ensuremath{\Vert}\ensuremath{\Delta}${\mathit{k}}_{\mathit{r}}$L\ensuremath{\Vert}\ensuremath{\gg}1, where \ensuremath{\Delta}${\mathit{k}}_{\mathit{r}}$ is the mismatch and L is the length of the path of the laser beams in the gas. With focused laser beams large differences occur between ionization with unidirectional beams and with counterpropagating laser beams when \ensuremath{\Vert}\ensuremath{\Delta}${\mathit{k}}_{\mathit{r}}$b\ensuremath{\Vert}\ensuremath{\gg}1, where b is the confocal parameter of the focused laser beams. Strong absorption of the four-wave-mixing field is shown not to be necessary for strong destructive interference with focused laser beams when the phase mismatch is large. This work also suggests an explanation for earlier experiments where the presence of a four-photon resonance enabled the generation of third-harmonic light in a positively dispersive wavelength region. We argue that this process can occur when the laser used to achieve the four-photon resonance is focused on the small z (z is the coordinate in the direction of propagation) side of the focal point of the laser responsible for the third-harmonic generation. In this way the absorption of the third-harmonic light on one side of the focal point is made much stronger than on the other side. Correspondingly, contributions to the third-harmonic field from the two sides of the focal point are unequal and cannot undergo complete destructive interference as would otherwise occur in a positively dispersive region.

Physical Review ADec 1, 199119 citations

Suppression of a four-photon resonance by four-wave mixing near an intermediate three-photon resonance

Roger C. Hart, W. R. Garrett, M. G. Payne

We use resonance ionization involving two colors in single-pass and retroreflected geometries to study the suppression of excitation of a four-photon resonance by an interference involving four-wave sum-frequency generation occurring near an intermediate three-photon resonance. The 6p[1/2](J=0) state of xenon is excited by three blue photons plus one infrared photon. One beam, focused to ${\mathit{I}}_{1}$ \ensuremath{\simeq}7\ifmmode\times\else\texttimes\fi{} ${10}^{9}$ W/ ${\mathrm{cm}}^{2}$ , is nearly three-photon resonant with the 6s[3/2](J=1) resonance; the second, unfocused beam ( ${\mathit{I}}_{2}$ \ensuremath{\simeq}2\ifmmode\times\else\texttimes\fi{} ${10}^{7}$ W/ ${\mathrm{cm}}^{2}$ ) is tuned to maintain exact four-photon resonance with the 6p[1/2](J=1) state. One additional blue photon ionizes from the four-photon level. Third-harmonic light is generated by the first, nearly three-photon-resonant beam by four-wave sum-frequency mixing. One third-harmonic photon plus one photon from the second laser form a second excitation pathway to the four-photon level; destructive interference between the two pathways results in a reduction in the observed ionization. The degree of reduction depends on the xenon density and the detuning (both positive and negative) from three-photon resonance. This interference may be overcome by retroreflecting the nearly three-photon-resonant beam to provide an additional excitation pathway which generates no third harmonic.The study provides detailed information on the pressure-dependent range from exact resonance over which the familiar three-photon cancellation effect is operative; it shows that the interference occurs in high- and low-energy regions about three-photon resonance; and it establishes that interference is produced for large values of the phase mismatch even if the absorption of the interfering field is low. We compare our measurements of the reduction in ionization with predictions published by us elsewhere [M. G. Payne, J. C. Miller, R. C. Hart, and W. R. Garrett, Phys. Rev. A 44, 7684 (1991)]; excellent agreement is observed. We also report the observation of suppression of pressure-induced wing absorption into the three-photon state observed in a classic ``hybrid'' resonance mode of excitation.We use resonance ionization involving two colors in single-pass and retroreflected geometries to study the suppression of excitation of a four-photon resonance by an interference involving four-wave sum-frequency generation occurring near an intermediate three-photon resonance. The 6p[1/2](J=0) state of xenon is excited by three blue photons plus one infrared photon. One beam, focused to ${\mathit{I}}_{1}$\ensuremath{\simeq}7\ifmmode\times\else\texttimes\fi{}${10}^{9}$ W/${\mathrm{cm}}^{2}$, is nearly three-photon resonant with the 6s[3/2](J=1) resonance; the second, unfocused beam (${\mathit{I}}_{2}$\ensuremath{\simeq}2\ifmmode\times\else\texttimes\fi{}${10}^{7}$ W/${\mathrm{cm}}^{2}$) is tuned to maintain exact four-photon resonance with the 6p[1/2](J=1) state. One additional blue photon ionizes from the four-photon level. Third-harmonic light is generated by the first, nearly three-photon-resonant beam by four-wave sum-frequency mixing. One third-harmonic photon plus one photon from the second laser form a second excitation pathway to the four-photon level; destructive interference between the two pathways results in a reduction in the observed ionization. The degree of reduction depends on the xenon density and the detuning (both positive and negative) from three-photon resonance. This interference may be overcome by retroreflecting the nearly three-photon-resonant beam to provide an additional excitation pathway which generates no third harmonic.The study provides detailed information on the pressure-dependent range from exact resonance over which the familiar three-photon cancellation effect is operative; it shows that the interference occurs in high- and low-energy regions about three-photon resonance; and it establishes that interference is produced for large values of the phase mismatch even if the absorption of the interfering field is low. We compare our measurements of the reduction in ionization with predictions published by us elsewhere [M. G. Payne, J. C. Miller, R. C. Hart, and W. R. Garrett, Phys. Rev. A 44, 7684 (1991)]; excellent agreement is observed. We also report the observation of suppression of pressure-induced wing absorption into the three-photon state observed in a classic ``hybrid'' resonance mode of excitation.

Physical Review AOct 1, 199212 citations

Level splitting effects in CW resonant four-wave mixing

Sergei A Babin, S.I. Kalukov, U. Hinze +2 more

Summary form only given. Various schemes of resonant frequency conversion using four-wave mixing (FWM) have been investigated recently. For example, sum-frequency FWM in Hg atoms has been used for generation of CW radiation at 121.56 nm, corresponding to the Lyman-/spl alpha/ line of hydrogen and efficient difference frequency mixing has been demonstrated in double-/spl Lambda/ level configurations of Na/sub 2/ molecules. We present novel investigations on the resonance structure of the FWM-spectra in the case of up-conversion in a double-/spl Lambda/ scheme realized in Na/sub 2/.Summary form only given. Various schemes of resonant frequency conversion using four-wave mixing (FWM) have been investigated recently. For example, sum-frequency FWM in Hg atoms has been used for generation of CW radiation at 121.56 nm, corresponding to the Lyman-/spl alpha/ line of hydrogen and efficient difference frequency mixing has been demonstrated in double-/spl Lambda/ level configurations of Na/sub 2/ molecules. We present novel investigations on the resonance structure of the FWM-spectra in the case of up-conversion in a double-/spl Lambda/ scheme realized in Na/sub 2/.

Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)Nov 11, 20020 citations

Role of atomic coherence effects in four-wave mixing using autoionizing resonances

M. Anscombe, Rebeca de Nalda, İbrahim Küçükkara +1 more

The generation of tunable, nanosecond-pulsed extreme-ultraviolet (EUV) light $(84.92\mathrm{nm}$ to $84.97\mathrm{nm}$ $\ensuremath{\sim}14.6\mathrm{eV})$ using four-wave mixing in optically deep krypton gas was investigated experimentally and theoretically. The sum-frequency mixing scheme generated light from two overlapping autoionizing resonances, ${17s}^{\ensuremath{'}}$ and ${15d}^{\ensuremath{'}}$. We investigated whether the laser-induced atomic coherence effect of electromagnetically induced transparency (EIT) could enhance the intensity of the EUV light generated. The maximum EUV output was seen from the region where the ${15d}^{\ensuremath{'}}$ autoionizing resonance has a transparency window due to Fano-type quantum interference. An analytical model using appropriate atomic parameters explains how background absorption can prevent EIT enhancement of EUV generation; and shows how a background Raman-like coupling term in the nonlinear susceptibility can well describe the measured EUV generation spectrum.The generation of tunable, nanosecond-pulsed extreme-ultraviolet (EUV) light $(84.92\mathrm{nm}$ to $84.97\mathrm{nm}$ $\ensuremath{\sim}14.6\mathrm{eV})$ using four-wave mixing in optically deep krypton gas was investigated experimentally and theoretically. The sum-frequency mixing scheme generated light from two overlapping autoionizing resonances, ${17s}^{\ensuremath{'}}$ and ${15d}^{\ensuremath{'}}$. We investigated whether the laser-induced atomic coherence effect of electromagnetically induced transparency (EIT) could enhance the intensity of the EUV light generated. The maximum EUV output was seen from the region where the ${15d}^{\ensuremath{'}}$ autoionizing resonance has a transparency window due to Fano-type quantum interference. An analytical model using appropriate atomic parameters explains how background absorption can prevent EIT enhancement of EUV generation; and shows how a background Raman-like coupling term in the nonlinear susceptibility can well describe the measured EUV generation spectrum.

Physical Review AOct 8, 20032 citations

Enhanced production of coherent vuv radiation by four-wave mixing in Sr vapor

Gary C. Bjorklund, John E. Bjorkholm, Richard R. Freeman +1 more

Applied Physics LettersSep 1, 197732 citations

{\mathit{k}}_{\mathit{r}}

L\ensuremath{\Vert}\ensuremath{\gg}1, where \ensuremath{\Delta}

{\mathit{k}}_{\mathit{r}}

is the mismatch and L is the length of the path of the laser beams in the gas. With focused laser beams large differences occur between ionization with unidirectional beams and with counterpropagating laser beams when \ensuremath{\Vert}\ensuremath{\Delta}

{\mathit{k}}_{\mathit{r}}

b\ensuremath{\Vert}\ensuremath{\gg}1, where b is the confocal parameter of the focused laser beams. Strong absorption of the four-wave-mixing field is shown not to be necessary for strong destructive interference with focused laser beams when the phase mismatch is large. This work also suggests an explanation for earlier experiments where the presence of a four-photon resonance enabled the generation of third-harmonic light in a positively dispersive wavelength region. We argue that this process can occur when the laser used to achieve the four-photon resonance is focused on the small z (z is the coordinate in the direction of propagation) side of the focal point of the laser responsible for the third-harmonic generation. In this way the absorption of the third-harmonic light on one side of the focal point is made much stronger than on the other side. Correspondingly, contributions to the third-harmonic field from the two sides of the focal point are unequal and cannot undergo complete destructive interference as would otherwise occur in a positively dispersive region.

{\mathit{I}}_{1}

\ensuremath{\simeq}7\ifmmode\times\else\texttimes\fi{}

{10}^{9}

{\mathrm{cm}}^{2}

, is nearly three-photon resonant with the 6s[3/2](J=1) resonance; the second, unfocused beam (

{\mathit{I}}_{2}

\ensuremath{\simeq}2\ifmmode\times\else\texttimes\fi{}

{10}^{7}

{\mathrm{cm}}^{2}

) is tuned to maintain exact four-photon resonance with the 6p[1/2](J=1) state. One additional blue photon ionizes from the four-photon level. Third-harmonic light is generated by the first, nearly three-photon-resonant beam by four-wave sum-frequency mixing. One third-harmonic photon plus one photon from the second laser form a second excitation pathway to the four-photon level; destructive interference between the two pathways results in a reduction in the observed ionization. The degree of reduction depends on the xenon density and the detuning (both positive and negative) from three-photon resonance. This interference may be overcome by retroreflecting the nearly three-photon-resonant beam to provide an additional excitation pathway which generates no third harmonic.The study provides detailed information on the pressure-dependent range from exact resonance over which the familiar three-photon cancellation effect is operative; it shows that the interference occurs in high- and low-energy regions about three-photon resonance; and it establishes that interference is produced for large values of the phase mismatch even if the absorption of the interfering field is low. We compare our measurements of the reduction in ionization with predictions published by us elsewhere [M. G. Payne, J. C. Miller, R. C. Hart, and W. R. Garrett, Phys. Rev. A 44, 7684 (1991)]; excellent agreement is observed. We also report the observation of suppression of pressure-induced wing absorption into the three-photon state observed in a classic ``hybrid'' resonance mode of excitation.

The generation of tunable, nanosecond-pulsed extreme-ultraviolet (EUV) light

(84.92\mathrm{nm}

84.97\mathrm{nm}

$\ensuremath{\sim}14.6\mathrm{eV})$ using four-wave mixing in optically deep krypton gas was investigated experimentally and theoretically. The sum-frequency mixing scheme generated light from two overlapping autoionizing resonances, ${17s}^{\ensuremath{'}}$ and ${15d}^{\ensuremath{'}}$. We investigated whether the laser-induced atomic coherence effect of electromagnetically induced transparency (EIT) could enhance the intensity of the EUV light generated. The maximum EUV output was seen from the region where the ${15d}^{\ensuremath{'}}$ autoionizing resonance has a transparency window due to Fano-type quantum interference. An analytical model using appropriate atomic parameters explains how background absorption can prevent EIT enhancement of EUV generation; and shows how a background Raman-like coupling term in the nonlinear susceptibility can well describe the measured EUV generation spectrum.