Physical Review A

Nonlinear optical processes in xenon and krypton studied by two-color multiphoton ionization

Perry R. Blazewicz, John C. Miller

Published Sep 1, 1988• 19 citations

Abstract

Multiphoton ionization (MPI) and third-harmonic generation (THG) in xenon and krypton have been studied via three-photon resonance with the xenon 6s'${[1/2]}_{1}^{0}$ and krypton 5s${[(3/2]}_{1}^{0}$ states. A second, tunable dye laser is used to couple these states to higher-lying even-parity states. Observations are reported regarding the third-harmonic related cancellation of the intermediate s-state population and the mechanisms of population of the final states. Effects of the four-photon resonance on THG are detailed. Changes induced by the second laser reduce THG in normally favorable regions and enable it in otherwise forbidden regions. Striking effects in the MPI spectra due to the changes induced in THG are reported.

DOI: 10.1103/physreva.38.2863

Related papers

Two-color multiphoton ionization of xenon

R. N. Compton, John C. Miller

Journal of the Optical Society of America BFeb 1, 198537 citations

Third-harmonic generation and multiphoton ionization in rare gases

John C. Miller, R. N. Compton

Physical Review AApr 1, 1982102 citations

Laser-induced third-harmonic generation in forbidden regions

Perry R. Blazewicz, M. G. Payne, W. R. Garrett +1 more

Physical Review ADec 1, 198616 citations

Two-photon resonant multiphoton ionization and stimulated emission in krypton and xenon

John C. Miller

Physical Review ADec 1, 198970 citations

Interference between nearly resonant three-photon excitation and third-harmonic generation probed by the cancellation of four-photon resonances

X. Xing, Dimitrios Charalambidis, E. Koutsourelaki +1 more

Physical Review AMar 1, 19939 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

Physical Review A

Nonlinear optical processes in xenon and krypton studied by two-color multiphoton ionization

Perry R. Blazewicz, John C. Miller

Published Sep 1, 1988• 19 citations

Publisher

Abstract

Multiphoton ionization (MPI) and third-harmonic generation (THG) in xenon and krypton have been studied via three-photon resonance with the xenon 6s'

{[1/2]}_{1}^{0}

and krypton 5s

{[(3/2]}_{1}^{0}

states. A second, tunable dye laser is used to couple these states to higher-lying even-parity states. Observations are reported regarding the third-harmonic related cancellation of the intermediate s-state population and the mechanisms of population of the final states. Effects of the four-photon resonance on THG are detailed. Changes induced by the second laser reduce THG in normally favorable regions and enable it in otherwise forbidden regions. Striking effects in the MPI spectra due to the changes induced in THG are reported.

DOI: 10.1103/physreva.38.2863

Related papers

Two-color multiphoton ionization of xenon

R. N. Compton, John C. Miller

Two independently tunable, linearly polarized dye lasers have been used to study multiphoton ionization of gaseous xenon. One laser is tuned near three-photon resonance with the allowed 6s[3/2]J=1° resonance, which is not observed with one laser at these pressures because of the destructive interference between the three-photon-excitation and third-harmonic-excitation pathways to the 6s[3/2]J=1° state. The second laser is tuned to resonance with higher allowed np and np′ states of xenon. The missing ionization signal is seen to be dramatically restored by the addition of the second laser beam; however, the signal again disappears as the pressure is increased. These results are discussed in relation to recent experimental and theoretical studies of cancellation effects between three-photon excitation and third-harmonic generation. Spectroscopic information obtained from tuning each dye laser, together with data on the angular distributions resulting from rotating the plane of polarization of one laser relative to that of the second laser, clearly shows that two different ionization mechanisms are operative. In addition, these experiments unambiguously illustrate the importance of dissociative ionization of quasi-dimers of xenon over a rather broad frequency range.Two independently tunable, linearly polarized dye lasers have been used to study multiphoton ionization of gaseous xenon. One laser is tuned near three-photon resonance with the allowed 6s[3/2]J=1° resonance, which is not observed with one laser at these pressures because of the destructive interference between the three-photon-excitation and third-harmonic-excitation pathways to the 6s[3/2]J=1° state. The second laser is tuned to resonance with higher allowed np and np′ states of xenon. The missing ionization signal is seen to be dramatically restored by the addition of the second laser beam; however, the signal again disappears as the pressure is increased. These results are discussed in relation to recent experimental and theoretical studies of cancellation effects between three-photon excitation and third-harmonic generation. Spectroscopic information obtained from tuning each dye laser, together with data on the angular distributions resulting from rotating the plane of polarization of one laser relative to that of the second laser, clearly shows that two different ionization mechanisms are operative. In addition, these experiments unambiguously illustrate the importance of dissociative ionization of quasi-dimers of xenon over a rather broad frequency range.

Journal of the Optical Society of America BFeb 1, 198537 citations

Third-harmonic generation and multiphoton ionization in rare gases

John C. Miller, R. N. Compton

Resonantly enhanced multiphoton ionization (MPI) and third-harmonic generation (THG) have been concurrently studied in the rare gases, xenon, krypton, and argon. The disappearance with increasing pressure of the MPI signals resonant with the three-photon allowed $6s$ , $5s$ , and $4s$ states, respectively, of the rare gases is linked to the appearance of THG. Conversely, THG is shown to be partially quenched at certain wavelengths by one- and two-photon absorption leading to ionization.Resonantly enhanced multiphoton ionization (MPI) and third-harmonic generation (THG) have been concurrently studied in the rare gases, xenon, krypton, and argon. The disappearance with increasing pressure of the MPI signals resonant with the three-photon allowed $6s$, $5s$, and $4s$ states, respectively, of the rare gases is linked to the appearance of THG. Conversely, THG is shown to be partially quenched at certain wavelengths by one- and two-photon absorption leading to ionization.

Physical Review AApr 1, 1982102 citations

Laser-induced third-harmonic generation in forbidden regions

Perry R. Blazewicz, M. G. Payne, W. R. Garrett +1 more

New observations are reported of tunable vacuum ultraviolet light generated in the forbidden region to the red of the xenon $6{s}^{\ensuremath{'}}{[\frac{1}{2}]}_{1}^{0}$ state due to the introduction of a second, resonant laser field. Striking observations of double-resonant ionization signals on the blue side of the xenon $6{s}^{\ensuremath{'}}$ level are also reported. Both sets of data are interpreted in terms of the changes in phase matching and the nonlinear susceptibility induced in the medium by the second laser. These changes are successfully analyzed in terms of the ac Stark effect in the three-photon level due to the second laser field.New observations are reported of tunable vacuum ultraviolet light generated in the forbidden region to the red of the xenon $6{s}^{\ensuremath{'}}{[\frac{1}{2}]}_{1}^{0}$ state due to the introduction of a second, resonant laser field. Striking observations of double-resonant ionization signals on the blue side of the xenon $6{s}^{\ensuremath{'}}$ level are also reported. Both sets of data are interpreted in terms of the changes in phase matching and the nonlinear susceptibility induced in the medium by the second laser. These changes are successfully analyzed in terms of the ac Stark effect in the three-photon level due to the second laser field.

Physical Review ADec 1, 198616 citations

Two-photon resonant multiphoton ionization and stimulated emission in krypton and xenon

John C. Miller

Forward- and backward-directed, stimulated emissions have been observed following two-photon pumping of the 5p states of krypton and the 6p', 7p, 8p, and 4f states of xenon. Multiphoton ionization spectra are also obtained and compared with the photon-detected excitation spectra. In krypton coherent emissions from the 5p states to the 5s are observed, and for xenon many p\ensuremath{\rightarrow}s, d\ensuremath{\rightarrow}p, and f\ensuremath{\rightarrow}d cascade emissions are observed. By analogy to the well-studied alkali-metal and alkaline-earth examples, the emissions are assigned as amplified spontaneous emission. Several intensity anomalies in the xenon p\ensuremath{\rightarrow}s emissions are not understood at present. Interference effects due to coherent cancellation between competing excitation pathways may be occurring.Forward- and backward-directed, stimulated emissions have been observed following two-photon pumping of the 5p states of krypton and the 6p', 7p, 8p, and 4f states of xenon. Multiphoton ionization spectra are also obtained and compared with the photon-detected excitation spectra. In krypton coherent emissions from the 5p states to the 5s are observed, and for xenon many p\ensuremath{\rightarrow}s, d\ensuremath{\rightarrow}p, and f\ensuremath{\rightarrow}d cascade emissions are observed. By analogy to the well-studied alkali-metal and alkaline-earth examples, the emissions are assigned as amplified spontaneous emission. Several intensity anomalies in the xenon p\ensuremath{\rightarrow}s emissions are not understood at present. Interference effects due to coherent cancellation between competing excitation pathways may be occurring.

Physical Review ADec 1, 198970 citations

Interference between nearly resonant three-photon excitation and third-harmonic generation probed by the cancellation of four-photon resonances

X. Xing, Dimitrios Charalambidis, E. Koutsourelaki +1 more

The destructive interference between the three-photon and the third-harmonic one-photon absorption in the vicinity of the 6s[3/2 ${]}_{1}$ state of Xe has been studied in the resonantly enhanced multiphoton ionization via nf states, through the cancellation of the nf, J=2 resonances of the spectrum, accessible by four-photon absorption. The gas-pressure, i.e., phase-matching, dependence of the three-photon detuning range from the 6s[3/2 ${]}_{1}$ state for which cancellation occurs has been investigated in one- and two-color experiments, including positive detuning from this state in positively dispersive regions. For obtaining cancellation, the theoretically predicted requirement of optically thick medium at the third-harmonic frequency is corroborated by present observations for negative detunings. The different cancellation behavior of the nf[3/2 ${]}_{2}$ and nf[5/2 ${]}_{2}$ states observed indicates the dependence of the effect on the atomic parameters of the coupled four-photon resonance. The experimental results are found to be in partial agreement with existing theoretical models.The destructive interference between the three-photon and the third-harmonic one-photon absorption in the vicinity of the 6s[3/2${]}_{1}$ state of Xe has been studied in the resonantly enhanced multiphoton ionization via nf states, through the cancellation of the nf, J=2 resonances of the spectrum, accessible by four-photon absorption. The gas-pressure, i.e., phase-matching, dependence of the three-photon detuning range from the 6s[3/2${]}_{1}$ state for which cancellation occurs has been investigated in one- and two-color experiments, including positive detuning from this state in positively dispersive regions. For obtaining cancellation, the theoretically predicted requirement of optically thick medium at the third-harmonic frequency is corroborated by present observations for negative detunings. The different cancellation behavior of the nf[3/2${]}_{2}$ and nf[5/2${]}_{2}$ states observed indicates the dependence of the effect on the atomic parameters of the coupled four-photon resonance. The experimental results are found to be in partial agreement with existing theoretical models.

Physical Review AMar 1, 19939 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

Multiphoton ionization (MPI) and third-harmonic generation (THG) in xenon and krypton have been studied via three-photon resonance with the xenon 6s'

{[1/2]}_{1}^{0}

and krypton 5s

{[(3/2]}_{1}^{0}

6s

5s

, and

4s

states, respectively, of the rare gases is linked to the appearance of THG. Conversely, THG is shown to be partially quenched at certain wavelengths by one- and two-photon absorption leading to ionization.

The destructive interference between the three-photon and the third-harmonic one-photon absorption in the vicinity of the 6s[3/2

{]}_{1}

state of Xe has been studied in the resonantly enhanced multiphoton ionization via nf states, through the cancellation of the nf, J=2 resonances of the spectrum, accessible by four-photon absorption. The gas-pressure, i.e., phase-matching, dependence of the three-photon detuning range from the 6s[3/2

{]}_{1}

state for which cancellation occurs has been investigated in one- and two-color experiments, including positive detuning from this state in positively dispersive regions. For obtaining cancellation, the theoretically predicted requirement of optically thick medium at the third-harmonic frequency is corroborated by present observations for negative detunings. The different cancellation behavior of the nf[3/2

{]}_{2}

and nf[5/2

{]}_{2}

states observed indicates the dependence of the effect on the atomic parameters of the coupled four-photon resonance. The experimental results are found to be in partial agreement with existing theoretical models.

{\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.