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

Multiphoton Ionization and Third Harmonic Generation in Alkali Atoms

R. N. Compton, Michael A. Duncan

Abstract Experiments involving resonantly enhanced multiphoton ionization (REMPI) of alkali atoms contained in a heat pipe are discussed with reference to the quantum defect theory modification of the hydrogen atom energy levels. Quantum defects for the ns and nd levels are extracted from the data. This experiment is an excellent introduction to atomic spectroscopy and the selection rules involved. Ionization potentials are extracted from the Rydberg spectra. In the second part of this chapter a Raman shifter is employed to produce IR photons for multiphoton excitation of the low-lying p states of cesium. Three-photon excitation also produces third harmonic generation. The use of heat pipes for the production of alkali metal atom vapor is discussed as well as the use of a simple pick-up wire for ion detection.Abstract Experiments involving resonantly enhanced multiphoton ionization (REMPI) of alkali atoms contained in a heat pipe are discussed with reference to the quantum defect theory modification of the hydrogen atom energy levels. Quantum defects for the ns and nd levels are extracted from the data. This experiment is an excellent introduction to atomic spectroscopy and the selection rules involved. Ionization potentials are extracted from the Rydberg spectra. In the second part of this chapter a Raman shifter is employed to produce IR photons for multiphoton excitation of the low-lying p states of cesium. Three-photon excitation also produces third harmonic generation. The use of heat pipes for the production of alkali metal atom vapor is discussed as well as the use of a simple pick-up wire for ion detection.

Nov 27, 20240 citations

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

Perry R. Blazewicz, John C. Miller

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.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.

Physical Review ASep 1, 198819 citations

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.

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.