The authors have observed the spectra for the production of Ba + and Ba 2+ between 550 and 670 nm. They observe sharp resonances for the production of Ba 2+ which generally do not coincide with peaks in the Ba + production. While they can easily assign most of the resonances in the Ba + spectra to two-photon resonances with bound states it is not possible to assign most of the Ba 2+ peaks to two- or three-photon Ba + transitions. This suggests that the production of Ba 2+ proceeds both via Ba autoionising states and low-lying Ba + states.The authors have observed the spectra for the production of Ba + and Ba 2+ between 550 and 670 nm. They observe sharp resonances for the production of Ba 2+ which generally do not coincide with peaks in the Ba + production. While they can easily assign most of the resonances in the Ba + spectra to two-photon resonances with bound states it is not possible to assign most of the Ba 2+ peaks to two- or three-photon Ba + transitions. This suggests that the production of Ba 2+ proceeds both via Ba autoionising states and low-lying Ba + states.

Journal of Physics B Atomic and Molecular PhysicsNov 14, 198525 citations

Double-quantum photon echo in an adiabatic-vector-model approximation

Steven Aoki

The possible generation of photon echoes is discussed for a system where the incident radiation resonantly drives two-photon transitions. Use of the adiabatic-vector-model approximation of Grischkowsky, Loy, and Liao allows echo behavior to be calculated in a multilevel system by methods similar to those previously employed for two-level atoms. We find that observation of the double-quantum photon echo requires the presence of a nonresonant probe field at the time of formation of the echo pulse. The echo then radiates at the sum and difference of the probe and two-photon frequencies. As an example, we consider a possible experimental arrangement for the detection of double-quantum photon echoes in Rb vapor.The possible generation of photon echoes is discussed for a system where the incident radiation resonantly drives two-photon transitions. Use of the adiabatic-vector-model approximation of Grischkowsky, Loy, and Liao allows echo behavior to be calculated in a multilevel system by methods similar to those previously employed for two-level atoms. We find that observation of the double-quantum photon echo requires the presence of a nonresonant probe field at the time of formation of the echo pulse. The echo then radiates at the sum and difference of the probe and two-photon frequencies. As an example, we consider a possible experimental arrangement for the detection of double-quantum photon echoes in Rb vapor.

Physical Review ADec 1, 19769 citations

An Investigation on the Double Nature of Photons

Pasquale Acquaro

Lecture notes in electrical engineeringNov 30, 20111 citation

Investigation of the four-photon resonance scattering of light

Iu. M. Kirin, Sergey G. Rautian, Vladimir P. Safonov +1 more

Zhurnal Eksperimentalnoi i Teoreticheskoi FizikiDec 1, 19740 citations

Sequential double photodetachment of He− in elliptically polarized laser fields

Matthieu Génévriez, Kevin M. Dunseath, Mariko Terao-Dunseath +1 more

Four-photon double detachment of the helium negative ion is investigated experimentally and theoretically for photon energies where the transient helium atom is in the $1s2s\phantom{\rule{0.16em}{0ex}}^{3}S$ or $1s2p\phantom{\rule{0.16em}{0ex}}^{3}P^{\mathrm{o}}$ states, which subsequently ionize by absorption of three photons. Ionization is enhanced by intermediate resonances, giving rise to series of peaks in the ${\mathrm{He}}^{+}$ spectrum, which we study in detail. The ${\mathrm{He}}^{+}$ yield is measured in the wavelength ranges from 530 to 560 nm and from 685 to 730 nm and for various polarizations of the laser light. Double detachment is treated theoretically as a sequential process, within the framework of $R$ -matrix theory for the first step and effective Hamiltonian theory for the second step. Experimental conditions are accurately modeled, and the measured and simulated yields are in good qualitative and, in some cases, quantitative agreement. Resonances in the double detachment spectra can be attributed to well-defined Rydberg states of the transient atom. The double detachment yield exhibits a strong dependence on the laser polarization which can be related to the magnetic quantum number of the intermediate atomic state. We also investigate the possibility of nonsequential double detachment with a two-color experiment but observe no evidence for it.Four-photon double detachment of the helium negative ion is investigated experimentally and theoretically for photon energies where the transient helium atom is in the $1s2s\phantom{\rule{0.16em}{0ex}}^{3}S$ or $1s2p\phantom{\rule{0.16em}{0ex}}^{3}P^{\mathrm{o}}$ states, which subsequently ionize by absorption of three photons. Ionization is enhanced by intermediate resonances, giving rise to series of peaks in the ${\mathrm{He}}^{+}$ spectrum, which we study in detail. The ${\mathrm{He}}^{+}$ yield is measured in the wavelength ranges from 530 to 560 nm and from 685 to 730 nm and for various polarizations of the laser light. Double detachment is treated theoretically as a sequential process, within the framework of $R$-matrix theory for the first step and effective Hamiltonian theory for the second step. Experimental conditions are accurately modeled, and the measured and simulated yields are in good qualitative and, in some cases, quantitative agreement. Resonances in the double detachment spectra can be attributed to well-defined Rydberg states of the transient atom. The double detachment yield exhibits a strong dependence on the laser polarization which can be related to the magnetic quantum number of the intermediate atomic state. We also investigate the possibility of nonsequential double detachment with a two-color experiment but observe no evidence for it.

Physical Review AFeb 13, 20180 citations

Four-photon double detachment of the helium negative ion is investigated experimentally and theoretically for photon energies where the transient helium atom is in the

1s2s\phantom{\rule{0.16em}{0ex}}^{3}S

1s2p\phantom{\rule{0.16em}{0ex}}^{3}P^{\mathrm{o}}

states, which subsequently ionize by absorption of three photons. Ionization is enhanced by intermediate resonances, giving rise to series of peaks in the

{\mathrm{He}}^{+}

spectrum, which we study in detail. The

{\mathrm{He}}^{+}

yield is measured in the wavelength ranges from 530 to 560 nm and from 685 to 730 nm and for various polarizations of the laser light. Double detachment is treated theoretically as a sequential process, within the framework of

R

-matrix theory for the first step and effective Hamiltonian theory for the second step. Experimental conditions are accurately modeled, and the measured and simulated yields are in good qualitative and, in some cases, quantitative agreement. Resonances in the double detachment spectra can be attributed to well-defined Rydberg states of the transient atom. The double detachment yield exhibits a strong dependence on the laser polarization which can be related to the magnetic quantum number of the intermediate atomic state. We also investigate the possibility of nonsequential double detachment with a two-color experiment but observe no evidence for it.