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

Journal of Physics B Atomic and Molecular Physics

Theory of two-photon resonant up-conversion with ultrashort pulses. II. Non-synchronous generation

J N Elgin, G.H.C. New, P. Smith

Published Apr 28, 1980• 7 citations
Publisher

Abstract

For pt.I see ibid., vol.11, no.19, p.8439 (1978). This is the second in a series of papers in which various theoretical aspects of two-photon resonant up-conversion with ultrashort pulses are examined. The first paper in the series was concerned with the case of third harmonic generation. The authors study the more general two-photon resonant four-wave process ( omega a + omega a )+ omega c to omega d for the case where the pulse at omega a is not time synchronised with the pulse at omega c .

DOI
10.1088/0022-3700/13/8/020

Related papers

Harmonic generation in coherent two-photon interaction between high-power optical pulses and resonant media

I A Poluéktov, A. Nazarkin

A theoretical investigation is made of collinear propagation of high-power optical pulses through a medium under conditions of two-photon resonance ω 0 ± ω s ≈ ω 21 ( ω 0 and ω s are the pulse frequencies, ω 21 is the frequency of an atomic transition in the medium). It is assumed that the condition for coherent interaction τ 0 , τ s < T 2 is satisfied ( τ 0 and τ s are the pulse durations at the entrance, T 2 is the phase relaxation time of the medium). By means of numerical integration of equations for the fields and the medium, it is shown that efficient generation of the harmonics ω 1 = 2 ω 0 ± ω s , ω 2 = 2 ω s ± ω 0 is possible under short and ultrashort pulse conditions.

Soviet Journal of Quantum Electronics•Feb 28, 1981•4 citations

Theory of two-photon amplification with ultrashort pulses

J N Elgin, T.B. O'Hare, G.H.C. New

The process of two-photon amplification of ultrashort pulses is analysed for the case where simultaneous single-photon ionisation occurs from the upper resonant level.

Journal of Physics B Atomic and Molecular Physics•Jan 14, 1981•0 citations

Multiphoton Coherences

J.-C. Diels, Nandini Mukherjee, Arindum Mukherjee

Multiphoton coherent interaction effects are investigated in atoms and molecules. It is demonstrated theoretically as well as experimentally that, in the presence of a two photon resonance, maximum conversion efficiency can be achieved using energy preserving pulse sequences, in condition of coherent interaction. However, highest conversion efficiencies are obtained with weak two photon resonances. A study of four photon resonant coherent interaction in mercury points to a peculiar quenching of the interaction by the generated third harmonic. Four photon resonant coherent interaction is also investigated in molecules, where it is shown that an input signal can be found that results in selective excitation of the upper levels.

Physica Scripta•Jan 1, 1988•1 citation

Two-photon self-induced transparency in a resonant medium. II. Transient pulse behaviour

N Tan-no, Kenichi Yokoto, Humio Inaba

For pt.I see ibid., vol.8, no.3, 339 (1975). The transient behaviour of two short optical pulses in two-photon coherent propagation is obtained by calculating numerically the coherent propagation equations which couple the two electromagnetic pulses and the atomic system in self-consistent fashion. The coherent interaction of the two different frequency pulses gives rise to lossless propagation in the absorptive medium. This description is characterized by a two-photon area theorem. Novel coherent propagation effects of peak amplification and multiple pulse breakup are found. These effects are ascribed to two-photon self-induced transparency analogous to that of a one-photon transition in a two-level system. A difference of input intensity between the two different frequency pulses yields curious modulation effects involving sharp peak amplification and marked pulse breakup for the low-intensity input. In contrast, the high-intensity input pulse displays a smooth variation with distance and time. Low-loss pulse transmission above threshold, and pulse advance and delay are found for the present case in contrast to that for one-photon self-induced transparency.

Journal of Physics B Atomic and Molecular Physics•Feb 21, 1975•10 citations

Coherent control of third-harmonic generation and multiphoton ionization: Experimental and theoretical studies

Roberto Buffa, R. Eramo, CAVALIERI, STEFANO +1 more

The effect of temporal coherent control on the two-photon-resonant third-harmonic generation and multiphoton ionization into the continuum states of an atomic system is experimentally and theoretically investigated by means of a pair of partially incoherent, identical laser pulses. The evidence of quantum interference as a function of the delay between the pulses is reported. The transition from the resonant to the nonresonant case is also shown. The obtained results agree with the prediction of a theoretical model showing that the onset of quantum interference appears to be related to the coherence time of the laser radiation, which is much shorter than the pulse duration.

•Jan 1, 2005•0 citations

Theory of two-photon resonant third-harmonic generation with ultrashort pulses. III. Index mismatching, detuning and spectral effects

J N Elgin, G.H.C. New, J. M. Catherall

The analysis of two-photon resonant third-harmonic generation is generalised to include, in particular, the effects of imperfect index matching and two-photon tuning. Furthermore, whereas previously the authors considered only the temporal properties of the generated harmonic signal, here is spectral characteristics are also considered. The authors comment on a discrepancy between the predictions of semiclassical and quantised field formalisms. In the semiclassical analysis, it is shown that for large energy input pulses the harmonic spectrum is double peaked even near exact resonance and that this structure can be interpreted in terms of transitions between sets of doublet states of the Autler-Townes (1955) type. In a quantised field formalism, however, the picture is radically altered near exact resonance where a three-peaked spectrum is predicted.

Journal of Physics B Atomic and Molecular Physics•Aug 14, 1980•4 citations
For pt.I see ibid., vol.11, no.19, p.8439 (1978). This is the second in a series of papers in which various theoretical aspects of two-photon resonant up-conversion with ultrashort pulses are examined. The first paper in the series was concerned with the case of third harmonic generation. The authors study the more general two-photon resonant four-wave process ( omega a + omega a )+ omega c to omega d for the case where the pulse at omega a is not time synchronised with the pulse at omega c .
A theoretical investigation is made of collinear propagation of high-power optical pulses through a medium under conditions of two-photon resonance ω 0 ± ω s ≈ ω 21 ( ω 0 and ω s are the pulse frequencies, ω 21 is the frequency of an atomic transition in the medium). It is assumed that the condition for coherent interaction τ 0 , τ s < T 2 is satisfied ( τ 0 and τ s are the pulse durations at the entrance, T 2 is the phase relaxation time of the medium). By means of numerical integration of equations for the fields and the medium, it is shown that efficient generation of the harmonics ω 1 = 2 ω 0 ± ω s , ω 2 = 2 ω s ± ω 0 is possible under short and ultrashort pulse conditions.
Multiphoton coherent interaction effects are investigated in atoms and molecules. It is demonstrated theoretically as well as experimentally that, in the presence of a two photon resonance, maximum conversion efficiency can be achieved using energy preserving pulse sequences, in condition of coherent interaction. However, highest conversion efficiencies are obtained with weak two photon resonances. A study of four photon resonant coherent interaction in mercury points to a peculiar quenching of the interaction by the generated third harmonic. Four photon resonant coherent interaction is also investigated in molecules, where it is shown that an input signal can be found that results in selective excitation of the upper levels.
For pt.I see ibid., vol.8, no.3, 339 (1975). The transient behaviour of two short optical pulses in two-photon coherent propagation is obtained by calculating numerically the coherent propagation equations which couple the two electromagnetic pulses and the atomic system in self-consistent fashion. The coherent interaction of the two different frequency pulses gives rise to lossless propagation in the absorptive medium. This description is characterized by a two-photon area theorem. Novel coherent propagation effects of peak amplification and multiple pulse breakup are found. These effects are ascribed to two-photon self-induced transparency analogous to that of a one-photon transition in a two-level system. A difference of input intensity between the two different frequency pulses yields curious modulation effects involving sharp peak amplification and marked pulse breakup for the low-intensity input. In contrast, the high-intensity input pulse displays a smooth variation with distance and time. Low-loss pulse transmission above threshold, and pulse advance and delay are found for the present case in contrast to that for one-photon self-induced transparency.
The effect of temporal coherent control on the two-photon-resonant third-harmonic generation and multiphoton ionization into the continuum states of an atomic system is experimentally and theoretically investigated by means of a pair of partially incoherent, identical laser pulses. The evidence of quantum interference as a function of the delay between the pulses is reported. The transition from the resonant to the nonresonant case is also shown. The obtained results agree with the prediction of a theoretical model showing that the onset of quantum interference appears to be related to the coherence time of the laser radiation, which is much shorter than the pulse duration.
The analysis of two-photon resonant third-harmonic generation is generalised to include, in particular, the effects of imperfect index matching and two-photon tuning. Furthermore, whereas previously the authors considered only the temporal properties of the generated harmonic signal, here is spectral characteristics are also considered. The authors comment on a discrepancy between the predictions of semiclassical and quantised field formalisms. In the semiclassical analysis, it is shown that for large energy input pulses the harmonic spectrum is double peaked even near exact resonance and that this structure can be interpreted in terms of transitions between sets of doublet states of the Autler-Townes (1955) type. In a quantised field formalism, however, the picture is radically altered near exact resonance where a three-peaked spectrum is predicted.