Three-photon resonantly enhanced multiphoton ionization and third-harmonic generation with unfocused laser beams

Journal Article · Fri Aug 01 04:00:00 EDT 1986 · Phys. Rev. A; (United States)

DOI:https://doi.org/10.1103/PhysRevA.34.1143· OSTI ID:5408174

Payne, M G; Garrett, W R; Ferrell, W R

Several extensions are made in theoretical studies of multiphoton ionization associated with third-harmonic fields that are generated near three-photon resonances in gaseous media. The treatment includes the strong coherent cancellation effect which occurs between three-photon pumping of a resonant level and pumping by the third-harmonic field that is generated in the same medium. The incomplete spoiling of the cancellation effect with counterpropagating beams is quantitatively described. Also, treatment of the multiphoton-ionization problem involving phase-matched, third-harmonic fields is generalized to include quantitative effects of index changes due to a buffer gas, absorption due to dimers, and collisional dephasing of coherent excitations. Finally, we show how measurements of linewidths, phase-matching positions, and pressure dependences of ionization yields associated with third-harmonic generation and subsequent absorption can be used to determine oscillator strengths of a resonant level, absorption coefficients for a resonant species and a buffer-gas species, and the refractive index of the buffer gas at the third-harmonic frequency.

• Research Organization: Chemical Physics Section, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 5408174
• Journal Information: Phys. Rev. A; (United States), Journal Name: Phys. Rev. A; (United States) Vol. 34:2; ISSN PLRAA
• Country of Publication: United States
• Language: English

Related Subjects

657005* -- Theoretical Physics-- Optics
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ELECTROMAGNETIC FIELDS
ELECTROMAGNETIC RADIATION
FLUIDS
FREQUENCY MIXING
GASES
HARMONIC GENERATION
IONIZATION
LASER RADIATION
MULTI-PHOTON PROCESSES
OPTICAL PROPERTIES
OPTICAL PUMPING
OSCILLATOR STRENGTHS
PHOTOIONIZATION
PHYSICAL PROPERTIES
PUMPING
RADIATIONS
REFRACTIVITY
RESONANCE