Second-order sum- and difference-frequency generation via quadrupole transitions in atomic vapors

Conference · Thu Sep 01 04:00:00 EDT 1977

OSTI ID:7077183

Bethune, D; Smith, R W; Shen, Y R

The inclusion of higher-multipole terms in the interaction of light with matter allows second-order nonlinear processes to be observed in isotropic media. These processes may be useful for both generating new wavelengths of radiation and measuring atomic or molecular quadrupole transition moments otherwise hard to determine. After a brief theoretical introduction, the experimental arrangement used to observe quadrupole sum-frequency generation is shown. Generally, the characteristics of the observed output agree with those predicted: the output shows the sharp two-photon resonance expected from the expression for chi/sup (Q)/ and the expected variation with k vector mismatch. At high densities and input powers, deviations from the simple theory occur: output falls sharply because of absorption associated with D-line resonances, two-photon saturation occurs, and third-order nonlinearities and population redistribution can cause changes in the index of refraction of the vapor which defocus the pump beams and destroy the phase matching of the output radiation. Quadrupole sum-frequency generation allows a novel and accurate measurement of quadrupole transition moments; values were found for the 3s-4d transition moment of Na. The creation of an electric dipole polarization by mixing of two pump fields, one of which is coupled to a quadrupole transition, can be described by the difference frequency polarization; chi/sup (Q/sub 1/)/ = 2.1 x 10/sup -12/ esu was found for Cs. 8 figs. (RWR)

• Research Organization: California Univ., Berkeley (USA). Lawrence Berkeley Lab.
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 7077183
• Report Number(s): LBL-6918; CONF-770645-2
• Country of Publication: United States
• Language: English

Related Subjects

640302* -- Atomic
Molecular & Chemical Physics-- Atomic & Molecular Properties & Theory
657005 -- Theoretical Physics-- Optics
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
74 ATOMIC AND MOLECULAR PHYSICS
ALKALI METALS
CESIUM
ELECTROMAGNETIC RADIATION
ELEMENTS
ENERGY-LEVEL TRANSITIONS
FLUIDS
GASES
INTERACTIONS
MATTER
METALS
NONLINEAR PROBLEMS
OPTICS
RADIATIONS
SODIUM
VISIBLE RADIATION