Coherent two-photon interactions with atomic sodium vapor

Thesis/Dissertation · Mon Jan 01 04:00:00 EST 1979

OSTI ID:5978536

Sutherland, R L

Two-photon interactions in atomic sodium vapor are considered both theoretically and experimentally. Since the frequencies of the radiation fields which are incident on the sodium are tunable, both resonant and nonresonant behaviors are described. To describe the nonresonant behavior in sodium quantum mechanical perturbation theory using the density matrix formalism is employed, and a macroscopic electric polarization which oscillates at the sum-frequency of the two incident fields is derived. This polarization is the source of radiation at the sum-frequency, and calculations predict that the intensity of this radiation will vary as the square of the sodium vapor density and linearly with the input intensities. Also, implicit in the expression for this intensity are resonant frequency and field polarization dependencies. Finally, the condition for noncollinear phase-matching whereby the sum-frequency intensity can be efficiently generated is described. An experiment to test the above predictions is described in which two dye lasers are incident on sodium vapor contained in a heat-pipe oven. The results agree quite well with the theory. In particular, the sum-frequency intensity varied quadratically with sodium density and linearly with input intensities. Also, the generated intensity was a maximum when the sum of the two laser frequencies coincided with the frequency of the 4d/sup 2/D/sub 3/2/-3s/sup 2/S/sub 1/2/ quadrupole transition. The relationship between the sum-frequency field polarization and the polarizations of the input fields through the nonlinear susceptibility was also verified.

• Research Organization: Ohio State Univ., Columbus (USA)
• OSTI ID: 5978536
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
ALKALI METALS
ATOM COLLISIONS
COHERENT RADIATION
COHERENT SCATTERING
COLLISIONS
DENSITY MATRIX
DYE LASERS
ELECTROMAGNETIC RADIATION
ELEMENTS
FLUIDS
GASES
LASERS
LIQUID LASERS
MATRICES
METALS
PERTURBATION THEORY
PHOTON COLLISIONS
PHOTON-ATOM COLLISIONS
POLARIZATION
RADIATIONS
SCATTERING
SODIUM
VAPORS