Journal of Physics B Atomic Molecular and Optical Physics
Interference betweenE2 andM1 amplitudes in two-colour frequency mixing in atoms
Vitalii D Ovsiannikov, Nikita V. Pershin, Evgueni V. Tchaplyguine
Abstract
The relative contributions of the magnetic dipole interaction ( M 1) and the electric quadrupole interaction ( E 2) in the dipole-forbidden three-wave process of mixing two-colour radiation in free atoms may be determined from the dependence of the frequency-conversion efficiency on the incident-wave polarization. Analytical expressions are derived for the polarization dependence of amplitudes and cross sections of a double-resonant scattering of the sum- and difference-frequency photons. Numerical estimates are presented for the ratio of E 2 and M 1 three-photon amplitudes in ground-state indium and thallium atoms.