Theory of coherent two-photon absorption

Sunil Kumar

P. Lambropoulos, Chihiro Kikuchi, R. K. Osborn

A kinetic theory of the two-photon absorption from a single mode of the radiation field is presented. It is found that, in general, the rate of two-photon absorption depends on certain correlation functions, and hence on the coherence properties, of the field. The results are applied to the case of a pure coherent state and the case of a chaotic field.

Hiroshi Sekiya, Seikyo Tsunekawa, Kiyoshi Nishikawa +1 more

Masamoto Takatsuji

A theory of coherent two-photon resonance is developed by applying a canonical transformation on the Heisenberg equation of atomic motion. The theory leads both to the optical Bloch equation and the second-order induced polarization which drives the classical Maxwell's equation. The expressions for the Rabi frequency and the induced polarization are given explicitly for two-photon absorption and Raman effect. The results are applied to coherent steady-state propagation, and two kinds of pulses are derived for different-frequency two-photon absorption, including the atomic frequency shift.

清 西川, 昭 佐道, Hiroshi Sekiya +3 more

Gordon N. Sinclair, Xiaoyi Bao, Daniel S. Elliott +1 more

Measurements of two-photon absorption spectra have been made for the case where the exciting laser has a random-telegraph phase. The resulting spectral shapes are compared to theoretical predictions and to previous data taken with a phase-diffusing laser field [Elliott et al., Phys. Rev. A 32, 887 (1985)]. A striking dependence of the absorption spectrum on the second-order coherence of the field was observed. Using the theory for the propagation of second-order spatial coherence, we draw an analogy between diffraction and two-photon absorption which we use to interpret the two-photon absorption spectra.