Four-Wave Mixing and Propagation of Laser Beam through Atomic Vapor

A. A. Preobrazhenskaya, Д. Ю. Преображенский, A. A. Pastor +1 more

In this paper, we investigated the coherent degenerate and nondegenerate four-wave interaction in the propagation of a femtosecond laser pulse in atomic rubidium vapor. In the case of degenerate four-wave interaction, the mechanism for optical switching in an optically dense resonant medium is considered. The third-order nonlinear interaction of the laser beams intersecting in the cell at a small angle leads to a nonlinear response in the form of a fourth beam, which occurs as a result of the interaction between the two pump beams and the third signal laser beam.

Y.-W. Chen, Chiyoe Yamanaka, Hideaki Niki +3 more

Xuewen Wang, Jinpeng Yuan, Lirong Wang +2 more

Abstract We demonstrate 1.37 µ m coherent near-infrared light generation via self-seeded parametric four-wave mixing (FWM) process in Rb atomic vapor. Two lasers (780 nm and 776 nm) in the co-propagating configuration, drive the Rb atoms from the 5S 1/2 ground state to the 5D 5/2 excited state. The parametric FWM around the 5P 3/2 –5D 5/2 –6P 3/2 –6S 1/2 –5P 3/2 transition loop is effectively established under phase matching conditions. The generated coherent light wavelength is confirmed using an optical spectrum analyzer, and the output power is investigated with the input laser frequency, power and atomic density. Consequently, a 1.37 µ m coherent light with the power of 27 µ W and the beam quality of M x 2 = 1.22 and M y 2 = 1.25 is obtained. An additional 795 nm laser is introduced to enhance the output power by 1.5 times through velocity-selective optical hyperfine repumping.

James J. Wynne, P. P. Sorokin

Hao Liu, Jinpeng Yuan, Lirong Wang +2 more

We demonstrate the generation of the coherent 420 nm laser via parametric four-wave mixing process in Rb vapor. A single 778 nm laser with circular polarization is directly injected into a high-density atomic vapor, which drives the atoms from the 5S1/2 state to the 5D5/2 state with monochromatic two-photon transition. The frequency up-conversion laser is generated by the parametric four-wave mixing process under the phase matching condition. This coherent laser is firstly certified by the knife-edge method and a narrow range grating spectrometer. Then the generated laser power is investigated in terms of the power and frequency of the incoming beam as well as the density of the atoms. Finally, a 420 nm coherent laser with power of 19 μW and beam quality of M x 2 = 1.32 , M y 2 = 1.37 is obtained with optimal experimental parameters. This novel laser shows potential prospects in the measurement of material properties, information storage, and underwater optical communication.

W. Happer, A. C. Tam