Lifetime Effects in Phase Conjugation via Degenerate Four-Wave Mixing.

V. V. Kabanov, Alexander S. Rubanov, Alexei L. Tolstik +1 more

Aleksander Błȩdowski, Adam Kujawski

Fan Rong-Wei, Deying Chen, Fang Tao +3 more

In this paper, frequency-doubled Nd:YAG laser's phase conjugation has been investigated experimentally using resonant degenerate four-wave mixing (DFWM). The iodine solution was used as resonant medium. In this way, the energy of the DFWM phase conjugation beam arrived at 43μJ/pulse while the total pump beam's energy reached 8mJ/pulse. The relation between the pulse energy of the DFWM phase conjugation beam and that of the pump beam was investigated. We also measured the optical field distributions of pump beam and DFWM phase conjugation beam, from which it can be noticed that the DFWM phase conjugation can improve the laser beam quality. At the same time, we observed the influence of the pump beam's disturbance on the DFWM signal.

A.C. Cefalas, S. M. Spyrou, Cleanthis A. Nicolaides

Phase conjugated waves via degenerate four wave mixing with picosecond laser pulses having a full width at half maximum (FWHM) of 80 ps have been observed in alcali vapours. The dephasing time of the 2P3/2 state in sodium was found to be 7.4 ns. This is the lifetime of the transient volume grating of the atomic states which are involved in the phase conjugated experiment. The average time of the perturbation of the atomic wave functions due to a "hot" collision (from a frequency modulation of a Markov type) was found to be 5x10-14 sec.

Henk F. Arnoldus, Thomas F. George

William M. Grossman, David M. Shemwell

The effect of coherence between pump and signal beams on phase conjugation by degenerate four-wave mixing is analyzed using a simple classical model. The influence this may have on practical applications is discussed.