DEPENDENCE OF STIMULATED-BRILLOUIN-SCATTERING PHASE-CONJUGATION CORRECTION ON THE FAR-FIELD INTENSITY DISTRIBUTION OF THE PUMP LIGHT

Phase-conjugation correction by stimulated Brillouin scattering (SBS) was investigated experimentally as a function of bandwidth, polarization state, and far-field characteristics of the incident pump beam. The generation of standing waves in a nonabsorbing medium provided a sinusoidal phase aberration that was continuously tuneable in its amplitude and spatial frequency. A systematic study of conjugation fidelity was performed as a function of the number and the spacing of lobes in the far-field intensity distribution of the pump beam. It was found that correction of the aberration degraded when the lobe spacing was greater than approximately 2.5 Airy diameters. Phase conjugation of pump beams aberrated by Seidel aberrations was also tested. Excellent correction, even at low pump powers, was measured.