Degenerative wave mixing in photorefractive (PR) crystals is suitable for the elimination of wavefront distortions and for beam cleaning; however, traditional schemes are restricted to monochromatic light sources of macroscopic coherence length. We report on experimental results which demonstrate that our novel disperse arrangement is well suited to PR phase conjugation of broadband radiation emitted by cw and femtosecond lasers. The efficiency of the wave mixing process depends on the contrast and length of the index grating produced in the PR crystal. In order to improve the efficiency we disperse the broadband laser beam perpendicular to the plane of propagation by a diffraction grating. The different spectral components appear spatially decomposed in the focal plane of a cylindrical lens, where the PR crystal is placed. We review our results in the cw regime and, for the first time, we report on experiments with femtosecond pulses, too. The PR crystal was an undoped BaTiO3 used in "CAT" self-pumped phase conjugation configuration. The light sources were Ti-sapphire lasers. The performance of the novel scheme was investigated in different conditions, and we observed efficient PC up to tens of nanometers of spectral bandwidth.
|Number of pages||5|
|Publication status||Published - Mar 1 2000|
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- Condensed Matter Physics
- Industrial and Manufacturing Engineering