Abstract

We have used a novel method to measure the fidelity of a stimulated Brillouin scattering phase conjugator. A 40-μm period phase grating splits a 532-nm beam into multiple orders. The conjugator returns the beams to the grating where they are recombined. The output energy in each of the grating orders allows us to infer the accuracy of the conjugation process. In preliminary experiments we blocked all but two incident orders and used a computer-based data logging system to measure the energies in four orders returned through the grating. The energies in two of these orders determine the relative gains seen by the incident beams while the energies in the other two orders essentially measure coherent addition and subtraction of the two beams returned from the conjugator. We have found that the energies measured in the latter two orders are inconsistent with perfect conjugation of both incident beams. The discrepancies can be attributed to the finite frequency shift of the Stokes beam and to the incomplete spatial reproduction of the returned orders.

© 1986 Optical Society of America