Phase locking counterrotating modes of a broadband ring dye laser.

We present the results of an experimental study of phase locking counterrotating modes in a Rhodamine-6G continuous-wave broadband ring dye laser. Results for the measured mutual coherence of the counterrotating fields are presented for three different coupling geometries: namely, coupling by using an intracavity retroreflector, a single extracavity retroreflector placed in one of the output beams,and extracavity retroreflectors placed in each of the two output beams. We find that the highest degree of locking is obtained for the case of the intracavity retroreflector and leads to counterrotating outputswith a measured mutual coherence of unity.

Effects of laser coherence on coupling efficiency for the double phase-conjugate mirror.

We present the results of an experimental study of the effects of laser coherence on the operation of the double phase-conjugate mirror using barium titanate as the nonlinear medium. In our experiment the two input beams that drive the interaction originate from a single helium-neon laser, and the degree of coherence between the input beams at the crystal is varied through the use of a time-dependent phase delay in one of the beam paths. As the two input beams make the transition from being mutually incoherent to mutually coherent, the phase-conjugate reflectivity decreases dramatically and becomes unstable. These results are significant to laser phase-locking applications where changes in the coupling intensity can affect the quality of phase locking.