Abstract

It has recently been shown theoretically¹ that increasing both the loss and gain of a two-mode ring laser so as to maintain the working point leads to reduced backscattering effects, even though the absolute backscattering rate remains unchanged. In principle, the intensity cross correlation should change from positive to negative values, which it would have with zero or very low backscattering. By introducing a variable loss element in the form of a rotatable glass plate into the ring laser cavity, we have been able to confirm several of the theoretical predictions experimentally. In particular, we demonstrate the change from negative to positive intensity cross correlations as a knife-edge is progressively inserted into the laser beam.

© 1988 Optical Society of America