Reducing the effects of backscattering on the behavior of a ring laser.

Light scattered from one counterpropagating mode into the other can drastically modify the behavior of a ring laser. We point out that, within the domain of the third-order laser theory, the effect of backscattering on the fluctuation properties of the light can be reduced simply by increasing the cavity-loss rate, so long as the increased loss can be compensated for by increased pumping of the gain medium.

Optical data storage readout with quadrant pupil detection.

A novel detection scheme that uses combinations of quadrant signals derived in a pupil of the optical system is described for optical storage devices. The signals arise because of an asymmetry in the reflected light distribution when the focused spot scans data with a nonzero tracking offset. Theoretical and scalar diffraction characterization indicates that the signals may be useful for improved data density by reducing intertrack interference (cross talk). The signals may also be useful for providing a tracking error signal.

Chaos in a good-cavity single-mode dye laser due to turbulent dye flow.

Experimental results are presented that demonstrate that the light intensity of a good-cavity single-mode standing-wave dye laser can exhibit chaotic behavior. The governing attractor is of dimensionality 6.5 and entropy 50 kbits/sec. An examination of the pump-laser beam before and after its interaction with the dye indicates that the chaos is probably due to the turbulent flow of dye within the dye cell. This interpretation is confirmed by the absence of chaos in two similar dye lasers that use a dye jet rather than a dye cell.