Langmuir flow effects in the laser gyro

Langmuir flow effects have been investigated in the laser gyro by measuring the integral of the beat frequency while tuning the frequency of oscillation. The results are in agreement with the traveling-wave Lamb model. The presence of the dc discharge tube walls gives rise to gas circulation in the laser gyro cavity. If the oppositely directed traveling waves see a net gas flow the gyro exhibits a null shift which depends on the magnitude and direction of the discharge current unbalance causing the net gas flow. The null shift is shown to be due to the mode pulling and pushing associated with the anomalous dispersion exhibited by the gain atoms.