Beam deflection in a transverse-flow gas laser

The beam deflection phenomenon of a transverse-flow discharge-excited CO/sub 2/ gas laser is studied by measuring the beam pattern with the rotating-wire method at gas velocities of 35-70 m/s, gas pressures of 5.3-10.6 kPa (10/sup 3/ N/m/sup 2/), and laser powers of 50-700 W. The beam deflection distance increased with increasing laser power and gas pressure and with decreasing gas velocity. All the data points of beam deflection distances observed experimentally fell on one line when normalized by the gas pressure and plotted against the measured temperature gradient in the resonator. It is shown that the most important factor affecting the beam deflection is the refractive index variation of the gas produced by the gas temperature gradient in the resonator. Methods to reduce the beam-deflection distances are suggested.<>