Diagnostics of a capillary discharge of a CO2 waveguide laser by coherent anti-Stokes Raman spectroscopy

Experimental results are reported from coherent anti-Stokes Raman spectroscopy (CARS) diagnostic studies of capillary discharge in the CO2:N2:He = 1:1:8 working mixture of a CO2 waveguide laser. The CARS scans were used to characterize the translational temperature of the gas and the vibrational temperatures of the discharge plasma components. The data are vital for identifying anharmonic states which reduce the laser power and working mixture lifetime. Data are furnished on the translational temperature and vibrational temperature as functions of the capillary radius. CARS is concluded to be a valid technique for studying the distribution of pump power among the degrees of freedom of the working mixture components, even when dissociation is occurring.