L. Lorini et al., ACCURATE GAS DIAGNOSTICS FOR SEALED-OFF CO2-LASERS USING NEAR-INFRARED DFB SEMICONDUCTOR-LASERS, IEEE journal of quantum electronics, 34(6), 1998, pp. 949-954
The selective spectroscopic detection of CO2 and H2O in the gas mixtur
e of a 400-W sealed-off CO2 slab laser is reported. The detection is b
ased on the acquisition of absorption Voigt profiles of two vibrationa
l overtone transitions of CO2 and H2O, obtained using two InGaAsP dist
ributed feedback (DFB) semiconductor lasers, This spectroscopic method
enables a direct absolute measurement of the temporal evolution for t
he concentrations inside the laser active volume. Monitoring takes pla
ce during laser operation without gas extraction. The experiments carr
ied out on CO2 and H2O abundances confirm the paramount importance of
wall desorbance phenomena in all-metal radio frequency (RF) excited la
sers.