Automation of CO_2 laser output power measurement as a function of the absorber gas pressure in a cell located inside or outside the laser cavity

摘要

The automation of CO_2 laser output power measurement is discussed in this paper as a function of the absorber gas pressure in a cell located inside or outside the laser cavity. A manually tunable laser was used which can be operated in one of about 44 different laser lines aligned by the user and registered respectively by the acquisition program for further analysis. The voltages representing the absorber gas pressure and the output power were very small (a few hundred μV), therefore a proper voltage amplification circuit was designed to amplify the analog outputs of both the pressure meter and the laser output power meter. These amplified signals were then applied directly to a PCI-9112 ADLINK data acquisition card using a personal computer (PC). A suitable controlling program using LabVIEW graphical programming language was written to measure the pressure and laser power signals, draw the relationship between them and save the results for later processing and analysis; such as, gas absorbance coefficient α, mean absorption cross section σ calculations that can be applied in many areas such as molecular spectroscopy and environmental pollution studies.