Abstract

Recently, we used¹ a modified Fabry-Perot (MFP) interferometer to reduce the bandwidth of CO2 lasers operating at t atm and at 10 atm to a single longitudinal mode. The MFP consisted of two highly reflecting metallic mirrors and a beam splitter of low reflectivity, such as an uncoated NaCl window. Such an MFP has two main advantages: first, it can withstand high internal powers; second, its frequency selectivity is very high since the MFP finesse increases as the beam-splitter reflectivity decreases. In our experiment, a grating or an étalon were used¹ to line tune the CO₂ lasers, white the MFP served for fine tuning within the line.

© 1986 Optical Society of America