Multiwaveguide CO2 laser with diffractive coupled channels

The constructions of high power RF excited waveguide lasers based on multichannel arrays usually require investigations of the cross-coupling between the laser beams in the array. 1,2 We built two structures of a ten-channel RF excited CO 2 waveguide laser array. Each laser was 400 mm long (380 mm of active length) with the cross-section of 2.2 × 2.2 mm of an individual channel and 0.5 mm thick sidewalls. The first structure was an uncoupled array whereas the second one was diffractive coupled. The maximum output power of the uncoupled array was 250 W at the pressure of 105 Torr. We applied a simple and useful optical arrangement with an external diffraction grating (153 lines/mm) for the simultaneous observation of an array laser spectrum. The laser beams spread on the grating were observed as a dot matrix at a phosphor image screen in a re-imaged near field. Manual and 2-D PZT mirror tuning and tilting enabled us to align all laser beams into the same matrix row corresponding to the separate spectral line. The lasers in the array operated at the few strongest P- or R-branch transitions of the 10.4µm band. A pattern of the transitions was easily identified by above arrangement.