A compact, multichannel, phase-locked, carbon dioxide laser

The carbon dioxide laser has become an increasingly important tool in research and industry. Consequently, it has been desirable to produce more powerful, yet compact and efficient laser systems. Recently, two methods have emerged as forerunners in the achievement of this goal. These methods are: an extended-area electrode scaling approach, as applied to RF-excited, diffusion-cooled laser devices; and coherent phase-locking of multiple gain channels in an extended laser array.; The purpose of this investigation was to examine the feasibility of incorporating the above two concepts into a single device. Initial experiments demonstrated that a stable {dollar}alpha{dollar}-type gas discharge could indeed be simultaneously established within all the channels of a multichannel gain system. A subsequent analysis of the gain and saturation intensity parameters indicated that lasing operation was possible with this device.; An extensive series of optical extraction studies were performed employing several different resonator designs. These configurations included a conventional unstable resonator and a unique toric unstable resonator. Toric resonators were found to possess the advantages of a conventional resonator, plus the ability to extract the output beam from the centerline of the laser system. Furthermore, it was discovered that the size of the output coupling aperture in the toric systems had a profound influence on the output characteristics of the device. Parameters examined for each of the resonators included output power, near-field and far-field behaviour, alignment sensitivity and polarization properties.; The phase-locking characteristics of the system were also explored. Phase-locking levels as high as 91% were measured for the conventional resonator when an injection seed beam was fed into the central region of the resonator. With no injected beam, self-phase-locking levels as high as 62% were also determined between the individual channels. The mechanism for this locking was identified to be the independent lasing of the central inter-electrode region, plus the converging wave properties of the unstable resonators. These two attributes acted as the core oscillator region, which then supplied the surrounding gain channels with a common, fundamental optical mode.; Finally, laser cutting of mild steel was performed to document the usefulness of the device in a typical materials processing application. Cutting speeds comparable to currently available commercial systems were achieved, with the added benefit of the ability to cut at the same process speed, irrespective of the direction. This latter feature resulted from the unique polarization state of the output beam.