A GENERALIZED DIFFRACTION FILTERED RESONATOR WITH A COPPER VAPOR LASER

The diffraction filtered resonator (DFR) offers large volume utilization while maintaining the diffraction limited nature of the output. Large active volume utilization demands a DFR with large resonator length and/or very small pinhole diameter. Increase in the resonator length results in lesser number of transits through the gain medium. Reducing the diameter of the pinhole, on the other hand, would reduce the feedback and hence increase the amplified spontaneous emission. In this paper a generalized DFR scheme is proposed, in which the mode volume is increased without either increasing the resonator length or reducing the pinhole diameter. The performance of these resonators with a high-gain, self-terminating laser like copper vapor laser is studied and compared with an equivalent semiconfocal DFR.