Excess-noise dependence on intra-cavity aperture shape

Summary form only given. Unstable-cavity lasers have attracted much attention because of the interesting properties of their eigenmodes including non-orthogonality and fractal character. Non-orthogonality has profound consequences for the quantum-limited laser linewidth /spl Delta//spl nu/ leading to its enhancement by the so-called excess noise factor K. This factor depends on the eigenmode field distribution, which in turn depends on cavity geometry. However, only lasers with square and circular intra-cavity apertures have previously been the subject of detailed investigation. The full extent to which 2D transverse geometry influences K has thus remained an open question. We report the first theoretical and experimental investigations of K-factors in lasers with truly 2D aperturing.