Unstable resonators with polygon and von Koch-type boundary conditions : virtual source modelling of fractal eigenmodes

We will report on our latest research into modelling fractal lasers (linear systems that involve geometrically-unstable resonators with inherent magnification), and propose two new classes of cavity configuration. These devices are of fundamental theoretical interest as table-top generators of tunable fractal light that can be used in a wide range of applications. Moreover, we expect them to play a pivotal role in new Nature-inspired optical architectures and designs. The virtual source theory of classic kaleidoscope lasers will be reviewed, and we show how that semi-analytical method can be applied to novel cavity designs which incorporate a feedback mirror whose outer boundary corresponds to iterations of the von Koch snowflake (an iterated function system involving self-similar sequences of equilateral triangles) and its isosceles counterpart, the von Koch pentaflake . A range of new numerical results will be given, including calculations of mode patterns, eigenvalue spectra, and detailed computations of fractal dimension measures.