Optimisation of dual-wavelength Bragg mirrors

A numerical method for the optimisation of dual-wavelength Bragg mirrors is presented. It takes into account the dispersion of the refractive index, and can be applied to generate two highly separated stopbands. The method is tested in a configuration useful for doubly-resonant second harmonic generation (stopbands at /spl lambda/ and 2/spl lambda/), a situation for which simple analytical methods fail.