Method for calculating a negative-dispersion resonator-type multilayer mirror

A method is proposed for the calculation of negative-dispersion mirrors with resonator cavities. The mirror optimisation algorithm combines the capabilities of the gradient method and the random search method. A multilayer mirror structure with a reflectivity R>99.9% and a group delay dispersion of -60 ± 10 fs² in the 930–1070 nm wavelength range was calculated. The sensitivity of the obtained structure to random variations of layer thicknesses was analysed.