Self-frequency tuning in birefringent K5Nd(MoO4)4 laser crystal

Abstract In this paper we report an experimental demonstration of broadband wavelength self-tuning in K5Nd(MoO4)4 laser crystal (KNM) together with a theoretical treatment of the system based on its birefringence properties. The self-frequency tuning in KNM was obtained by inserting an a-cut plate inside the resonator at Brewster’s angle. At a given position of the crystal plate, when the wavelength of the oscillating mode corresponds to an integral number of full-wave retardation in the plate, the laser operates in the p polarization of the Brewster surface with no losses. The experimental self-frequency tuning of the laser emission along the free spectral range of the KNM crystal was obtained by rotating the birefringent gain plate in its own plane. To investigate the tuning characteristics of the spectral filter, we have used the Jones-vector formalism. The calculated wavelength-selective tuning matches very precisely the experimental observations. As far as we know this is the first time the grounds and operation of such a device is demonstrated.