Simple wavelength pre-selection and stabilization of the single-frequency operation of a microchip laser

Abstract

This paper presents the concept and experimental verification of a simple method of wavelength pre-selection of a single frequency, second-harmonic generation SHG solid state laser Nd:YAG/KTP with the Lyot filter. Apart from well-known configuration of single-frequency operation, the Lyot filter to stabilization of the wavelength was used. The idea presented is based on a measurement of the losses introduced by the Lyot filter inside the laser cavity, or the maximums of laser output power as a measure of the assessment of the Lyot filter tuning to a required laser longitudinal mode, not requiring any external frequency standards. This method allows for the synthesization and stabilization of a selected wavelength from the spectrum range of the gain curve of the laser with the period determined by the “Lyot comb”. In the developed system 15 values of wavelength spaced at about 32 pm (∼ 7.9 GHz) for the infrared radiation were obtained.