High Efficiency and High Stability for SHG in an Nd:YVO4 Laser with a KTP Intracavity and Q-Switching through Harmonic Modulation

In this paper, the stabilization and high efficiency of an unstable Second Harmonic Generation (SHG) of an Nd:YVO4 laser with a KTP intracavity is demonstrated. By using a passive Q-switching crystal (Cr4+:YAG) and a parametric modulation method (harmonic modulation), the stabilization of the laser is reached. An harmonic modulation was applied to the pumping of the Nd:YVO4-KTP laser to control the amplitude and frequency of the laser emission. The results were characterized by using power spectra analysis, optical spectrum, bifurcation diagrams, and temporal series of the laser intensity. The promising application of this green light source is materialized when such light is necessary for high-density optics, such as in the treatment materials industry or in some aesthetic applications.