Abstract

Generation of visible light by second-harmonic generation (SHG) of diode laser radiation using enhancement cavities with a nonlinear crystal is a well established technique. The main problem is to lock the laser emission to the resonance frequency of the enhancement cavity or vice versa. The two common approaches are electronic or optical locking. In electronic locking, an error signal proportional to the frequency detuning is generated [1]. This signal can be applied, e. g., to the driving current of the diode laser or to a piezo-controlled mirror. In optical locking, light is injected into the laser to force the laser emission to the resonance frequency of the enhancement cavity. Therefore, the enhancement cavity itself can be used to filter out the appropriate frequency [2].

© 2011 Optical Society of America