BLUE LIGHT GENERATION BY FREQUENCY DOUBLING A DIODE LASER

In this dissertation, we present a simple scheme for construction of a low noise continuous wave blue light source by frequency doubling a Fabry-Perot diode laser in a potassium niobate crystal inside a bow tie ring cavity. By feeding back the ring cavity transmission into the diode laser after reflection off a grating, the diode laser operates in single mode and is frequency locked to the cavity resonance. Using a simple analytic form of the beam parameters for the ring cavity, the optimum cavity configuration is found for a high degree of mode matching between the diode laser output beam and the ring cavity. The wavelength of the blue output is tunable from 484-488nm, has a narrow linewidth of 1.25MHz, and has a continuous tuning range of more than 10GHz. The output power of the blue light is 18mW with intensity fluctuations less than 0.02dB. The blue light is a near diffraction limited Gaussian TEM00 mode with M2 ≈ Numerical simulation of the SHG is carried out by using the Fourier space method, and the experimental results are in good agreement with the simulation