Alternating dual-wavelength second harmonic generation at 532 nm using a Y-branch distributed Bragg reflector diode laser

Alternating dual-wavelength second harmonic generation at 532 nm using a 1064 nm Y-branch distributed Bragg reflector diode laser will be presented. The light source is based on single-pass frequency conversion in a periodically poled lithium niobate waveguide crystal with superimposed poling periods. All components, including the diode laser, optics for beam shaping and the nonlinear crystal, are mounted on a 5 x 25 mm(2) aluminum nitride micro-optical bench soldered on a 25 x 25 mm(2) conduction cooled package mount. Separated electrical contacts for the diode laser allow for alternating, wavelength stabilized dual-wavelength laser emission with spectral widths of 0.02 nm (0.2 cm(-1)). Heater elements implemented above the DBR gratings enable wavelength tuning, which is utilized for phase-matching at both wavelengths. At a heat sink temperature of 25 degrees C, optical output powers of 5.6 mW at 532.45 nm and 6.7 mW at 531.85 nm with a spectral width of 0.01 nm (0.35 cm(-1)) are obtained. The developed light source is suitable for demanding applications such as Raman spectroscopy and shifted excitation Raman difference spectroscopy.