Laser diode injected intracavity-doubled Ti : sapphire laser for single-mode tunable UV sources

Intracavity frequency doubling of a pulsed Ti:sapphire laser is shown to be well described by multimode rate equations nonlinearly coupled through the homogeneous gain linewidth of the amplifying medium. Hole burning in the f undamental wave spectrum is observed at the phase-matched frequency and is explained well by theory in terms of the dynamic depletion of the fundament al waves phase-matched to the nonlinear output mirror. The doubling convers ion efficiency is shown to be greatly improved by injection seeding at the same frequency as the "spectral hole" with a low pow er continuous-wave-tun able laser diode. This leads, for the first time to our knowledge, to singl e-mode UV-tunable (380-410 nm) emission using this technique. Finally, the source is shown to exhibit a minimum yield at the coincidence between injec tion and exactly phase-matched wavelengths while maintaining high efficienc y when injecting a fen nanometers away from the phase-matching maximum.