Efficient directly emitting high-power Tb3+:LiLuF4 laser operating at 587.5 nm in the yellow range.

We present, to the best of our knowledge, the most efficient solid-state laser directly emitting in the yellow spectral range. Without any nonlinear conversion steps, a Tb3+:LiLuF4 laser operates at a wavelength of 587.5 nm with an output power of 0.5 W and a record-high slope efficiency of 25% with respect to the absorbed pump power at 486.2 nm. Despite the detrimental influence of 4f-excited state absorption, this efficiency is comparable to those obtained by complex nonlinear methods to generate yellow laser emission. Our approach, in combination with the progress in laser diodes at the required pump wavelength, paves the way for the development of cost-efficient, robust, and easily manageable diode-pumped yellow laser sources.

Deep red diode-pumped Pr³âº:KY3F10 continuous-wave laser.

We report the first observation of continuous-wave laser emission at 720 nm, in the deep red region, of a Pr3+:KY3F10 (Pr:KYF) single crystal, pumped with a blue InGaN-based laser diode at 446 nm. We employed a hemispherical cavity with three different output coupling mirrors transmitting 0.7%, 1.4%, and 2.7% of laser radiation. We obtained a maximum output power of 207 mW with a slope efficiency of 24.3%, comparable for the first time to what has been reported for other praseodymium-doped fluoride crystals. The round-trip cavity losses for our sample were estimated to be between 0.3% and 0.6%, a remarkably small value for this material.

Highly efficient continuous wave blue second-harmonic generation in fs-laser written periodically poled Rb:KTiOPO4 waveguides.

Waveguides were inscribed into a 9.5 mm long periodically poled KTiOPO4 crystal with a Ti:sapphire femtosecond-laser. Waveguiding was achieved between two parallel written tracks with spacings of 17-19 µm. The fundamental power of 1.6 W for frequency doubling in the waveguide was delivered by a continuous wave Ti:sapphire laser at a wavelength of 943.18 nm. A maximum output power of 76 mW in the blue spectral region was achieved. This corresponds to a single pass normalized conversion efficiency of 4.6% W(-1) cm(-2).

Wide wavelength tunability and green laser operation of diode-pumped Pr3+:KY3F10.

We report on wide spectral tunability of a quasi-continuous wave Pr(3+):KY(3)F(10) laser under InGaN laser diode excitation at 445 nm. The total tuning range exceeded 100 nm in the visible spectral range on several intervals between 521 nm and 737 nm. The broadest continuously tunable region of almost 50 nm extended from 688 nm to 737 nm. Furthermore we present what is to the best of our knowledge the first demonstration of continuous wave laser operation in Pr(3+):KY(3)F(10) on three transitions in the green spectral region. The highest output power of 121 mW was achieved at an emission wavelength of 554 nm with a slope efficiency of 27%.