High peak power, sub-ps green emission in a passively mode locked W-cavity VECSEL.

We report on the experimental results of a passively mode-locked vertical external cavity surface emitting laser (VECSEL), implemented in a W-cavity configuration, using a lithium triborate (LBO) crystal for intra-cavity second harmonic generation (SHG) at 528 nm. The W-cavity configuration allows separation of the crystal from the semiconductor saturable absorber mirror (SESAM), enabling independent control over the Gaussian beam sizes at the crystal, chip, and SESAM. This optimized cavity demonstrated a second harmonic pulse width of ~760 fs at a frequency of 465 MHz and 230 mW average output power, resulting in a peak pulse power of 580 W.

Generation of high-power spatially structured beams using vertical external cavity surface emitting lasers.

In this paper, we demonstrate the generation of high-power and spatially structured beams using vertical external cavity surface emitting lasers (VECSEL). At the fundamental wavelength, an intracavity mode-control element is first employed to generate a range of Hermite-Gaussian (HG) modes in a linear cavity. The same HG modes are then excited and frequency doubled in a V-cavity geometry to generate a rich variety of high-power spatially structured beams. The results compare well with our numerical modeling.

Tunable type II intracavity difference frequency generation at 5.4 µm in a two chip vertical external cavity surface emitting laser.

We report on the generation and experimental demonstration of intracavity type II difference frequency generation in a two chip InGaAs/GaAs vertical external cavity surface emitting laser. The presented two chip cavity provides two orthogonally polarized, independently tunable, high-intensity lasing modes with emissions around 970 and 1170 nm. A silver thiogallate nonlinear crystal is inserted in the common collinear folded region of the cavity to generate output in the mid-IR spectral band. The independent tunability of each fundamental color allows for more than 100 nm of tuning around a 5.4 µm difference frequency generated signal with a CW output power in excess of 5 mW.

Tunable type II intracavity sum-frequency generation in a two chip collinear vertical external cavity surface emitting laser.

We report on the generation and experimental demonstration of intracavity type II sum-frequency generation (SFG) in a two chip InGaAs/GaAs vertical external cavity surface emitting laser cavity. The demonstrated two-chip cavity generates two orthogonally polarized, independently tunable, high-intensity intracavity lasing modes at different colors. Using a lithium triborate nonlinear crystal in the common collinear folded cavity region, high output power in the blue-green band is generated. Wavelength tuning with CW output powers in excess of 750 mW is demonstrated. By independent wavelength tuning of each fundamental color, tunable SFG output around 490 nm is reported.

Gain coupling of class A semiconductor lasers.

We report on the development of a gain-coupled class A semiconductor laser for dual-wavelength generation via optical switching. A vertical external cavity surface emitting laser (VECSEL) structure is used, because it provides a flexible platform for high-power, high-brightness output in the near-IR and visible ranges. For the first time (to our knowledge), two VECSEL cavities sharing a common gain region are studied. Because the cavities are in competition for common carriers, birefringent filters in the external cavity control the laser cavity thresholds; this configuration demonstrates the possibility of switching between the two cavities, which can operate at different wavelengths. However, in this Letter we also show, numerically and experimentally, that with the consideration of spontaneous emission, it is possible to maintain simultaneous lasing in each cavity at a different wavelength.

Continuous-wave all-solid-state 244 nm deep-ultraviolet laser source by fourth-harmonic generation of an optically pumped semiconductor laser using CsLiB6O10 in an external resonator.

We report an all-solid-state laser system that generates over 200 mW cw at 244 nm. An optically pumped semiconductor laser is internally frequency doubled to 488 nm. The 488 nm output is coupled to an external resonator, where it is converted to 244 nm using a CsLiB(6)O(10) (CLBO) crystal. The output power is limited by the available power at 488 nm, and no noticeable degradation in output power was observed over a period of several hours.