RESUMEN
A continuous-wave-operation laser amplifier chain consisting of three multi-concentration-doped Yb:YAG slab gain modules (GMs) at room temperature is presented. The output power of 22.3 kW with the beam quality of 3.3 times the diffraction limit is achieved from this chain. To the best of our knowledge, based on a Yb:YAG slab at room temperature, the highest power to date while maintaining excellent beam quality laser output. An extraction efficiency of 36% from the single slab GM is obtained and can be further enhanced to 46% by optimizing the parameters of GM. These results have confirmed that the Yb:YAG slab has an excellent scaling performance and is suitable for the development of high-average-power lasers.
RESUMEN
An average 9 kilowatt-level direct-D2O-cooled side-pumped Nd:YAG multi-disk laser resonator at QCW mode with a pulse width of 250µs is presented, in which the straight-through geometry is adopted the oscillating laser propagates through 40 Nd:YAG thin disks and multiple cooling D2O flow layers in the Brewster angle. Much attention has been paid on the design of the gain module, including an analysis of the loss of the laser resonator and the design of the Nd:YAG thin disk. Experimentally, laser output with the highest pulse energy of more than 20 J is obtained at a repetition frequency of 10 Hz. At high repetition frequency, the average output power 9.8 kW with ηo-o = 26% and 9.1 kW with ηo-o = 21.8% are achieved in the stable resonator and unstable resonator, respectively, and in the corresponding beam quality factor ßstable= 14.7 and ßunstable= 9.5 respectively. To the best of our knowledge, this is the first demonstration of a 9 kilowatt-level direct-liquid-cooled Nd:YAG thin disk laser resonator.
RESUMEN
We demonstrate a master oscillator power amplifier (MOPA) architecture based on Yb:YAG amplifiers and adaptive optics (AO) systems with a high power and high beam quality laser output. With two conduction cooled, dual-end-pumped Yb:YAG zigzag-slab amplifiers at room temperature, the fiber laser of 300 W was scaled to 11.9 kW. Moreover, AO system positioned downstream was utilized to correct wavefront of amplified laser. The beam quality ß at maximum output power was 2.8 times diffraction limited with closed-loop AO system.
RESUMEN
A direct-liquid-cooled side-pumped Nd:YAG multi-disk QCW laser resonator is presented, in which the oscillating laser propagates through multiple thin disks and cooling flow layers in Brewster angle. Twenty Nd:YAG thin disks side-pumped by LD arrays are directly cooled by flowing deuteroxide at the end surfaces. A laser output with the highest pulse energy of 17.04 J is obtained at the pulse width of 250 µs and repetition rate of 25 Hz, corresponding to an optical-optical efficiency of 34.1% and a slope efficiency of 44.5%. The maximum average output power of 7.48 kW is achieved at the repetition rate of 500 Hz. Due to thermal effects, the corresponding optical-optical efficiency decreases to 30%. Under the 12.5 kW pumping condition while not oscillating, the wavefront of a He-Ne probe passing through the gain module is as low as 0.256 µm (RMS) with the defocus and tetrafoil subtracted.
RESUMEN
A waveguide scheme is constructed by coating the matrix of randomly distributed ZnSe nanosheet structures with a layer of dye-doped polymer, which provides strong feedback or gain channels for the emission from the dye molecules and enables successful running of a random laser with FWHM of ~0.65 nm. The strong scattering by the nanostructures and the strong confinement provided by the active waveguide layer are the key essentials for the narrow-band and low-threshold operation of this random laser. The random laser scheme reveals an obvious two-threshold behavior, which is corresponding to the thresholds of TM and TE modes. The feedback mechanisms for laser action are investigated by power Fourier transforming of the spectra. This kind of active waveguide not only provides high quality confinement of the radiation for efficient amplification, but also enables possible directional output of this kind of random laser.