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Laser-diode (LD) pumped self-frequency doubling (SFD) Nd:GdCa4O(BO3)3 (Nd:GdCOB) miniature laser was demonstrated. The output power as high as 1.35 W was achieved which is over than five times than previous values for Nd:LnCa4O(BO3)3 (Ln=Y or Gd) SFD lasers and becomes the highest continuous-wave output power in this field to our knowledge. The maximum optical conversion efficiency is 17%. By comparison, we found that the cutting direction along its optimal phase-matching direction out of the principal planes is the determining factor resulting in this watt-level efficient output power. Different with previous studies, the emission wavelength is centered at about 545 nm. We believed that this efficient laser will become the most competitive one in the existing commercial green lasers, especially in the laser display, medical treatment and spectroscopic analysis etc.

A nanosecond 1.3 microm Nd:YAG laser-pumped external cavity eye-safe Raman laser based on BaWO(4) crystal is efficiently demonstrated. The average power of 1.5 microm was 0.60 W operating at a pulse repetition rate of 1.7 kHz and an incident pump power of 4.14 W. Conversion efficiency of 14.5% and a high slope efficiency of 54.5% have been achieved. Pulse shortening was obviously observed. The pulse duration of the first Stokes was about 40 ns, much shorter than the fundamental pulse with a duration of approximately 220 ns.

Temperature-dependent thermal and spectroscopic properties of Nd:YVO4 crystal at temperatures ranging from 77 to 300 K are presented. Thermal properties including specific heat, thermal expansion coefficient, and thermal conductivity are investigated. The spectroscopic parameters, such as absorption, fluorescence, lifetime are also studied. The calculated absorption and emission cross-sections together with relevant thermal properties provide important information for designing cryogenically cooled near infrared laser. Furthermore, we experimentally explore continuous wave (CW) laser performances under various cryogenic temperatures. A maximum output power of 2.13 W is obtained at an incident pump power of 3.7 W at 150 K, corresponding to an optical-to-optical conversion efficiency of 57.6%. [ABSTRACT FROM AUTHOR]

Ways on energy enhancement for single frequency oscillator are reported in this paper. By quantitative analysis on gain and loss coefficients for each cavity mode with inserted etalons, a 37 mJ, 100 Hz high energy single-frequency Nd:YAG oscillator is obtained. The pulse energy is promoted by enhancement of nearly 7 times for a single frequency oscillator reported. The result proves that this method does help for energy enhancement. It has attractive potential for high energy single frequency oscillator design, especially on condition of intensive side pumped or long cavity laser, where strong competitors exist and are hard to be suppressed. [ABSTRACT FROM AUTHOR]

We report on a high-power continuous-wave (CW) intracavity frequency-doubled laser at 670.8 nm, which is produced by the second-harmonic generation of a diode side-pumped Nd:YAP crystal laser with a type-II noncritically phase-matched LBO crystal. A maximum output power up to 13 W at 670.8 nm is obtained with an optical-to-optical (808 nm → 671 nm) efficiency of 2.4%. The beam quality factor M2 is measured to be 8.85, and the fluctuation (RMS) of output power is < ± 0.6% over 30 min. To the best of our knowledge, this is the highest power for the CW laser at 670.8 nm. [ABSTRACT FROM AUTHOR]

The multiwavelength characteristics of stimulated Raman scattering (SRS) in YVO4crystal excited by a picosecond laser at 1064nm are investigated theoretically and experimentally. Laser output with seven wavelengths is achieved coaxially and synchronously at 894, 972, 1175, 1312, 1486, 1713 and 2022nm in a YVO4crystal. The maximum total Raman output energy is as high as 2.77 mJ under the pump energy of 7.75 mJ. A maximum total Raman conversion efficiency of 47.8% is obtained when the pump energy is 6.54 mJ. This is the highest order of Stokes components and the highest output energy generated by YVO4reported up to date. This work expands the Raman spectrum of YVO4crystal to the near-IR regime, with seven wavelengths covered at the same time, paving the way for new wavelength generation in the near-IR regime and its multiwavelength application. [ABSTRACT FROM AUTHOR]

A compact diode-side-pumped Tm:YAG laser is presented, which can output 51 W of cw power at 2.02mm. The Tm:YAG rod is side pumped by nine diode arrays with the central wavelength of 783nm and the with bandwidth of about 2.5 nm at 25deg C. To decrease the thermal effect on the both ends and dissipate the heat effectively, one composite Tm:YAG rod with the undoped YAG end caps and the screw threads on the side surface of the rod is used as the laser crystal. The maximum optical-to-optical conversion efficiency of the 2.02-mm laser output is 14.2%, with a slope efficiency of 26.8%. [ABSTRACT FROM AUTHOR]

The solid-state lasers provide an attractive approach to enhance the laser performance benefitting from significant improvements in both thermo-optic and spectroscopic properties of the gain mediums under cryogenic temperature. Here, thermo-optic properties of Yb:Gd 3 (Al x Ga 1-x) 5 O 12 (x = 0.1, Yb:GAGG) and Nd:Gd 3 (Al x Ga 1-x) 5 O 12 (x = 0.2, Nd:GAGG) laser crystals, including thermal conductivity (κ), thermal expansion coefficient (α) and specific heat at constant pressure (C p ) were measured from 77 to 298 K. In addition, the thermal shock resistance parameters were also calculated. The spectroscopic properties and the fluorescence lifetimes of laser gain mediums Yb:GAGG, Nd:GAGG and Nd:Gd 3 Ga 5 O 12 (Nd:GGG) were characterized at 77, 150, 298 K. • Thermal properties of Nd:GAGG, Yb:GAGG are reported at cryogenic temperatures. • Spectroscopic properties of Nd:GGG, Nd:GAGG, Yb:GAGG are reported at 77, 150, 298 K. • Thermal shock resistance parameter is calculated at cryogenic temperatures. • Cryogenic GAGGs have potential application in high power solid state laser. [ABSTRACT FROM AUTHOR]