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Highlights • High-power passively Q-switched Tm:CYA lasers at short wavelengths have been operated. • The operating wavelength was tuned from 1848 to 1876 nm, for the first time. • The tunable Tm:CYA laser is very potential in neural stimulation applications. Abstract Laser emission between about 1850 and 1880 nm is of great interest for neural stimulation applications. We report here on the diode-pumped, continuous-wave and passively Q-switched laser operation of Tm:CaYAlO 4 in this specific wavelength domain, for the first time to our knowledge. In the continuous-wave regime, the maximum output power reaches 5.35 W at 1864 nm with a laser slope efficiency of about 40.5%. Using a Cr:ZnSe saturable absorber, passive Q-switching is achieved with a maximum average output power of 2.37 W at 1857 nm. The narrowest laser pulse width is found to be about 59 ns for a repetition rate of 35.3 kHz and the corresponding laser pulse peak power and pulse energy are about 1.145 kW and 67.5 μJ, respectively. By introducing an undoped YAG crystal as intracavity etalon, tunable and passively Q-switched laser operation is obtained between 1848 and 1876 nm while keeping high pulse energies and peak powers. [ABSTRACT FROM AUTHOR]

We report on a diode-pumped Tm:Gd 3 Ga 5 O 12 (GGG) laser at 2004 nm operated in continuous-wave mode with two-mirror linear cavity configuration. The maximum output power reaches 0.58 W with laser threshold absorbed pump power of about 0.39 W and overall slope efficiency of about 18.4%, which is believed to be the highest output power for Tm:GGG laser up to now. The Tm:GGG laser shows obvious thermally induced saturation of the output power, which indicated that power and efficiency scaling could be furtherly realized by more efficient thermal removal of the laser crystal. [ABSTRACT FROM AUTHOR]

We report diode-pumped Nd:LuYAG mixed crystal lasers around 1.06 μm. In free running mode, single wavelength laser at 1063.88 nm is obtained with maximum output power of 8.71 W and slope efficiency of 60.4%. The laser result represents the best laser performance of Nd:LuYAG laser so far. Using an undoped YAG thin plate to act as intracavity etalon, four simultaneous dual-wavelength lasers can be yielded, i.e. 1064.12 and 1060.95 nm with maximum output power of 4.32 W and slope efficiency of about 31.6%, 1064.37 and 1072.89 nm with maximum output power of 2.06 W and slope efficiency of about 15.0%, 1063.88 and 1052.41 nm with maximum output power of 1.82 W and slope efficiency of about 14.4%, as well as 1063.88 and 1068.26 nm with maximum output power of 1.51 W and slope efficiency of about 13.1%. These dual-wavelength lasers are all generated for the first time to our knowledge in Nd:LuYAG crystal. The multiple peak structure of the Nd:LuYAG mixed crystal like Nd:YAG single crystal could be a potential laser source for THz wave generation. [ABSTRACT FROM AUTHOR]

Single-mode oscillation of a diode-pumped conventional Nd:YAG laser at 1835 nm is demonstrated, for the first time to our knowledge, in the form of microchip configuration. The achieved maximum output power reaches 189 mW with slope efficiency of about 5.5% with respect to absorbed pump power. The laser spectra are measured with linewidth less than 0.08 nm indicating a single longitudinal mode. The output laser beam is also measured to be near diffraction-limited with M 2 factors of about 1.2 and 1.5 in x and y directions. Using a mechanical chopper with 50% duty cycle, the maximum output power is improved to 253 mW with slope efficiency of about 9.7%. [ABSTRACT FROM AUTHOR]

We report a power scaled laser operation of diode-pumped Nd:LSO lasers at 1.35 μm. With single-end-pumping scheme, maximum output power reaches 0.77 W at 1358.99 nm in free-running mode. By inserting an etalon, wavelength tuning can be realized with tuning range of at least 6.5 nm from 1356.95 nm to 1363.39 nm. Simultaneous dual-wavelength laser at 1331.63 and 1357.43 nm can also be generated with total output power of 0.19 W, for the first time to our knowledge. Further power scaling to 1.03 W of the 1358.99 nm laser is finally achieved by recycling the remaining pump power, which represents the highest output power so far for 1.3 μm silicate lasers. [ABSTRACT FROM AUTHOR]

We report a free-running orthogonally polarized dual-wavelength laser at 1313 and 1321 nm with maximum total output power of about 1.73 W using a two-mirror linear cavity. By inserting an etalon into the linear cavity, single-wavelength lasers at 1317 or 1323 nm, two-wavelength lasers at 1317 and 1323 nm, as well as four-wavelength lasers at 1313, 1317, 1323 and 1370 nm can be achieved with maximum output powers of about 0.73, 0.63, 0.78 and 0.25 W, respectively. About 10-nm wavelength tunability from about 1313 to 1323 nm is also realized by inserting the etalon into a three-mirror V-type Nd:YLF laser cavity. [ABSTRACT FROM AUTHOR]

We report diode-pumped continuous-wave (CW) and Q-switched Nd:GYSO lasers using a compact two-mirror linear laser cavity. Single-wavelength laser emissions at 1074.11 nm with 4.1-W power and at 1058.27 nm with 1.47-W power have been obtained in CW mode. The slope efficiencies with respect to the absorbed pump powers are 48.5% and 22.9%, respectively. Wavelength tunability is also demonstrated with range of about 8 nm. Using a MoS 2 saturable absorber, maximum average output power up to 410 mW at 1074 nm can be yielded with absorbed pump power 6.41 W and the maximum pulse energy reaches 1.20 μJ with pulse repetition rate of 342.5 kHz and shortest pulse width of 810 ns. The CW laser results represent the best laser performance and the Q-switching also present the highest output power for Q-switched Nd 3+ lasers with MoS 2 as saturable absorber. [ABSTRACT FROM AUTHOR]

Calibrated room temperature polarized emission spectra recorded between 850 and 1400 nm and nearly free from any reabsorption effect are presented for the first time. A laser output power of 2.35 W is obtained at 1063.45 nm with a laser slope efficiency of about 56% by pumping an uncoated Nd:LaF 3 single crystal with a fiber-coupled laser diode at 790 nm inside a standard two-mirror linear laser cavity. True dual-wavelength laser operation on two orthogonally polarized laser lines around 1040 and 1065 nm as well as continuous laser wavelength tuning around 1040 nm, 1048 nm and 1064 nm are also achieved for the first time by using either an intracavity etalon or a birefringent filter. Laser operation is finally obtained around 1330.73 nm with a maximum output power of 0.18 W and a laser slope efficiency of about 4% and simultaneous dual-wavelength laser operation at 1329.04 and 1359.67 nm is demonstrated by using a glass etalon. [ABSTRACT FROM AUTHOR]