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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 diode-pumped Nd:LuAG crystal lasers on 4 F 3/2 → 4 I 11/2 transition around 1.1 μm in continuous-wave and passive Q-switching regimes. For continuous-wave laser operation, a dual-wavelength laser at 1117 and 1122 nm is achieved with maximum output power of 5.82 W and slope efficiency of about 42.8%, which is believed to be the highest output power of Nd:LuAG lasers at 1.1 μm. Using an etalon to tune the lasing wavelength, a single-wavelength laser at 1114 nm is also realized, for the first time to our knowledge, with maximum output power of 4.11 W. Further wavelength tuning from 1113.9 to 1122.6 nm is also obtainable. Passively Q-switched laser operation at 1122 nm is finally performed with a maximum average output power of 0.73 W, the narrowest pulse width of 21.2 ns and a maximum pulse repetition rate of 14.12 kHz, which leads to a maximum pulse peak power of 2.43 kW and a maximum pulse energy of about 51.7 μJ. [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]

• We report the highest output power (12.36 W) of diode-pumped Tm:CALYO laser at 1938 nm with a slope efficiency of 53.9%. • We report the broadest tunability (271 nm) for Tm:CALYO lasers. • Passively Q-switched operation was also achieved with a maximum average output power of 3.81 W and pulse width of 25.9 ns. We report on the recent progress on high-power and broadband wavelength tunability of diode-pumped Tm:CaYAlO 4 (Tm:CALYO) lasers. Using a double-end pumping geometry, we have achieved a maximum output power of 12.36 W at 1938 nm, which is believed to be the highest power that have ever achieved for Tm:CALYO lasers. Moreover, we have operated 1861 nm, 1982 nm and 2032 nm lasers with maximum output powers of 8.73 W, 5.36 W and 0.73 W, respectively, by using differently coated end-face cavity mirrors. Furthermore, using a MgF 2 birefringent filter, we have tuned the lasing wavelengths from 1807 nm to 2078 nm. The 271 nm wavelength range is also believed to be the broadest tunability for Tm:CALYO lasers. Passively Q-switched Tm:CALYO laser has also been demonstrated with a maximum average output power of 3.81 W. The shortest pulse width reached 25.9 ns at a repetition rate of 10.1 kHz, which led to a pulse energy of 377.22 μJ and a peak power of 14.56 kW. These results indicate clearly that the Tm:CALYO crystal is excellent as a high-power and broadband laser gain medium operating at the important 2 μm wavelength region. [ABSTRACT FROM AUTHOR]

• A Pr:YLF-based single-frequency orange laser at 607 nm has been first demonstrated. • A Pr:YLF-based single-frequency orange laser at 604 nm has been first demonstrated. • The single-frequency orange lasers have potential application in biomedicine. We report on blue diode-pumped single-frequency Pr:YLF lasers in orange spectral region, for the first time to the best of our knowledge. For a single-frequency σ-polarized 607 nm laser, a maximum output power up to 175 mW is achieved with a slope efficiency of about 16.6%. Linewidth of the 607 nm single-frequency laser is measured to be about 6 MHz. Single-frequency operation has also been obtained at π-polarized 604 nm laser with a maximum output power up to 91 mW and a slope efficiency of about 8.9%. The corresponding linewidth of the 604 nm laser is about 22 MHz. The two single-frequency orange lasers exhibit wavelength tuning ranges of about 0.15 nm and 0.35 nm, respectively. This work has proposed the simplest way for single-frequency laser generation in orange spectral region, which could be obtained by complicated and low-efficiency sum-frequency mixing of Nd3+ lasers. This work paves a practical way for various orange-related applications. [ABSTRACT FROM AUTHOR]