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• Spectral properties and high-efficiency broadband laser operation of Tm:CYGA crystal at 2 μm were demonstrated. • The maximum continuous-wave output power of 1.43 W was obtained. • A 284.7 nm tuning coverage was realized with a BF. We report on spectral properties and a high-efficiency broadband laser operation of Tm:CaY 0.9 Gd 0.1 AlO 4 (Tm:CYGA) crystal. The polarized absorption and emission spectra, gain cross sections and fluorescence lifetime are systematically studied, presenting a broad absorption and emission spectra and thus a smooth gain band. Furthermore, under an absorbed pump power of 4.35 W, a maximum continuous-wave (CW) laser output power of 1.43 W at 1967.8 nm is obtained, corresponding to a slope efficiency of 42.2 %. The beam quality factors (M2) in X-axis and Y-axis are measured to be 1.011 and 1.027, respectively. A tunable Tm:CYGA laser with a tuning range of 284.7 nm from 1837.5 to 2122.2 nm is achieved employing a birefringent filter (BF). The results indicate that the Tm:CYGA crystal is an excellent laser medium for generating high-efficiency broadband CW laser, indicating its potential for ultrashort pulse generation in the 2-μm spectral range. [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]

• Diode-pumped CW Pr,Mg:SRA lasers at 643 nm, 724 nm and 622 nm are demonstrated. • The highest output power of the diode-pumped Pr,Mg:SRA laser is 675 mW. • Passively Q-switched Pr,Mg:SRA lasers are also demonstrated, for the first time. • The shortest pulse width is 105.6 ns for the 622 nm laser, while 211.7 ns for the 643 nm laser. We report on compact blue-diode-pumped Pr,Mg:SrAl 12 O 19 (SRA) lasers in continuous-wave and passively Q-switched regimes. For continuous-wave mode, three lasers have been achieved with maximum output powers of 675 mW, 566 mW and 312 mW at wavelengths of 643 nm, 724 nm and 622 nm, respectively. The maximum slope efficiencies with respect to absorbed power for the three lasers are 18.7%, 16.6% and 11.1%. Using a uniaxial Co2+-doped strontium, lanthanum and magnesium aluminate (Co:ASL) crystal as saturable absorber with remarkable absorptions at 643 nm and 622 nm, we have achieved passively Q-switched Pr,Mg:SRA lasers at the two emissions with maximum output powers of 175 mW and 118 mW, respectively, for the first time to our knowledge. The shortest pulse widths for the two lasers are 211.7 ns and 105.6 ns. Correspondingly, we estimated that pulse energies and peak power are 2.13 μJ and 10.1 W for the 643 nm laser as well as 0.98 μJ and 9.27 W for the 622 nm laser. This work reveals that Pr,Mg:SRA as one of the few reported Pr3+-doped oxides could be potential in generating compact and efficient lasers in visible spectral range. [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]

• The performance of diode-pumped (Nd3+-doped) Ca 0.7 La 0.3 Al 12 O 19 (Nd:CLA) lasers was studied for the first time. • By inserting a Cr4+:YAG absorber, we successfully achieved a passively Q-switched laser. • Comparation between a- and c-cut disordered Nd:CLA lasers were made. A new neodymium-doped (Nd3+-doped) Ca 0.7 La 0.3 Al 12 O 19 (Nd:CLA) disordered crystal was successfully grown by the Czochralski method. The performance of diode-pumped Nd:CLA (a-cut and c-cut) lasers was demonstrated for the first time. For the c-cut crystal continuous-wave (CW) operation, we obtained the highest output power of 2.08 W at the wavelength of 1053.2 nm, and the slope efficiency was 23% versus the incident pump power. By inserting a Cr4+:YAG absorber, we successfully achieved a passively Q-switched laser, and the shortest pulse width was 18.36 ns with a peak power of 364.6 W. Compared with a-cut crystal, c-cut crystal has superior laser characteristics. [ABSTRACT FROM AUTHOR]