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In this paper, we demonstrate a SESAM mode-locked Tm:CaYLuAlO4 (a-cut) laser in the 2-μm spectral range. A birefringent filter (BF) is employed to shift the emission wavelength above 2 μm to support the stable mode locking through avoiding the structured water vapor absorption. Pulses as short as 288 fs are generated with a central wavelength of 2037 nm and an average power of 166 mW at a repetition rate of ~ 77.6 MHz. Moreover, wavelength tunable femtosecond laser with a tuning range from 2031.8 to 2081.1 nm is realized simply by rotating the birefringent filter around its surface normal. This work experimentally shows that birefringent filter is a simple and low-cost way to support the stable mode locking of Tm-bulk femtosecond lasers with an emission peak in the water vapor absorption region. [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]