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We report on a high-power Ho:YAG single-crystal fiber (SCF) laser inband pumped by a high-brightness Tm-fiber laser at 1908 nm. The Ho:YAG SCF grown by the micro-pulling-down technique exhibits a propagation loss of $0.05\pm 0.005~\text{cm}^{-1}$ at $2.09~\unicode[STIX]{x03BC}\text{m}$. A continuous-wave output power of 35.2 W is achieved with a slope efficiency of 42.7%, which is to the best of our knowledge the highest power ever reported from an SCF-based laser in the 2 $\unicode[STIX]{x03BC}\text{m}$ spectral range. [ABSTRACT FROM AUTHOR]

A diode-end-pumped continuous-wave and passively Q-switched mode-locked Nd:(Gd0.3Y0.7)2SiO5 laser was designed. At a pump power of 0.8W, we achieve dual-wavelength continuous-wave (CW) laser generation at wavelengths around 1,073.26 and 1,076.62 nm. Using a semiconductor saturable absorber mirror (SESAM), we obtain passively Q-switched mode-locked (QML) operation. A maximum average output power of 171 mW is obtained under a pump power of 5 W. The optical conversion efficiency for the QML laser is 3.4%. The duration of the mode-locked pulse is estimated to be about 649 ps at a repetition rate of 101.34 MHz. [ABSTRACT FROM AUTHOR]

Efficient dual-wavelength continuous-wave (CW) and passively Q-switched laser operation of Nd:(Gd 0.3 Y 0.7 ) 2 SiO 5 crystal were investigated for the first time to our knowledge. Maximum CW output power of 2.3 W was obtained under the absorbed pump power of 4.6 W, corresponding to the slope efficiency of 55%. Dual-wavelength CW laser with respective wavelengths around 1074 nm and 1078 nm were achieved. With Cr 4+ :YAG as the saturable absorber, passive Q-switched performance was obtained. The slope efficiency of passively Q-switched operation was 45%. The shortest pulse width, the corresponding pulse energy and peak power were calculated to be 13.1 ns, 50.2 μJ and 3.8 kW, respectively. [ABSTRACT FROM AUTHOR]

We demonstrated an efficient and controllable dual-wavelength continuous-wave (CW) laser of Nd:Lu 2 SiO 5 (Nd:LSO) crystal. The maximum output power was 3.02 W at wavelength of 1075 nm and 1079 nm, and with increasing of absorbed pump power, the ratio of 1079 nm laser rose. The slope efficiency of 65.6% and optical-to-optical conversion efficiency of 63.3% were obtained. The passively Q-switched laser properties of Nd:LSO were investigated for the first time. The shortest pulse, maximum pulse energy and peak power were 11.58 ns, 29.05 μJ and 2.34 kW, respectively. [ABSTRACT FROM AUTHOR]

Single crystals fiber (SCF) of LuAG doped with 2.0 at.% thulium has been grown by using micro-pulling down (µ-PD) technique. A continuous-wave output power of 2.44 W was achieved with a slope efficiency of 11.7% using a 783-nm diode laser as pump source. The beam quality factors M2 were 1.14 and 1.67 in the x and y directions, respectively. This is, to the best of our knowledge, the first report on the Tm:LuAG SCF laser. Using ray tracing analysis, the influence of laser performance by the pump intensity distribution in the SCF was also studied. [ABSTRACT FROM AUTHOR]

Here, we demonstrate the broadband spectra and efficient laser performance of a disordered Nd:Sr0.7La0.3Mg0.3Al11.7O19 (Nd:ASL) crystal. The polarized absorption and emission spectra were characterized and calculated with the Judd–Ofelt (J–O) theory, and the results show that this crystal has relatively large σ polarized absorption and emission cross sections, with peak emission cross sections of 4.5 × 10−20 cm2 at 1051 nm and an emission width of 30 nm at 1074 nm, which are favorable for pulsed lasers. The laser-diode-pumped continuous-wave (CW) and passively Q-switched lasers at 1051 nm were realized for the first time to our best knowledge. For CW laser, the maximum output power was 1.95 W with the slope efficiency of 42.6%, and for the passive Q-switching, the maximum output power was 0.73 W with the pulse width of 7.96 ns and peak power of 5.64 W. The results demonstrate that Nd:ASL crystal is a potential candidate for lasers, especially high-peak pulsed lasers such as Q-switching and mode-locking. [ABSTRACT FROM AUTHOR]

We report comparative studies on diode-pumped eye-safe Nd:LuAG ceramic lasers at 1.4 μm spectral region in continuous-wave regime. Six differently doped samples have been used to experimentally determine the optimized laser results. A maximum output power of 1.78 W is achieved with simultaneous dual-wavelength laser emission at 1418 and 1442 nm, which is believed the highest output power of Nd:LuAG ceramic at this specific wavelength. Using a V 3+ :YAG as saturable absorber, passively Q-switched Nd:LuAG ceramic laser is also realized, for the first time to our knowledge, with maximum average output power of 0.58 W and pulse width of about 34 ns at pulse repetition rate of 11.91 kHz, which lead to pulse energy of 49.3 μJ and pulse peak power of 1.43 kW. [ABSTRACT FROM AUTHOR]

The absorption spectrum, fluorescence spectrum and fluorescence time of a mixed sesquioxide Nd:LuYO 3 ceramic were measured at room temperature. Judd-Ofelt theory was applied to calculate the spectral parameters of Nd:LuYO 3. The absorption cross section at 812 nm was calculated to be 0.99 × 10−20 cm2 with full width at half maximum (FWHM) of 47.69 nm. The emission cross-section at 1077 nm was calculated to be 5.24 × 10−20 cm2 with FWHM of 11.62 nm. The fluorescence lifetime and quantum efficiency of the 4F 3/2 multiplet were determined to be 228.4 μs and 85.2%, respectively. Continuous-wave (CW) laser operation of Nd:LuYO 3 ceramic was demonstrated. Simultaneous laser operation at 1075.24 and 1080.03 nm was achieved with maximum output power of 490 mW and slope efficiency of 6.36%. • Nd:LuYO3 ceramic was fabricated by solid-state reaction. • Judd-Ofelt theory was used to analyze the spectroscopic properties of Nd:LuYO 3 ceramic. • CW laser operation was performed and output power of 490 mW at the absorbed power of 9.1 W is obtained. [ABSTRACT FROM AUTHOR]

Tm3+-doped calcium niobium gallium garnet (Tm:CNGG) single crystals have been successfully grown by the micro-pulling-down (μ-PD) method. The crystal structure, absorption spectra, fluorescence spectra and lifetimes of Tm:CNGG crystals were investigated. The absorption and emission bandwidths of Tm:CNGG crystals are larger than those of other Tm3+ doped garnet crystals, which will be beneficial for laser diode (LD) pumping and ultrashort pulse generation. Additionally, continuous wave (CW) laser operation around 2 μm was achieved in the 2.0 at.% Tm:CNGG crystal by LD pumping. [ABSTRACT FROM AUTHOR]

Pr3+-doped Sr 0.5 La 0.5 Mg 0.5 Al 11.5 O 19 (ASL) crystal along 〈100〉 direction was successfully grown using the Czochralski technique under azote atmosphere. Absorption and emission spectra of Pr:ASL crystal have been measured at room temperature. Continuous-wave laser operation of the a-cut and c-cut Pr:ASL samples under InGaN laser diode pumping has been demonstrated. For deep red laser operation at about 726 nm, the maximum output powers achieved from a-cut sample was 92.8 mW with slope efficiency of about 11.9%, while 46.6 mW with slope efficiency of 8.0% for the c-cut sample. For red laser at about 645 nm, maximum output powers of 49.2 mW and 42.8 mW were obtained for the a-cut sample and c-cut sample, corresponding to a slope efficiency of 6.7% and 8.5%, respectively. • Pr:Sr 0.5 La 0.5 Mg 0.5 Al 11.5 O 19 crystal was successfully grown using the Czochralski method. • Spectral parameters of Pr:Sr 0.5 La 0.5 Mg 0.5 Al 11.5 O 19 crystal were obtained. • Red and deep red laser were demonstrated in Pr:Sr 0.5 La 0.5 Mg 0.5 Al 11.5 O 19 crystal. [ABSTRACT FROM AUTHOR]

Abstract We report on the growth, spectroscopic properties and visible laser operation of Pr3+-doped LaMgAl 11 O 19 (LMA) crystal. The absorption and emission spectra were recorded in visible wavelength range and the decay time of 3P 0 manifold was measured to be about 34.5 μs at room temperature. Using an InGaN laser diode as pump source, continuous-wave laser operation of Pr:LMA crystal have also been demonstrated in red at about 645 nm and deep red at about 725 nm, which provide new linearly polarized sources for various potential applications. Highlights • A Pr:LMA crystal was successfully gown by using the Czochralski method. • Spectral parameters of Pr:LMA crystal were obtained. • Using a blue laser diode as pump source, red and deep red laser were demonstrated from Pr:LMA crystal. [ABSTRACT FROM AUTHOR]

Abstract We report on diode-pumped continuous-wave and passively Q-switched c-cut Nd:LMA lasers. For continuous-wave operation, the maximum output power reaches 3.10 W with slope efficiency of about 48.9% at 1055 nm and 2.63 W with slope efficiency of 43.1% at 1082 nm. For passively Q switched operation, using a Cr:YAG as saturable absorber, the achieved maximum average output power is 1.49 W at 1055 nm with pulse width of 18.4 ns. Moreover, we have also realized simultaneous dual-wavelength laser operation at 1055 and 1082 nm with a maximum average output power of 1.22 W and a pulse width of 19.4 ns. Furthermore, inserting an etalon for suppressing the 1055 nm line, we have operated single wavelength laser at 1082 nm with output power of 0.31 W and pulse width of 20.8 ns. This work has verified the potential of Nd:LMA crystal as a laser gain medium. Highlights • Absorption and emission spectra of a c -cut Nd: LaMgAl 11 O 19 crystal are reported. • Efficiently continuous-wave operation at 1055 and 1082 nm have been realized for the first time to our knowledge. • Efficiently passively Q-switched operation at 1055 and 1082 nm have also been realized. [ABSTRACT FROM AUTHOR]

• 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 investigated the 1443.9 nm laser characteristics of Nd:GdLuAG crystal. Diode-end-pumping configuration was employed under both continuous-wave (CW) and passively Q- switched operations. For CW operation, the maximum average output power was 1.36 W with a slope efficiency of 15%. By using a V 3+ :YAG crystal as the saturable absorber, we obtained the maximum average output power of 164 mW under Q -switched operation. The corresponding pulse energy was 29.3 μJ and pulse duration was 59 ns. [ABSTRACT FROM AUTHOR]

Ho3+-doped CaY 0.9 Gd 0.1 AlO 4 single crystal was successfully grown by the Czochralski technique for the first time. The polarized absorption spectra, polarized luminescence spectra and fluorescence decay curve of the crystal were investigated at room temperature. The spectroscopic parameters are calculated based on Judd–Ofelt theory, the values of Ω 2,4,6 were calculated to be 3.16 × 10−20 cm2, 3.93 × 10−20 cm2, 0.91 × 10−20 cm2, respectively. The Ho:CaY 0.9 Gd 0.1 AlO 4 crystal exhibits strong emission at 2013 nm for π- and 2032 nm for σ-polarizations with stimulated emission cross section of 6.64 × 10−20 cm2 and 1.90 × 10−20 cm2, respectively. The fluorescence lifetime of the 5I 7 level was measured to be 6.60 ms. The continuous-wave (CW) laser operation of Ho:CaY 0.9 Gd 0.1 AlO 4 crystal around 2 μm was demonstrated. • Ho3+-doped CaY 0.9 Gd 0.1 AlO 4 single crystal was successfully grown by the Czochralski technique for the first time. • The emission cross-section at 2013 nm and 2032 nm are 6.64 × 10−20 cm2 and 1.90 × 10−20 cm2 for π- and σ-polarizations respectively. • The continuous-wave (CW) laser operation of Ho:CaY 0.9 Gd 0.1 AlO 4 crystal around 2 μm was demonstrated. [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]

In this paper, we have demonstrated a continuous-wave (CW) dual-wavelength Yb:LuYAG laser which works at 1029.41 and 1047.16 nm simultaneously. The laser operation state of dual-wavelength can be adjusted continuously by change the angle of the cavity mirror. And passively Q-switched operation of the crystal Yb:LuYAG was proceeded at the wavelength of 1028.99 nm using the MoS 2 saturable absorber. The pulse duration and maximum repetition rate were 293 ns and 251.27 kHz, respectively. [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]