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• Laser performance of neodymium-doped gadolinium scandium aluminum garnet (Nd:GSAG) crystals at 1.3 μm was investigated for the first time, to the best of our knowledge. • An efficient continuous-wavelaser at 1336 nm and on output power of up to 2.01 W was obtained under an absorbed pump power of 4.89 W with slope and optical-to-optical efficiencies of 43.4 % and 41.1 %, respectively. • A passively Q-switched laser with a Co:MgAl2O4 crystal serving as a saturable absorber was examined and a maximum average output power of 0.2 W was obtained with a pulse width, pulse energy, and peak power of 34.4 ns, 22.2 µJ, and 645 W, respectively. • Our results indicated that Nd:GSAG crystals are promising for producing high-efficiency CW lasers and effective PQS lasers at 1336 nm. We report on the laser performance of neodymium-doped gadolinium scandium aluminum garnet (Nd:GSAG) crystals at 1.3 μm for the first time, to the best of our knowledge. An efficient continuous-wave (CW) laser at 1336 nm and on output power of up to 2.01 W was obtained under an absorbed pump power of 4.89 W with slope and optical-to-optical efficiencies of 43.4 % and 41.1 %, respectively. Furthermore, a passively Q-switched (PQS) laser with a Co:MgAl 2 O 4 crystal serving as a saturable absorber in a compact plano-plano resonator cavity was examined. A maximum average output power of 0.2 W was obtained with a pulse width, pulse energy, and peak power of 34.4 ns, 22.2 µJ, and 645 W, respectively. Our results indicated that Nd:GSAG crystals are promising for producing high-efficiency CW lasers and effective PQS lasers at 1336 nm. [ABSTRACT FROM AUTHOR]

• The polarized spectra, thermal properties and laser performance of Nd:GdScO 3 crystal were systematically studied in detail. • Nd:GdScO 3 crystal is meaningful for realizing dual-wavelength emissions near 1070–1085 nm, and the maximum emission cross-section is up to 9.405 × 10-20 cm2. • Continuous-wave laser operation at 1.08 µm was realized in Nd:GdScO 3 crystal for the first time, and the maximum output power yields 3.16 W with a slope efficiency of 47.5%. The spectroscopic and thermal properties, and laser performance of Nd:GdScO 3 crystal grown using the Czochralski method were studied in detail. The corresponding XRPD pattern shows that the crystal belongs to the orthorhombic system with the cell parameters of a = 5.487 Å, b = 5.752 Å, and c = 7.940 Å. Polarized absorption and fluorescence spectra were recorded, and the spectroscopic parameters were systematically calculated by the Judd–Ofelt theory. The absorption cross-sections at 806.5 nm are 4.666, 2.479 and 2.354 × 10-20 cm−2 with polarization along the principal a -, b - and c -axis, respectively. The maximum emission cross-section is 9.405 × 10-20 cm2 at 1083.8 nm, and the fluorescence lifetime of 4F 3/2 energy level is found as 147.4 µs. The specific heat of the crystal is 0.382 J g−1 K−1 at 298.15 K, and the principal thermal conductivity components at room temperature are k 1 = 3.24, k 2 = 3.17, and k 3 = 3.11 W m−1 K−1, respectively. Continuous-wave laser operation at 1.08 µm was realized in Nd:GdScO 3 crystal for the first time, and the maximum output power yields 3.16 W with the slope efficiency of 47.5%. [ABSTRACT FROM AUTHOR]

• Detailed spectroscopic properties of Nd:GSAG (Gd 3 Sc 2 Al 3 O 12) were demonstrated; • Discrete multi-wavelength tuning lasers (1047, 1060, 1062, 1065 and 1075 nm) were constructed using a birefringence filter were demonstrated for the first time; • The saturation flux of Nd:GSAG is 2.7 J/cm2 and it is more suitable than Nd:YAG for constructing high-power lasers to reduce AES and store energy. Detailed spectroscopic properties of Nd:GSAG (Gd 3 Sc 2 Al 3 O 12) were demonstrated and discrete multi-wavelength tuning lasers were constructed using a birefringence filter for the first time to our knowledge. Because of the disordered crystal field, Stark levels are widened, and the emission cross sections are restrained to different degrees, bringing about a mitigating amplified spontaneous emission and providing optimal conditions for discrete multi-wavelength lasers output. Therefore, Nd:GSAG has the potential to emerge as a laser possessing multiple wavelengths for application as a fundamental laser source. [ABSTRACT FROM AUTHOR]

The growth and spectroscopic properties of a novel Tm:CaGdAl 3 O 7 crystal were studied for the first time. The XRPD pattern shows that the crystal belongs to the tetragonal system with the cell parameters of a = b = 7.7125 Å and c = 5.0683 Å. The absorption and fluorescence spectra were recorded and the spectroscopic performance was systematically analyzed with the Judd–Ofelt theory. The absorption cross-section was calculated to be 0.542 × 10−20 cm−2 at 788.5 nm with a full width at half maximum (FWHM) of 36 nm. The FWHM of fluorescence spectrum was up to 228 nm, and the determined emission cross-sections were 0.439 × 10−20 cm2 at 1817 nm and 0.388 × 10−20 cm2 at 1940 nm, respectively. The fluorescence lifetime of 3F 4 energy level in Tm:CaGdAl 3 O 7 crystal was found as 4.42 ms. The gain cross-section at the wavelength over 1800 nm becomes positive when the population inversion level reaches 20%. The experimental results show that Tm:CaGdAl 3 O 7 is a promising crystal that can be used in ∼2 μm tunable and ultrashort pulse lasers. • A disordered Tm3+-doped CaGdAl 3 O 7 crystal was firstly grown with its spectroscopic properties studied in detail. • The self absorption of the crystal is very small, and the gain cross section shows that the laser threshold should be relatively low even in the quasi-three level system. • Both broadband absorption and broadband emission in this crystal support the potential applications in ∼2 μm tunable and ultrashort pulse lasers. [ABSTRACT FROM AUTHOR]

• The Pr:LaF 3 crystals with different doping concentrations were grown by the Bridgman method with the dimension is about Φ20 mm × 30 mm. • The effects of Pr3+ doping concentration on the LaF 3 crystal optical properties were expounded for the first time. • The continuous-wave (cw) deep red laser were obtained with different doping concentrations of Pr:LaF 3 crystals pumped by an blue laser diode for the first time. The crystal compositions, fluorescence lifetimes, polarized absorption and emission spectra, and laser performance were measured with different doping concentrations of Pr:LaF 3 crystals. Moreover, the effects of Pr3+ doping concentration on LaF 3 crystal optical properties were expounded for the first time. The study found that high doping concentration is easy to cause cross-relaxation, which in turn leads to a decrease in the lifetime of the laser upper energy level. And then affects the output efficiency of the visible laser. The laser experiment results confirm that the maximum output power of 176 mW was obtained with Pr:LaF 3 crystal of 0.5 at.% doping concentration, which is higher than output power (71.3 mW) of 1 at.% doping concentration crystal. As we all know, this is the first report about continuous-wave (cw) laser operation with Pr:LaF 3 crystal pumped by an blue laser diode. [ABSTRACT FROM AUTHOR]

• The polarized characteristics of a novel Tm:GdScO 3 crystal were studied by both the emission spectra and the continuous-wave laser experiments. • Stable passive Q-switched Tm:GdScO 3 laser was demonstrated for the first time, to the best of our knowledge. • SnS 2 nanosheets were firstly investigated in a Q-switched laser at 2 μm with the modulation depth of 8.8 % and the saturable absorption intensity of 2.46 mJ/cm2, respectively. Thulium-doped orthorhombic gadolinium scandate, Tm:GdScO 3 , is promising for efficient linear polarized continuous-wave (CW) and passively Q-switched lasers near 2 μm. The polarized characteristics of different lasing propagation were verified by both the emission spectra and the laser experiments. Under diode pumping at 793 nm, linear polarized lasers of electric field direction (E) parallel to a - and b -axis are obtained with the maximum output power of 1.87 W and 2.00 W and with the slope efficiency of 27.5 % and 28.4 %, respectively. Stable passive Q-switching of the Tm:GdScO 3 laser using SnS 2 is demonstrated for the first time, to the best of our knowledge. With different output couplers, the 1.99 μJ/460 ns pulses at ∼2 μm were achieved with a maximum average output power of 0.175 W and a peak power of 4.32 W. Tm:GdScO 3 is promising to be the candidate for 2 μm ultrashort lasers. [ABSTRACT FROM AUTHOR]

• The first laser operation of perovskite oxide Nd,Th:LaAlO 3. • Demonstrated optical properties of Nd,Th:LaAlO 3 and cw laser performance. Report, to the best of our knowledge, the first laser operation of perovskite oxide LaAlO 3 doped with 1 at.% Nd ions and 0.2 at.%Th (Nd,Th:LaAlO 3). Optical properties of Nd,Th:LaAlO 3 were demonstrated. We study the influence of Th dopants on the domain structure and spectroscopic properties of LaAlO 3. Under 793 nm diode-pumped excitation, we achieve a continuous-wave laser output at 1080 nm with a slope efficiency of 36 % and an optical-to-optical efficiency of 34 % under a T oc = 5 % output coupler. The emission cross section of Nd,Th:LaAlO 3 reaches 3.65 × 10−20 cm2 at 1080 nm, the saturation flux is 5 J/cm2. The fluorescence lifetime reaches 317 μs and the thermal conductivity is 10.3 W/m·K at 25 °C. Considering its excellent mechanical properties and thermal conductivity, Nd,Th:LaAlO 3 is a promising high-energy pulsed laser material. [ABSTRACT FROM AUTHOR]

• Continuous-wave laser operation at 2 μm of Tm:GdScO 3 crystal were investigated. • Tm3+:3F 4 → 3H 6 (2 μm) of Tm:GdScO 3 crystal exhibits broadband of 269 nm. • Tm:GdScO 3 crystal is promising for broadband tunable and ultrafast lasers. Spectra and laser operation at 2 μm of Tm:GdScO 3 crystal are investigated for the first time. The low symmetry in GdScO 3 crystal broadens emission spectrum (269 nm) of Tm3+:3F 4 → 3H 6 transition, which is the widest in Tm3+ doped crystals. The emission cross-sections at 1975 nm are approximately 0.23 (E//X), 0.23 (E//Y) and 0.28 (E//Z) × 10-20 cm2, respectively. The fluorescence lifetime of Tm3+:3F 4 is 3.68 ms. Pumped by a 793 nm laser diode, the output power yields 4.53 W with the slope efficiency of 25%. All results indicate Tm:GdScO 3 a promising candidate for 2 μm tunable and ultrashort lasers. [ABSTRACT FROM AUTHOR]