•A bulk crystal of Er3+:Yb3+:LaMgB5O10 was firstly grown by TSSG method.•The polarized absorption and fluorescence spectra were investigated in detail.•A diode-pumped continuous-wave laser was realized in Er3+:Yb3+:LaMgB5O10 crystal.A bulk crystal of Er3+:Yb3+:LaMgB5O10 was grown successfully by the top seeded solution growth (TSSG) method. The spectroscopic characterization of this material, including the polarized absorption and fluorescence spectra and the fluorescence decay curve, were recorded. The fluorescence quantum efficiency of the 4I13/2 level of Er3+ ions and the efficiency of energy transfer from Yb3+ to Er3+ ions were estimated. Continuous-wave laser output of 160 mW at 1567 nm was realized under the absorbed pump power of 3.1 W in a hemispherical cavity. When the output coupler transmission was 1.7% the absorbed pump threshold was 1.5 W and the slope efficiency of the laser was 10.1%. The results show that Er3+:Yb3+:LaMgB5O10 crystal is a promising laser material.

Two novel solid solutions of Yb:YAG and Ca3Al2(SiO4)3, Yb:YAG and Mg3Al2(SiO4)3 in various molar ratios were synthesized by solid-state reactions, respectively. The spectral bandwidth remarkably increased with increasing M3Al2(SiO4)3 (M=Ca and Mg) contents, and the maximal full width at half maximum (FWHM) of absorption and emission spectra for the solid solutions are almost 9 and 3 times larger than that of Yb:YAG, respectively. This large broadening of spectral bandwidth can be attributed to the inhomogeneity in the local environment of Yb3+ caused by the cationic substitutions of Ca2+ (Mg2+) for Y3+, Si4+ for Al3+ and the high crystal-field strengths caused by distorted host sites. Meanwhile, the fluorescence lifetimes of solid solutions decrease with the increases of M3Al2(SiO4)3 contents.

A bulk crystal of Yb-doped GdMgB5O10 was firstly grown successfully by the top seeded solution growth method. The spectroscopic properties were characterized in terms of polarized absorption and fluorescence spectra, and lifetime measurement. Stark energy level diagram for the Yb3+:GdMgB5O10 crystal was analyzed. Corresponding absorption and emission cross-sections, the gain cross-sections were calculated. A maximum laser output power 5.35 W was attained with corresponding to an optical-to-optical efficiency of 50.8% and a slope efficiency of 56%. The results show that Yb3+:GdMgB5O10 crystal is a promising laser medium.

A Yb3+-doped Sr3Gd2(BO3)4 (Yb:SGB) crystal was grown using the Czochralski method. A systematic investigation of the disordered structure characteristics, polarized spectral properties and continuous wave (CW) laser performances of this crystal was reported for the first time. Due to the statistical distributions of Gd3+ and Sr2+ ions, the absorption and emission spectra are strongly inhomogeneously broadened when introducing Yb3+ in the host. This feature of the broad spectra facilitates efficient pumping of InGaAs diodes and production of ultrafast pulse lasers. A maximum CW laser output power of 2.82 W under an absorbed pump power of 6.4 W was achieved with a central wavelength of 1055 nm, corresponding to a slope efficiency of 54% and an optical conversion efficiency of 44%. The results reveal that Yb:SGB is an excellent candidate for an ultrafast pulse laser crystal.

•The Yb:SYB crystal with high Yb3+ concentration was grown using Czochralski method.•SESAM mode-locking performances of Yb:SYB crystal were reported for the first time.•Sub-120-fs pulses lasers were generated from Yb:SYB based oscillators.•The corresponding slope efficiencies could reach to 49–54%.•The optical to optical efficiencies could reach to 31–33%.A systematic investigation of the spectroscopy properties and semiconductor saturable absorber mirror mode-locking performances of highly doped Yb:Sr3Y2(BO3)4 (Yb:SYB) crystal was reported for the first time. The broad emission spectral bands indicate the great potential of Yb:SYB for ultrafast laser applications. 116 fs, 120 fs and 126 fs pulses lasers were generated with more than 1 W average output power from the a-cut, b-cut and c-cut Yb:SYB based oscillators, respectively. The corresponding slope efficiencies and optical to optical efficiencies could reach to 49–54% and 31–33%, respectively. The experimental results show the excellent potential of Yb:SYB crystal for generating highly efficient femtosecond lasers.Figure optionsDownload full-size imageDownload as PowerPoint slide

•Cr3+:MgWO4 crystal was grown successfully by the top-seeded solution growth method.•Cr3+:MgWO4 crystal has weak anisotropic thermal expansion and large thermal conductivity.•Cr3+:MgWO4 crystal has broad and strong absorption and emission bands.•The results show that Cr3+:MgMoO4 crystal is a good potential tunable laser gain medium.This paper reports the growth, thermal and polarized spectral properties of Cr3+:MgWO4 crystal. Cr3+:MgWO4 crystal with dimensions of 20×18×13 mm3 was grown successfully by a top-seeded solution growth method. The average thermal expansion coefficients are 10.47×10−6 K−1, 15.68×10−6 K−1 and 10.75×10−6 K−1 along a-, b- and c-axis, respectively. The thermal conductivity is 8.69 W/(m K) at room temperature. Both of the absorption and emission spectra show strong polarization characteristics. There is a broad and strong absorption band at around 790 nm, which means that Cr3+:MgWO4 crystal is suitable for AlGaAs laser diode pumping. The crystal has a broad emission band at 961 nm with a full width at half-maximum of 202 nm; the emission cross-section is about 1.8×10−19 cm2. The results show that Cr3+:MgMoO4 crystal can be regarded as a potential tunable laser gain medium.

•Nonlinear refractive index of Yb:Sr3Y2(BO3)4 crystal was studied for the first time.•Ultrafast laser performance of Yb:Sr3Y2(BO3)4 was demonstrated for the first time.•The SESAM-assisted Kerr-lens mode-locked Yb:SYB laser generated 58 fs pulses with a maximum average output power of 400 mW.The ultrafast laser performance of Yb:Sr3Y2(BO3)4 (SYB) crystal has been demonstrated for the first time to the best of our knowledge. The Yb:SYB laser was driven to work in SESAM-assisted Kerr-lens mode-locking (KLM) operation, and 58 fs pulses were generated at the central wavelength of 1054.6 nm. A maximum average output power reached 400 mW with a slope efficiency of 13.5%. The experimental results indicated Yb:SYB crystal as a promising candidate for achieving ultrashort lasers.

A bulk crystal of Yb3+:LaMgB5O10 was grown successfully by the top seeded solution growth method for the first time to our knowledge. The detailed crystal structure data was given, revealing that the Yb3+:LaMgB5O10 crystal belongs to the monoclinic system with the space group P21/n, and its unit cell parameters are: a = 8.8002 Å, b = 7.6136 Å, c = 9.4900 Å, β = 92.46°, V = 635.3 Å3 and Z = 4. Investigation of its polarized spectral properties shows that the Yb3+:LaMgB5O10 crystal has broad, strong absorption and emission cross-sections. A continuous wave laser output of 2.76 W with a slope efficiency of 64.5% was obtained; the laser simultaneously oscillated at 1053 and 1057 nm at a pump power of 7.7 W. The results show that the Yb3+:LaMgB5O10 crystal is a promising laser crystal.

•A Yb3+:Sr3Y2(BO3)4 crystal was grown successfully by Czochralski method.•The crystal has wide absorption and emission bandwidth.•3.47 W continuous wave laser output with a slope efficiency of 29% was obtained.•The results show that the crystal is a promising ultrashort pulse laser material.A Yb3+:Sr3Y2(BO3)4 crystal was grown successfully by the Czochralski method. The polarized spectral properties and continuous wave laser output of this crystal were investigated in detail. The crystal has larger absorption and emission cross sections compared with many mature Yb3+-doped borate crystals. The full width at half maximum of the emission bands around 1023 nm are 69 nm (E//a), 61 nm (E//b) and 65 nm (E//c). 3.47 W continuous wave laser output with a slope efficiency of 29% and an optical conversion efficiency of 24% was obtained. The results reveal that Yb3+:Sr3Y2(BO3)4 crystal is an excellent candidate for ultrashort pulse laser crystal.

A Ca9Yb(VO4)7 crystal with dimensions of Φ23 mm×35 mm was grown successfully by Czochralski method. Its thermal conductivity was 1.06 W/(m·K) at room temperature. The absorption cross-sections at 980 nm were 1.80×10−20 cm2 and 1.28×10−20 cm2 for π-and σ-polarizations, respectively, with a full-width at half-maximum of 34 nm. The crystal had a broad emission at around 1025 nm with a full-width at half-maximum of 67 nm for π-polarization and 70 nm for σ-polarization. The emission cross-sections of the crystal were calculated by using reciprocity method and Füchtbauer-Ladenburg formula. The emission cross-sections at 1025 nm were 3.57×10−20 cm−2 and 1.91×10−20 cm−2 for π- and σ-polarization, respectively. The fluorescence lifetime was 332 μs. The results indicated that the crystal is a promising femtosecond and tunable laser material.Polarization absorption and fluorescence spectra of Ca9Yb(VO4)7 crystal

•Nd3+:Sr6YSc(BO3)6 crystal was grown successfully by TSSG method from a Li6B4O9 flux.•Nd3+:Sr6YSc(BO3)6 crystal has good mechnical, thermal and spectral properties.•Nd3+:Sr6YSc(BO3)6 crystal is a potential laser material.A crystal of Nd3+:Sr6YSc(BO3)6 was grown successfully by the top-seeded solution growth method. The average laser-induced damage thresholds are 1.76 GW/cm2 for (0 0 1) face and 1.47 GW/cm2 for (1 0 0) face at 1064 nm radiation, respectively. The average Vickers hardness of (1 0 0) and (0 0 1) faces are 629 and 545 N/mm2, respectively. The thermal expansion coefficients are 12.3 × 10−6 K−1 along a-axis and 9.39 × 10−6 K−1 along c-axis, respectively. The thermal conductivity is about 2.3 W/m K at room temperature. The polarized spectral properties were investigated in detail. Based on the Judd–Ofelt theory, the intensity parameters were obtained. The results show that Nd3+:Sr6YSc(BO3)6 crystal is a potential laser crystal.

•A β′-Yb:Gd2(MoO4)3 crystal was grown successfully by the Czochralski method.•The intensity of SHG of β′-Yb:Gd2 (MoO4)3 is about 3 times as large as that of KDP.•β′-Yb:Gd2(MoO4)3 has negative thermal expansion and moderate thermal conductivity.•The crystal is suitable for LD pumping and easy to realize laser oscillation.•β′-Yb:Gd2(MoO4)3 is a promising self-frequency doubling laser crystal.A β′-Yb3+:Gd2 (MoO4)3 crystal with dimensions of 22×22×25 mm3 was grown successfully by the Czochralski method. Its relative efficiency of second harmonic generation was measured by Kurtz power method, the intensity is about 3 times as large as that of KH2PO4 crystal. The thermal expansion coefficients of the crystal are 14.7×10−6 K−1, 13.5×10−6 K−1 and −20.1×10−6 K−1 along a-, b- and c-axes, respectively. The thermal conductivity along the c-axis is 1.44 W/m K at room temperature. The absorption cross section at 977 nm is 0.48×10−20 cm2 with full width at half maximum of 20 nm. The emission cross section at 1030 nm is 1.13×10−20 cm2. The fluorescence lifetime is 722 μs. The results indicate that β′-Yb:Gd2(MoO4)3 crystal is a promising candidate of self-frequency doubling laser material.

Er3+/Yb3+:Ca9Y(VO4)7 crystal with dimensions of Ø 20×25 mm2 was grown successfully by the Czochralski method. Its thermal and spectral properties were investigated in detail. The thermal expansion coefficients are 1.39×10−5 K−1 and 1.63×10−5 K−1 along a-axis and c-axis, respectively. The thermal conductivity is about 1 W/(m K) at room temperature. The absorption bands near 980 nm have a full-width at half-maximum of 37 nm and 26 nm for σ- and π-polarization, respectively. The fluorescence lifetime of the 4I13/2 level of Er3+ is 4.12 ms. The emission cross sections calculated by the Füchtbauer–Ladenburg method at 1533 nm are 1.58×10−20 cm2 and 1.57×10−20 cm2 for σ- and π-polarization, respectively. The results indicate that Er3+/Yb3+:Ca9Y(VO4)7 crystal is a potential 1.5–1.6 μm laser material.

•A new crystal of Yb3+:Sr6YSc(BO3)6 was grown successfully from a Li6B4O9 flux.•Yb3+:Sr6YSc(BO3)6 crystal has good thermal, mechanical and spectral properties.•Yb3+:Sr6YSc(BO3)6 has long fluorescence lifetime, broad absorption and emission bands.A crystal of Yb3+:Sr6YSc(BO3)6 was grown successfully from Li6B4O9 flux by the top-seeded solution growth method. The crystal's thermal, mechanical and spectral characteristics were investigated in detail. It possesses small thermal expansion coefficients, moderate thermal conductivities, and large hardness. The crystal has a strong absorption band at 967 nm with a full width at half-maximum of about 3.4 nm. The crystal has a broad emission band at 1016 nm with the full width at half-maximum of about 64 nm. The emission cross sections were calculated by reciprocity method and Füchtbauer-Ladenburg formula. The fluorescence lifetime is 5.98 ms. The results reveal that Yb3+:Sr6YSc(BO3)6 crystal is a new promising tunable and ultrashort pulse laser crystal.

•Sr6ErSc(BO3)6 crystal was grown successfully by TSSG method from a Li6B4O9 flux.•Sr6ErSc(BO3)6 crystal has good thermal and spectral properties.•Sr6ErSc(BO3)6 crystal is a potential laser material for 1.55 μm laser.A new crystal of Sr6ErSc(BO3)6 was grown successfully by top seeded solution growth method from a Li6B4O9 flux. Its thermal and spectral properties were investigated in detail. The thermal expansion coefficients are 6.42 × 10−6 K−1 along a-axis, and 9.75 × 10−6 K−1 along c-axis, respectively. The thermal conductivity is about 2.2 W/(m K) at room temperature. The emission cross sections at 1548 nm are 1.7 × 10−21 cm2 for π-polarization, and 2.0 × 10−21 cm2 for σ-polarization, respectively. The fluorescence lifetime of the 4I13/2 manifold is 0.78 ms. The results show that Sr6ErSc(BO3)6 crystal is a potential 1.55 μm laser gain medium material.

•Er3+/Yb3+:Ca9La(VO4)7 crystal was grown successfully by the Czochralski method.•Er3+/Yb3+:Ca9La(VO4)7 crystal has large absorption and emission cross sections.•Laser oscillation likely to be favorable in Er3+/Yb3+:Ca9La(VO4)7 crystal.•Er3+/Yb3+:Ca9La(VO4)7 is a promising material for 1.55 μm lasers.A new crystal of Er3+/Yb3+:Ca9La(VO4)7 was grown successfully by the Czochralski method. Its spectral properties were investigated in detail. The crystal has a strong absorption band near 980 nm with a full-width at half-maximum of 33 nm, which means that it is very suitable for InGaAs laser diode pumping. Based on the Judd-Ofelt theory, the intensity parameters and radiative lifetime were obtained. The fluorescence lifetime of the 4I13/2 level of the Er3+ ion is 4.28 ms. The emission cross sections of the Er3+ ion at 1533 nm calculated by the Füchtbauer-Ladenburg method are 0.86 × 10−20 cm2 and 1.08 × 10−20 cm2 for σ- and π- polarization, respectively. The results indicate that Er3+/Yb3+:Ca9La(VO4)7 crystal is a potential 1.5–1.6 μm laser material.

•Cr3+:CaGdAlO4 crystal was grown successfully by Czochralski method.•Detailed spectral properties of Cr3+:CaGdAlO4 crystal were presented.•Cr3+:CaGdAlO4 crystal shows a narrow R line emission.A Cr3+:CaGdAlO4 single crystal with dimensions of ∅21 × 33 mm3 was grown successfully by Czochralski method for the first time. Its spectral properties including polarized absorption spectra, polarized fluorescence spectra, excitation spectrum and fluorescence decay curves were investigated in detail. The absorption cross-sections at around 573 nm corresponding to the 4A2 → 4T2 transition of Cr3+ ions are 4.75 × 10−20 and 2.56 × 10−20 cm2 for σ- and π-polarizations, respectively. The excitation spectrum shows two broad and intense absorption bands at about 390 nm and 570 nm, which are associated with the 4A2 → 4T1 and 4A2 → 4T2 transitions of Cr3+ ions, respectively. The emission band with peak at around 744 nm is ascribed to the 2E → 4A2 transition of Cr3+ ions, with the emission cross-sections of 5.55 × 10−22 and 5.41 × 10−22 cm2 for σ- and π-polarizations, respectively. The fluorescence lifetime is 4.35 ms at room temperature. The Dq/B value is 2.72, which means that Cr3+ ions occupy the lattice sites with strong crystal field strength. The results show that Cr3+:CaGdAlO4 crystal can be regarded as a potential laser gain medium.