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A series of high quality x%Pr3+:BaF2 (x = 0.6, 1, 2); (1%Pr3+, 2%Na+):BaF2; (1%Pr3+, y%Ca2+):BaF2 (y = 3, 5) and (0.6%Pr3+, 10%R3+):BaF2 (R = Y, Lu, Gd) crystals were grown by temperature gradient technique (TGT). The Raman spectra, absorption spectra, fluorescence spectra, and fluorescence decay lifetime were measured. XRD patterns indicate that the as-synthesized samples are pure BaF2 phase. The absorption cross-section of Pr3+ ions in the BaF2 matrix can be greatly improved by co-doping R3+ ions, while improvement by Na+ and Ca2+ ions is marginal. The fluorescence characteristic of Pr3+ ions can be effectively regulated by co-doping Na+, Ca2+, R3+ (R = Y, Lu, Gd) ions of different valence states. When R3+ ions are introduced, the fluorescence spectra show the strongest orange emission and the CIE chromaticity coordinates of Pr3+ ions are also in the orange region. When single-doped Pr3+ ions and Na+ or Ca2+ ions are introduced, the fluorescence lifetime of the 3P0 level is double exponential decay, and the short lifetime is the main proportion. However, the fluorescence centers tend to homogeneous and stable by R3+ ions co-doping and the fluorescence lifetime exhibits single-exponential decay, which is fitted to 49.7 μs, 47.8 μs and 49.6 μs of (0.6%Pr3+, 10%R3+):BaF2 (R = Y, Lu, Gd), respectively. All the results show that (Pr3+, Gd3+):BaF2 and (Pr3+, Na+):BaF2 are excellent laser gain media for high-efficiency orange and red laser operation. [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]

A Kerr-lens mode-locked laser based on a Yb 3+ -doped disordered gadolinium scandate (Yb:GdScO 3 ) crystal is reported for the first time, to the best of our knowledge. The crystal with the perovskite structure was grown using the Czochralski method, and its room temperature (RT) and low temperature (LT) spectra were also investigated. Due to the crystal's multisite structure (Gd 3+ /Sc 3+ site), Yb:GdScO 3 offers broad and intense polarized emission spectra in the near-infrared range (975-1075 nm). The stimulated emission cross section σSE is 0.46 × 10 -20 cm 2 at 1000 nm with an emission band width of 75.7 nm for E // b polarization. The continuous wave (CW) laser was operated pumped by a 976 nm fiber-coupled LD laser, resulting in a maximum output power of 8.74 W with a slope efficiency of 76.1% was obtained. Additionally, a pulses as short as 74 fs are generated at ∼1061.7 nm via Kerr-lens mode-locking. The average output power amounts to 32 mW at a pulse repetition rate of 101.4 MHz. All results indicate Yb:GdScO 3 a promising candidate for 1 µm ultrashort laser.

A novel, to the best of our knowledge, Tm,Ho:GdScO 3 crystal grown using the Czochralski method was investigated for its polarized spectroscopic properties and laser performance in both tunable continuous-wave (CW) and mode-locked regimes. The crystal's multisite structure (Gd 3+ /Sc 3+ site) and Tm 3+ /Ho 3+ dopants contributed to spectral broadening, enabling a tunable laser operation from 1914 to 2125 nm (with a broad range of 215 nm). Additionally, a pulse duration of 72 fs was achieved for E || b polarization. These results demonstrate the potential of the Tm,Ho:GdScO 3 perovskite crystal as a promising gain material for ultrafast lasers operating around 2 µm.

The spectroscopic properties and tunable laser performances of the orthorhombic perovskite Tm:GdScO 3 crystal grown by the Czochralski method are comparatively studied for polarization along different crystallographic axes. The polarized emission spectrum of Tm:GdScO 3 along the b-axis exhibits, to the best of our knowledge, the broadest bandwidth among all the single Tm 3+ -doped bulk gain media, indicating the strong inhomogeneous line broadening of Tm 3+ ions in GdScO 3 and thus leads to a broad and smooth gain spectrum. Tunable laser operation with a tuning range as broad as 321 nm from 1824 nm to 2145 nm is achieved, which indicates its potential for few-optical-cycle pulse generation in the 2-µm spectral range.

Pulses as short as 44 fs (6 optical cycles) with a spectral width of 120 nm are generated from a mode-locked solid-state laser near 2 µm employing an orthorhombic Tm:GdScO 3 perovskite crystal. The average power amounts to 188 mW at a repetition rate of ∼77.6 MHz. The strong inhomogeneous line broadening in GdScO 3 suggests optimum conditions for few-optical-cycle pulse generation of rare-earth ion doped GdScO 3 bulk lasers.

Deoxynivalenol (DON) and fumonisin B 1 (FB 1 ), as a group of highly toxic secondary metabolites, have become a potential source of water environmental pollutants. To minimize two mycotoxins exposure to consumers, a dual lateral flow immunoassay (LFIA) integrated with the smartphone was reported for simultaneous and quantitative detection of DON and FB 1 in the water environment. The significantly improved sensitivity was contributed to a smartphone-based device with the ability to image and analyze results. Under optimized conditions, the detection limits of DON and FB 1 were calculated to be 3.46 and 2.65 ng/mL, which were approximately 25 and 10 folds lower than those of the visual detection of the LFIA. This method showed good specificity and a good dynamic linear detection for DON and FB 1 . The recoveries of DON and FB 1 were evaluated by the spiked lake water, river water, and pond water, ranging from 92.47% to 106.2% with the relative standard deviation under 9.13%. Moreover, the results of the developed LFIA showed a high correlation with enzyme-linked immunosorbent assay (ELISA) results, with a correlation coefficient of 0.999 for DON and 0.996 for FB 1 , respectively. To sum up, the developed LFIA provides a promising platform for sensitive, simultaneous, quantitative, and on-site detection of DON and FB 1 in the water environment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022. Published by Elsevier B.V.)