We demonstrate continuous wave (CW) room temperature laser operation of the monoclinic Ho(3+)-doped KLu(WO(4))(2) crystal using a diode-pumped Tm(3+):KLu(WO(4))(2) laser for in-band pumping. The ...slope efficiency achieved amounts to ~55% with respect to the absorbed power and the maximum output power of 648 mW is generated at 2078 nm.
We report the room-temperature spectroscopic properties and continuous-wave laser operation of a new disordered crystal, Yb:Ca(3)(NbGa)(2-x)Ga(3)O(12). The peak absorption cross section is ...3.3x10(-20) cm(2) at 973.5 nm; the emission band important for laser action is centered at 1028 nm with a peak cross section of 2.5x10(-20) cm(2). By diode end pumping, an output power of 1.9 W was achieved with a slope efficiency of 28.5%.
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•CuO-NPs have been synthesized by green synthesis method using prickly pear peel extract.•The obtained powder have been characterized by powder-X-ray diffraction, FT-IR, SEM-EDX and ...TEM.•CuO-NPs are spherical shape with mean size 40 nm.•Excellent catalytic performance of the reduction of 4-NP to 4-AP.•A Mechanism of the reduction of 4-NP was proposed.
In this work, a rapid and green synthesis of copper oxide nanoparticles was developed using aqueous extract of prickly pear peel. The obtained CuO nanoparticles were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDX). The XRD result showed that CuO nanoparticles crystallize in the C 2/c monoclinic space group and confirmed their purity by refinement of the pattern. The FTIR measurements indicated that the different phytochemicals present in prickly pear peels extract are indispensable for the synthesis of CuO nanoparticles. The UV–visible analysis reported the surface Plasmon resonance band at 284 nm. The SEM and TEM analysis also confirmed that the synthesized nanoparticles had spherical morphology with uniform symmetry and displayed a particle in a 20–40 nm range size. The EDX spectrum and mapping proved the purity of CuO with Cu and O occurrence. Afterward, the catalytic activity of the synthesized catalyst was tested for the reduction of 4-nitrophenol (4-NP) in the presence of sodium borohydride in an aqueous media. Moreover, the catalyst showed high durability during several cycles.
We report the formation of two-dimensional disordered arrays of poly(methyl)methacrylate (PMMA) microcolumns with embedded single size distribution of Lu
0.990
Er
0.520
Yb
0
.
490
nanocrystals, ...(Er,Yb):Lu
2
O
3
, using a disordered porous silicon template. The cubic (Er,Yb):Lu
2
O
3
nanocrystals, which crystallize into the cubic system with
Ia
3
¯
space group, were synthesized using the modified Pechini method. Electronic microscopic techniques were used to study the distribution of the nanocrystals in the PMMA columns. Cathodoluminescence was used to observe the visible luminescence of the particles. Red emission attributed to
4
F
9/2
→
4
I
15/2
erbium transition is predominant in these new composites.
Ho:Y2O3 and Ho:Y3Al5O12 transparent ceramics are fabricated by vacuum sintering at 1780 °C for 20 h from laser-ablated nanopowders (Ho:Y2O3 and Ho:Y2O3 + Al2O3) using ZrO2 and TEOS as sintering aids, ...respectively. The sesquioxide ceramic exhibits smaller grain size (∼5.4 μm), smaller content of pores (down to 6 ppm) and higher optical transmission (up to 82.2% at ∼1 μm) than the garnet one. A detailed comparative spectroscopic study of the two ceramics is performed. For the 5I7 → 5I8 Ho3+ transition, the maximum stimulated-emission cross-sections and the luminescence lifetimes are σSE = 0.57 × 10−20 cm2 at 2087.1 nm and τlum = 10.92 ms (for the Ho:Y2O3 ceramic) and σSE = 1.70 × 10−20 cm2 at 2090.8 nm and τlum = 7.04 ms (for the Ho:Y3Al5O12 one) The rates of multiphonon relaxation are determined for both ceramics. For the Ho:Y2O3 ceramic, they do not exceed those for single-crystals. The crystal-field splitting of Ho3+ multiplets (5I7 and 5I8) is determined at 12 K and analyzed using the barycenter plot. Due to its broadband emission properties, the Ho:Y2O3 ceramic is suitable for mode-locked lasers emitting above 2 μm.
•0.94 at.% Ho3+-doped Y2O3 and Y3Al5O12 transparent ceramics.•Vacuum sintering at 1780 °C from laser-ablated nanopowders using ZrO2 and TEOS.•A detailed comparative study of microstructure, optical and spectroscopic properties.•The rates of multiphonon relaxation are determined for both ceramics.•The crystal-field splitting of Ho3+ ions is analyzed using the barycenter plot.
A Tm,Ho:CALGO laser passively mode-locked by a GaSb-based SESAM generated pulses as short as 52 fs at a central wavelength of 2015 nm with a broad spectral bandwidth of 82 nm (full width at half ...maximum) owing to the combined gain profiles of both dopants for σ-polarized light. The average output power reached 376 mW at a repetition rate of 85.65 MHz. In the continuous-wave regime, the laser was power scaled up to 1.01 W at 2080.6 nm with a slope efficiency of 32.0%, a laser threshold of 155 mW and π-polarized emission. Polarized spectroscopic properties of Ho
ions in singly doped and codoped CALGO crystals were revisited to explain the observed laser performance.
We report on the first sub-100 fs mode-locked laser operation of a Tm 3+ -doped disordered calcium lithium tantalum gallium garnet (Tm:CLTGG) crystal. Soliton mode-locking was initiated and ...stabilized by a transmission-type single-walled carbon nanotube saturable absorber. Pulses as short as 69 fs were achieved at a central wavelength of 2010.4 nm with an average power of 28 mW at a pulse repetition rate of ∼87.7 MHz. In the sub-100 fs regime, the maximum average output power amounted to 103 mW.
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