Efficient diode-pumped Tm : YALO(3) laser with a pump recycling scheme

By using a pump recycling configuration, the maximum power of 8.1 W in the wavelength range 1.935-1.938 mu m is generated by a 5-mm long Tm:YAlO3 (4 at. %) laser operating at 18 degrees C with a pump power of 24 W. The highest slope efficiency of 42% is attained, and the pump quantum efficiency is up to 100%. The Tm:YAlO3 laser is employed as a pumping source of singly-doped Ho(l%):GdVO4 laser operating at room temperature, in which continuous wave output power of greater than 0.2 W at 2.05 mu m is achieved with a slope efficiency of 9%.

室温下光纤耦合二极管泵浦Tm：YAP激光器

为实现室温下小型化、高效率的1.9μm激光输出,采用793.5 nm激光二极管泵浦Tm：YAP晶体,晶体采用热电制冷及风冷的方式控制在18℃,采用1∶1的聚焦耦系统,获得功率为2.2 W、中心波长为1928 nm的激光输出,光光转换效率为31%,斜率效率达41%。对影响激光输出的耦合输出率、腔型、腔长、晶体工作温度等因素进行了实验分析,实验结果表明：输出功率的变化与温度基本成线性关系,当增加激光谐振腔长时,由于高阶模式损耗加大以及晶体热透镜效应的加重导致腔内损耗加大,输出功率和斜率效率都有所下降。

Judd-Ofelt analysis of spectra and experimental evaluation of laser performance of Tm3+ doped Lu2SiO5 crystal

This paper reports that the TM3+:Lu2SiO5 (Tm:LSO) crystal is grown by Czochralski technique. The room-temperature absorption spectra of Tm:LSO crystal are measured on a b-cut sample with 4 at.% thulium. According to the obtained Judd-Ofelt intensity parameters Omega(2)=9.3155 x 10(-20) cm(2), Omega(4)=8.4103 x 10(-20) cm(2), Omega(6)=1.5908 x 10(-20) cm(2), the fluorescence lifetime is calculated to be 2.03 ms for F-3(4) -> H-3(6) transition, and the integrated emission cross section is 5.81 x 10(-18) cm(2). Room-temperature laser action near 2 mu m under diode pumping is experimentally evaluated in Tm:LSO. An optical-optical conversion efficiency of 9.1% and a slope efficiency of 16.2% are obtained with continuous-wave maximum output power of 0.67 W. The emission wavelengths of Tm:LSO laser are centred around 2.06 mu m with spectral bandwidth of similar to 13.6 nm.

利用窄得-奥菲特理论研究Tm:Lu_2SiO_5晶体的光谱特性

采用丘克拉斯基(Czochralski)技术生长了掺铥硅酸镥(Tm∶Lu2SiO5,Tm∶LSO)晶体;测量了LSO晶体在室温下的非偏振吸收光谱和非偏振荧光光谱;利用窄得-奥菲特(Judd-Ofelt)理论计算了Tm∶LSO晶体的窄得-奥菲特强度参数、振子强度、自发辐射概率、辐射寿命、积分吸收截面和积分发射截面.Tm∶LSO晶体的强度参数为Ω2=9.1355×10-20cm2,Ω4=8.4103×10-20cm2,Ω6=1.5908×10-20cm2;Tm∶LSO晶体在1.9μm附近有明显的发射峰(3F4→3H6跃迁),相应的辐射寿命为2.03 ms,积分发射截面为5.81×10-18cm2,半峰全宽(FWHM)为250 nm.用Tm∶LSO晶体在77 K温度下实现了激光运转.利用792 nm的激光二极管(LD)作为抽运源,获得中心波长为1960 nm的激光输出,抽运阈值为2.13 kW/cm2.

Diode-pumped Q-switched Tm:YAP laser with a pump recycling scheme

We reported on a diode end-pumped AO Q-switched Tm:YAP laser at 1937 nm. The average output power was 3.9 W, with a slope efficiency of 29.4% and optical-optical conversion efficiency of 21.6% at a 5-kHz repetition rate. The temperature dependency of the output power and the pulse width at different repetition rates were investigated in details.

Judd-Oflet analysis of spectrum and laser performance of Ho:YAP crystal end-pumped by 1.91-mu m Tm:YLF laser

The Ho:YAP crystal is grown by the Czochralski technique. The room-temperature polarized absorption spectra of Ho:YAP crystal was measured on a c-cut sample with 1 at% holmium. According to the obtained Judd-Ofelt intensity parameters Omega(2) = 1.42 x 10(-20) cm(2), Omega(4) = 2.92 x 10(-20) cm(2), and Omega(6) = 1.71 x 10(-20) cm(2), this paper calculated the fluorescence lifetime to be 6 ms for I-5(7) -> I-5(8) transition, and the integrated emission cross section to be 2.24 x 10(-18) cm(2). It investigates the room-temperature Ho:YAP laser end-pumped by a 1.91-mu m Tm:YLF laser. The maximum output power was 4.1 W when the incident 1.91-mu m pump power was 14.4W. The slope efficiency is 40.8%, corresponding to an optical-to-optical conversion efficiency of 28.4%. The Ho:YAP output wavelength was centred at 2118 nm with full width at half maximum of about 0.8 nm.

2 to 3 μm Raman-soliton continuum enabled by a nanotube mode-locked Tm-doped MOPFA

We demonstrate a Raman-soliton continuum extending from 2 to 3 μm, in a highly germanium-doped silica-clad fiber, pumped by a nanotube mode-locked thulium-doped fiber system delivering 12 kW sub-picosecond pulses at 1.95 μm. © OSA 2013.

Four New Lanthanide-Nitronyl Nitroxide (Ln(III)=Pr-III, Sm-III, Eu-III, Tm-III) Complexes and a Tb-III Complex Exhibiting Single-Molecule Magnet Behavior

Five new complexes based on rare-earth-radical [Ln(hfac)(3)(NIT-5-Br-3py)](2) (Ln=Pr (1), Sm (2), Eu (3), Tb (4), Tm (5); hfac = hexafluoroacetylacetonate; NIT-5-Br-3py = 2-(4,4,5,5-tetramethyl-3-oxylimidazoline-1-oxide)-5-bromo-3-pyridine) have been synthesized and characterized by X-ray crystal diffraction. The single-crystal structures show that these complexes have similar structures, in which a NIT-5-Br-3py molecule acts as a bridging ligand linking two Ln(III) ions through the oxygen atom of the N-O group and nitrogen atom from the pyridine ring to form a four-spin system. Both static and dynamic magnetic properties were measured for complex 4, which exhibits single-molecule magnetism behavior.

Formação de um rebanho de corte utilizando novilhas cobertas aos 15 e 18 meses de idade.

Este trabalho visa orientar os produtores e técnicos que têm interesse em formar novos rebanhos com fêmeas acasaladas aos 15 ou 18 meses de idade. Tais orientações, no entanto, só serão válidas quando outros aspectos de manejo forem também observados, tais como: controle sanitário eficiente, estação de monta bem definida, controle adequado da qualidade e quantidade de pastagem disponível, etc.

In vitro testing of Advanced JAX (TM) Bone Void Filler System: species differences in the response of bone marrow stromal cells to beta tri-calcium phosphate and carboxymethylcellulose gel

The Advanced JAX (TM) Bone Void Filler System (AJBVFS) is a novel bone graft material manufactured by Smith and Nephew Orthopaedics Ltd. and comprises beta tri-calcium phosphate granules with carboxymethylcellulose (CMC) gel as a handling agent. This study investigated the potential, in vitro, of the AJBVFS to function as a delivery system for cell therapy to enhance healing of bone defects. The attachment of rabbit bone marrow stromal cells (rbBMSCs), human BMSCs (hBMSCs) and human bone-derived cells (hBDCs) to JAX (TM) granules and the effect of CMC gel on cell proliferation and differentiation were investigated. There were slight species differences in the number and morphology of cells attached on the JAX (TM) granules with less rbBMSC attachment than human. All cells tolerated the presence of CMC gel and a reduction in cell number was only seen after longer exposure to higher gel concentrations. Low concentrations of CMC gel enhanced proliferation, alkaline phosphatase (ALP) expression and ALP activity in human cells but had no effect on rbBMSC. This study suggests that AJBVFS is an appropriate scaffold for the delivery of osteogenic cells and the addition of CMC gel as a handling agent promotes osteogenic proliferation and differentiation and is therefore likely to encourage bone healing.

Phenotype MicroArray (TM) in the metabolic characterisation of Salmonella serotypes Agona, Enteritidis, Give, Hvittingfoss, Infantis, Newport and Typhimurium

The Phenotype MicroArray (TM) (PM) technology was used to study the metabolic characteristics of 29 Salmonella strains belonging to seven serotypes of S. enterica spp. enterica. Strains of serotypes Typhimurium (six strains among definite phage types DTs 1, 40 and 104) and Agona (two strains) were tested for 949 substrates, Enteritidis (six strains of phage type PT1), Give, Hvittingfoss, Infantis and Newport strains (two of each) were tested for 190 substrates and seven other Agona strains for 95 substrates. The strains represented 18 genotypes in pulsed-field gel electrophoresis (PFGE). Among 949 substrates, 18 were identified that could be used to differentiate between the strains of those seven serotypes or within a single serotype. Unique metabolic differences between the Finnish endemic Typhimurium DT1 and Agona strains were detected, for example, in the metabolism of d-tagatose, d-galactonic acid gamma-lactone and l-proline as a carbon source. Thus, the PM technique is a useful tool for identifying potential differential markers on a metabolic basis that could be used for epidemiological surveillance.