激光二极管抽运Tm:YAP晶体实验研究

简要阐述2 μm激光光源的广泛应用需求,分析掺铥铝酸钇(Tm:YAP)晶体的能级结构和吸收光谱特性,报道了采用激光二极管(LD)端面抽运Tm:YAP晶体的方式,实现室温下2 μm激光的高效输出。在激光二极管输出功率为19 W时, 2 μm连续激光输出功率为6.5 W,光光转换效率达34％,斜率效率为47.5％。经过声光(AO)Q开关进行调制后,在重复频率10 kHz下,获得5.4 W的动态激光输出,激光单脉冲宽度为70 ns,激光二极管输出功率到2 μm激光动态输出功率的转换效率为28％,斜率效率为42％。通过实验验证了激光二极管端面抽运Tm:YAP晶体在室温下高效输出的特性。     

利用窄得-奥菲特理论研究Tm:Lu2SiO5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.     

Size dependence of up-conversion luminescence of NaYF₄:Yb³⁺/Tm³⁺

Tm3+/Yb3+ codoped NaYF4 microcrystals were synthesized using a hydrothermal method.The bright upconversion light was observed under 980 nm excitation.The upconversion luminescence was systematically investigated at different Yb3+ concentrations and different reaction temperatures and time.The sample with 60% Yb3+ concentration and reacting at 180 oC for 24 h possessed the highest luminescent efficiency.The higher luminescent efficiency was contributed to a large surface area.The large surface area induced the large vibration mode by absorbed H2O and CO2.The larger vibration mode could enhance the energy transfer efficiency from the excited Yb3+ to Tm3+ by the process of phonon assisted energy transfer.     

Tm:YAP晶体生长及光谱特性研究

采用提拉法生长了掺杂浓度分别为4、8与10at%的Tm:YAP晶体. 测定了Tm³⁺在YAP基质中的分凝系数为0.88. 采用同步辐射的方法研究了Tm:YAP晶体的生长条纹和结构应力缺陷. 晶体的吸收峰位于694和795nm; 荧光谱峰值在2.0μm附近, 因此Tm:YAP晶体有望成为一种新型的适合LD泵浦的中红外激光材料.     

Enhanced microwave absorption properties of Fe73.5Cu1Nb3Si15.5B7 nanoflakes by moderate surface oxidization and rotational orientation in composites

Fe_73.5Cu₁Nb₃Si_15.5B₇ nanoflakes were fabricated by ball milling the annealed ribbons. The microwave absorption properties of Fe_73.5Cu₁Nb₃Si_15.5B₇ nanoflakes were improved by moderate surface oxidization and rotational orientation in composites. As for the oxide-coated nanoflakes composite, the permittivity decreased distinctly and the permeability maintained the initial value compared with the as-milled nanoflakes composite. Through rotational orientation, the lower permittivity and higher permeability were obtained, and consequently the microwave absorption properties were improved obviously. The minimum reflectivity for the absorber of the oriented composites with 35 vol% oxide-coated nanoflakes could reach −46.4 dB at 1.31 GHz with the thickness of 4.2 mm.     

相位掩模法红外飞秒激光刻写光纤光栅技术

掺Tm3+光纤激光器在工业、医疗、科技及军事领域具有重要应用前景.光纤布拉格光栅(FBG)是构成光纤激光器的重要元件.但掺Tm3+光纤不具备光敏性,利用紫外脉冲激光很难在其中刻写FBG,即使采用增敏技术提高其光敏性,获得的FBG的折射率调制量也很小,尚不能满足应用要求,阻碍了掺Tm3+光纤激光器全光纤化的发展.以相位掩...     

Tm脉冲激光器泵浦的中红外固体激光器

介绍了Tm:YAP脉冲激光器泵浦的中红外固体激光器.首先介绍了Tm脉冲激光器,由实验分析,对YAP固体激光器腔型结构进行优化,确定了适合泵浦ZGPOPO的YAP激光器腔型,得到较理想的2 μm脉冲激光输出.中红外固体激光器由优化后的Tm:YAP激光器泵浦ZGP光学参量振荡器(OPO)组成,最终得到输出功率达瓦级以上的3...     

A speed measurement system utilizing an injection-seeded Tm:YAG laser

A speed measurement system utilizing a stable single frequency Q-switched Tm:YAG laser was presented in this study.The maximum pulse energy of the laser was 2.38 mJ with the pulse repetition rate of 10...     

Investigation of 2.9 μm luminescence properties and energy transfer in Tm~(3+)/Dy~(3+) co-doped chalcohalide glasses

A series of chalcohalide glasses based on the composition of 0.9(Ge30Ga5Se65)-0.1CsI with different Tm3+/Dy3+-codoped ions concentrations were synthesized by melt-quenching technique.The absorption spectra and 2.9 μm mid-infrared fluorescence spectra of glass samples under 800 nm laser excitation were measured.The results showed that Tm3+ was an efficient sensitizer,which could enhance the Dy3+: 2.9 μm fluorescence intensity significantly.The effective energy transfer between the two rare-earth ions were mainly attributed to the resonance energy transfer from Tm3+:3F4 to Dy3+:6H11/2 level.Emission cross section of 2.9 μm mid-infrared luminescence was also investigated according to Judd-Ofelt theory,σe=2.51×10–20 cm2.     

Hydrothermal synthesis of one dimensional GdV1-xPxO4 ： Tm nanomaterials and their luminescent properties

以乙二胺四乙酸（EDTA）为模板剂,采用水热法,成功地合成一系列具有较大长径比的一维GdV1-xPxO4∶Tm蓝色纳米荧光粉。利用X射线衍射仪、扫描电镜、荧光光谱仪对产物的相结构、形貌和发光性能进行了分析。结果表明所得产物均具有明显的一维特征,随P含量的增加,产物的长径比增加,纳米棒逐渐变细。产物在未经焙烧的条件下,在278nm波长紫外光激发下发出强度较高的波长为478nm的明亮蓝光,掺P摩尔比,即x=0.4时,所得产物的发光强度最好。