A Q-switched distributed Bragg reflector fiber laser using a graphene passive saturable absorber is proposed in a cavity consisting of a fiber Bragg grating and Faraday rotator mirror as end mirrors, together with a h...A Q-switched distributed Bragg reflector fiber laser using a graphene passive saturable absorber is proposed in a cavity consisting of a fiber Bragg grating and Faraday rotator mirror as end mirrors, together with a highly doped erbium-doped fiber as a gain source. The laser has a Q-switched threshold of about 28 mW and a tunable repetition rate of 10.4-18.0 kHz with varying pump power. The shortest pulse width obtained from the system is 3.7 its, with a maximum pulse energy and peak power of 22.2 nJ and 3.4 mW, respectively.展开更多
利用连续流平面型光腔动力学模型对NCl(a1Δ)/I 激光体系进行了模拟计算,探讨了温度在300 K 时NCl(a1Δ)自猝灭对NCl(a1Δ)/I激光能量提取的影响。计算结果表明,NCl(a1Δ)自猝灭反应对光腔位置的选取、功率密度沿流动方向的分布和总输...利用连续流平面型光腔动力学模型对NCl(a1Δ)/I 激光体系进行了模拟计算,探讨了温度在300 K 时NCl(a1Δ)自猝灭对NCl(a1Δ)/I激光能量提取的影响。计算结果表明,NCl(a1Δ)自猝灭反应对光腔位置的选取、功率密度沿流动方向的分布和总输出功率都有较大的影响。其中,光腔位置的可选范围大大缩短,在较小的初始HI粒子数密度和适当的输出镜反射率下总输出功率大幅度降低,而随着HI粒子数密度的增加,NCl(a1Δ)自猝灭对总输出功率的影响逐渐减小。展开更多
Let G be a graph, and g, f ： V（G）→Z＋ with g（x） 〈 f（x） for each x ∈ V（G）. We say that G admits all fractional （g, f）-factors if G contains an fractional r-factor for every r ： V（G）→ Z＋ with g（x） ...Let G be a graph, and g, f ： V（G）→Z＋ with g（x） 〈 f（x） for each x ∈ V（G）. We say that G admits all fractional （g, f）-factors if G contains an fractional r-factor for every r ： V（G）→ Z＋ with g（x） ≤ r（x） ≤ f（x） for any x ∈ V（G）. Let H be a subgraph of G. We say that G has all fractional （g, f）-factors excluding H if for every r ： V（G） → Z＋ with g（x） ≤ r（x） ≤ f（x） for all x ∈ V（G）, G has a fractional r-factor Fh such that E（H） ∩ E（Fh） = Ф, where h ： E（G） → [0, 1] is a function. In this paper, we show a characterization for the existence of all fractional （g, f）-factors excluding H and obtain two sufficient conditions for a graph to have all fractional （g, f）-factors excluding H.展开更多
基金supported by the Ministry of Higher Education/University of Malaya(Nos.UM.C/HIR/MOHE/SC/01 and UPGP2012)
文摘A Q-switched distributed Bragg reflector fiber laser using a graphene passive saturable absorber is proposed in a cavity consisting of a fiber Bragg grating and Faraday rotator mirror as end mirrors, together with a highly doped erbium-doped fiber as a gain source. The laser has a Q-switched threshold of about 28 mW and a tunable repetition rate of 10.4-18.0 kHz with varying pump power. The shortest pulse width obtained from the system is 3.7 its, with a maximum pulse energy and peak power of 22.2 nJ and 3.4 mW, respectively.
文摘利用连续流平面型光腔动力学模型对NCl(a1Δ)/I 激光体系进行了模拟计算,探讨了温度在300 K 时NCl(a1Δ)自猝灭对NCl(a1Δ)/I激光能量提取的影响。计算结果表明,NCl(a1Δ)自猝灭反应对光腔位置的选取、功率密度沿流动方向的分布和总输出功率都有较大的影响。其中,光腔位置的可选范围大大缩短,在较小的初始HI粒子数密度和适当的输出镜反射率下总输出功率大幅度降低,而随着HI粒子数密度的增加,NCl(a1Δ)自猝灭对总输出功率的影响逐渐减小。
基金supported by the National Natural Science Foundation of China(Grant No.11371009,11501256,61503160)sponsored by Six Big Talent Peak of Jiangsu Province(Grant No.JY–022)333 Project of Jiangsu Province
文摘Let G be a graph, and g, f ： V（G）→Z＋ with g（x） 〈 f（x） for each x ∈ V（G）. We say that G admits all fractional （g, f）-factors if G contains an fractional r-factor for every r ： V（G）→ Z＋ with g（x） ≤ r（x） ≤ f（x） for any x ∈ V（G）. Let H be a subgraph of G. We say that G has all fractional （g, f）-factors excluding H if for every r ： V（G） → Z＋ with g（x） ≤ r（x） ≤ f（x） for all x ∈ V（G）, G has a fractional r-factor Fh such that E（H） ∩ E（Fh） = Ф, where h ： E（G） → [0, 1] is a function. In this paper, we show a characterization for the existence of all fractional （g, f）-factors excluding H and obtain two sufficient conditions for a graph to have all fractional （g, f）-factors excluding H.
