Plasma channel formed by ultraviolet laser pulses at 193 nm in air

The propagation of picosecond deep ultraviolet laser pulse at wavelength of 193 nm in air is numerically investigated. Long plasma channel can be formed due to the competition between Kerr self-focusing and ionization induced defocusing. The plasma channel with electron density of above 10^13/cm^3 can be formed over 70 m by 50-ps, 20-mJ laser pulses. The fluctuation of laser intensity and electron density inside ultraviolet （UV） plasma channel is significantly lower UV laser by air is considered in the simulation and it the limit of the length of plasma channel. than that of infrared pulse. The linear absorption of is shown that the linear absorption is important for the limit of the length of plasma channel.     

飞秒激光直写光量子逻辑门

量子比特在同一时刻可处于所有可能状态上的叠加特性使得量子计算机具有天然的并行计算能力,在处理某些特定问题时具有超越经典计算机的明显优势.飞秒激光直写技术因其具有单步骤高效加工真三维光波导回路的能力,在制备通用型集成光量子计算机的基本单元—量子逻辑门中发挥着越来越重要的作用.本文综述了飞秒激光直写由定向耦合器构成的光量子比特逻辑门的进展.主要包括定向耦合器的功能、构成、直写和性能表征,集成波片、哈达玛门和泡利交换门等单量子比特逻辑门、受控非门和受控相位门等两量子比特逻辑门的直写加工,并对飞秒激光加工三量子比特逻辑门进行了展望.     

飞秒时间分辨近场光学系统实现及其应用

结合飞秒光脉冲和近场光学显微镜，成功实现了飞秒时间分辨近场光学系统.系统通过高频声光调制和差频锁相探测，极大提高了信噪比并消除了抽运、探测光本底信号，从而在收集模式下测得了飞秒时间分辨的透射光微弱信号变化.同时获得了80nm的空间分辨和小于200fs的时间分辨测量.利用该实验系统，研究了金纳米结构的热电子弛豫动力学过程，观察到不同位置间热电子弛豫动力学的差异. 关键词： 飞秒近场 扫描近场光学显微镜 飞秒光脉冲 金纳米颗粒     

Large and Ultrafast Third-Order Nonlinear Optical Properties of Ge-S Based Chalcogenide Glasses

We report ultrafast third-order nonlinear optical （NLO） properties of several chalcogenide glasses GeSx （x = 1.8, 2.0, 2.5） measured by femtosecond time-resolved optical Kerr gate technique at 82Ohm. The third-order nonlinear susceptibility of GeS1.8 glass is determined to be as large as 1.41 ×10^-12 esu, which is the maximum value of the third order nonlinear susceptibility Х^（3） for the three compositions investigated. The symmetric Gauss profiles of optical Kerr signals reveal the nature of ultrafast nonlinear response of these samples, which are originated from the ultrafast polarization of the electron clouds. By detailed microstructural analysis of these glasses based on the chain-crossing model （CCM） and the random-covalent-network model （RCNM）, it can be concluded that Х^（3） value of GeSx glasses can be enhanced greatly by S-S covalent bonds or S3 Ge-GeS3 ethane-l＆e units.     

C60高聚物复合固体材料的反饱和吸收过程研究

本文报导了新型材料C_(60)α-甲基苯乙烯/苯乙烯共聚物薄板的制作,并利用530nm,10ns激光研究此固体材料的激光透过特性.观测到反饱和吸收过程,即实现了光限制效应.     

光学简并三波混频中的量子非破坏测量

运用半经典量子理论方法建立了光学简并三波混频在两输入场均不为零的情况下的理论模型 ,讨论了在两输入场均不为零时系统的动力学行为以及相应的量子非破坏测量 (QND)特性。研究结果表明 ,该系统的最佳量子非破坏测量工作点与以往的情况不同 ,不是出现在非线性共振点处而是在双稳转变点     

低玻璃化转变温度的光折变聚合物中光敏剂作用研究

通过对光敏剂C₆₀含量不同的低玻璃化转变温度的光折变聚合物聚乙烯咔唑掺杂2,5-二甲基-4-(4′-硝基苯偶氮基)苯甲醚、N-乙基咔唑和C₆₀的空间相移角和二波耦合系数的测量,研究了光敏剂在此类光折变聚合物中的作用- 关键词：     

双波长飞秒激光器运转特性的数值分析

本文采用有限差分方法对双波长飞秒激光器的运转特性进行了数值分析,得到了不同腔内群速弥散量下交叉锁模脉冲的数值解.结果表明,在双光束谐振腔内,由于飞秒激光的相互作用、平衡增益竞争、补偿腔内的群速弥散,就能够获得最佳的双波长飞秒激光器运转.     

Low temperature enhancement of alignment-induced spectral broadening of femtosecond laser pulses

The propagation of femtosecond laser pulses in N2-filled hollow fibers is studied both theoretically and experimentally. The laser pulse aligns the N2 molecules and changes the refractive index, which meanwhile modulates the spectrum of the pulse in turn. The dependence of the spectral modulation on the gas temperature is investigated. We find that both spectral broadening and frequency red-shift are enhanced at low temperature. The degree of enhancement is found to be dependent on the pulse duration. Based on our findings, we propose a method for femtosecond pulse spectral broadening and few-cycle pulse generation via the molecular alignment.     

基于金颗粒自组装烷基硫醇为缓冲层的有机太阳能电池

有机活性层和无机电极的界面修饰影响到有机太阳能电池性能。本文引入金纳米颗粒自组装烷基硫醇,改善有机/无机的界面。制备“ITO/金颗粒-硫醇自组装缓冲层/聚3-己基噻吩(P3HT)∶[6,6]-苯基-C61-丁酸甲酯(PCBM)/LiF/Al电极”结构的器件。自组装硫醇防止了因金颗粒与活性层直接接触导致的激子猝灭效应。我们研究了金纳米颗粒自组装不同链长的烷基硫醇对器件性能的影响,烷基硫醇的烷基链越长,硫醇对金颗粒的覆盖性越好,器件的短路电流越高。金纳米颗粒自组装十二烷基硫醇,短路电流J_SC由5.19 mA·cm-2提升到6.24 mA·cm-2,提高了20%。