飞秒激光双光子荧光显微系统的构建与应用

为进行双光子荧光显微成像研究,搭建了一套飞秒激光光源双光子荧光显微成像系统.对超短脉冲锁模激光器的成像优势、双光子激励饱和功率及系统分辨率进行了理论推导,利用飞秒激光器、显微镜、数据采集设备与控制装置及扫描控制软件搭建了显微成像系统,并对Rhodamine B样品进行双光子荧光显微成像实验.结果表明:相同条件下,超短脉冲锁模激光器的双光子荧光产率为连续光输出激光器的105倍;采用UPLSAPO60XO型物镜时,双光子激励饱和功率为50 m W,理论横向和轴向分辨率为303 nm与727 nm;该系统具有显微成像能力,且实际横向分辨率小于3μm.     

咔唑衍生物及8-羟基喹啉与ZnS纳米粒子复合及光学性能研究

采用微乳液的方法制备了平均粒径为85 nm的ZnS纳米粉体。主要测试了咔唑衍生物及8-羟基喹啉与ZnS纳米粒子复合后在四氢呋喃、N,N-二甲基甲酰胺中的单/双光子荧光特性。研究发现咔唑衍生物的双光子荧光强度较未加入纳米ZnS时只有提高不足20%,而8-羟基喹啉与纳米ZnS复合后得到了一种新的发光体系,其荧光强度可提高2~4倍,同时荧光发射峰出现了较大程度的红移,其红移达116 nm。     

基于微型化双光子荧光显微镜的自由活动小鼠脊髓成像方法

脊髓作为连接大脑与周围神经系统的桥梁,在躯体感觉和运动过程中发挥着编码大脑下行指令和外周输入信号的重要作用。通过光学成像方法,实时解析动物行为和脊髓神经活动之间的关系仍是神经科学研究的一大挑战。该文借助微型化双光子荧光显微镜,开发出一套适于自由活动小鼠的脊髓神经细胞活体成像方法,并通过对脊髓前动脉血管的成像,评估了该方法在无束缚环境中自由活动的动物自发行为和剧烈运动过程中的图像质量和成像稳定性。从物理层面解决了以往研究所面临的由于脊髓无规则运动导致的图像偏差和丢失等关键问题,实现了基于微型化双光子荧光显微镜的活体脊髓稳定成像。此外,利用该方法,还实现了小鼠脊髓背角浅层神经元活动中单个神经元钙信号的实时成像。这将为探究脊髓在躯体感觉和运动过程中神经元活动模式提供技术支持,对推动脊髓功能神经网络的研究具有重要意义。     

类Kerr媒质中双光子J-C模型场的压缩效应

研究类Ｋｅｒｒ媒质中双光子Ｊ－Ｃ模型腔场的压缩效应，揭示类Ｋｅｒｒ媒质对光场压缩 的影响．     

Femtosecond pulse width control in microscopy by two-photon absorption autocorrelation

A technique for both the measurement and the control of the pulse width at the focal point of a high-NA lens, based on two-photon absorption interferometric autocorrelation, is presented. The technique is applied to measuring the pulse broadening induced on a pulse propagating through a high-NA lens system for several objectives. It is known that the pulse width may increase by up to ?50% of its original value by propagation through an objective which has wide field compensation for spherical and chromatic aberrations. The two-photon absorption autocorrelation technique allows adjustment of the actual pulse width in the focus of a high-NA lens through pre-chirp compensation. The pulse width is shown to be almost independent of penetration depth into the sample, while the amplitude of the autocorrelation signal shows a strong decrease with depth. The ability to both measure and control the actual pulse width under strong focusing conditions is of direct importance to, among others, two-photon absorption imaging approaches.     

Quantitative imaging of green fluorescent protein in cultured cells: Comparison of microscopic techniques,use in fusion proteins and detection limits

To determine the application limits of green fluorescent protein (GFP) as a reporter gene or protein tag, we expressed GFP by itself and with fusion protein partners, and used three different imaging methods to identify GFP fluorescence. In conventional epifluorescence photomicroscopy, GFP expressed in cells could be distinguished as a bright green signal over a yellow-green autofluorescence background. In quantitative fluorescence microscopy, however, the GFP signal is contaminated by cellular autofluorescence. Improved separation of GFP signal from HeLa cell autofluorescence was achieved by the combination of confocal scanning laser microscopy using 488-nm excitation, a rapid cut-on dichroic mirror and a narrow-bandpass emission filter. Two-photon excitation of GFP fluorescence at the equivalent of ? 390 nm provided better absorption than did 488-nm excitation. This resulted in increased signal/background but also generated a different autofluorescence pattern and appeared to increase GFP photobleaching. Fluorescence spectra similar to those of GFP alone were observed when GFP was expressed as a fusion protein either with glutathione-S-transferase (GST) or with glucokinase. Furthermore, purified GST?GFP fusion protein displayed an extinction coefficient and quantum yield consistent with values previously reported for GFP alone. In HeLa cells, the cytoplasmic GFP concentration must be greater than ? 1 μM to allow quantifiable discrimination over autofluorescence. However, lower expression levels may be detectable if GFP is targeted to discrete subcellular compartments, such as the plasma membrane, organelles or nucleus.     

Real-time imaging of two-photon-induced fluorescence with a microlens-array scanner and a regenerative amplifier

A real-time two-photon fluorescence microscope with a microlens-array scanner using a regenerative amplifier is presented. The regenerative amplifier generates pulsed laser lights with extremely high peak power and produces brighter two-photon-induced fluorescence compared with that produced without the amplifier. Experimental results obtained from the observation of some biological samples with the proposed microscope are given.     

Functional micro‐concrete 3D hybrid structures fabricated by two‐photon polymerization

Arbitrary micro-scale three-dimensional (3D) structures fabrication is a dream to achieve many exciting goals that have been pursued for a long time. Among all these applications, the direct 3D printing to fabricate human organs and integrated photonic circuits are extraordinary attractive as they can promote the current technology to a new level. Among all the 3D printing methods available, two-photon polymerization (2PP) is very competitive as it is the unique method to achieve sub-micron resolution to make any desired tiny structures. For the conventional 2PP, the building block is the photoresist. However, the requirement for the building block is different for different purposes. It is very necessary to investigate and improve the photoresist properties according to different requirements. In this paper, we presented one hybrid method to modify the mechanical strength and light trapping efficiency of the photoresist, which transfers the photoresist into the micro-concretes. The micro-concrete structure can achieve ±22% strength modification via a silica nano-particles doping. The structures doped with gold nano-particles show tunable plasmonic absorption. Dye doped hybrid structure shows great potential to fabricate 3D micro-chip laser.     

He—Cd热管的特性研究

本文采用ＴＰＦ法测Ｋｒｆ＾＊准分子激光脉冲宽度为对象，研究了荧光介质氦－镉热管的特性，得出了处长Ｈｅ－Ｃｄ热管寿命的结构与特性参数。     

Stark效应对单模热辐射场作用下原子的压缩效应的影响

本文研究了包括Shark效应时双光子Jaynes-Cummings模型中态矢随时间变化的规律。作为例子,讨论了初始时刻有效二能级原子处于基态而光场为单模热辐射场时原子的压缩效应。