一种新型激光光刀的研究

介绍了一种适用于自由曲面反求工程的新型激光光刀．该光刀产生的原理是通过将激光束投射在柱面反射镜上，反射形成光条．这种方法除了能将激光束展成光条之外，还能压缩光条宽度，再采取压缩光发散角的措施，可以获得景深大、宽度窄、光强横向呈高斯分布的激光光刀．与传统的方法相比，不仅光刀质量好，容易实现，而且有利于计算机采集系统提取光刀中心位置．此外还介绍了新型光刀在应用中表现出来的优点．     

激光光镊拉曼光谱技术的鼻咽癌研究展望

激光光镊拉曼光谱技术是光镊技术与拉曼光谱技术交叉融合的产物,能够用于生理条件下单细胞拉曼光谱的测量和分析,已成为细胞生物学、医学研究中不可缺少的重要工具.综述回顾了激光光镊拉曼光谱测量系统理论和技术的发展,展望了全息光镊、声镊、光电镊、光泳镊等新型光镊与拉曼光谱系统融合的前景;根据激光光镊拉曼光谱技术的特点,系统梳理、分析了该技术在生物医学领域,尤其是鼻咽癌的诊断和治疗领域的应用前景.     

激光诱导动物细胞基因转移的研究

用调 Ｑ Ｎｂ：ＹＡＧ激光器输出的波长为 ３５５ ｎｍ的三倍频光进行人胃癌细胞基因转移的研究。激光束经显微镜的物镜聚焦，在样品平面上获得激光微束。钙黄素和荧光 ＩｇＧ用来模拟 ＤＮＡ分子。激光微束照射细胞，在细胞膜上打出一个可以自行恢复的小孔，同时，荧光物质通过小孔扩散到被照射的细胞内。在荧光显微镜的蓝光激发下，被照射的细胞发绿光。激光能量每个脉冲大约是 ２００ μＪ．脉冲数 １～４，脉冲宽度小于 １０ｎｓ。     

飞秒光镊技术的研究进展

因在光镊及超短激光脉冲方面开创性的工作,A. Ashkin、G. Mourou和D. Strickland分享了2018年度诺贝尔物理学奖。本文概述了将超短激光脉冲和光镊相结合的飞秒光镊技术的研究进展。简要介绍了飞秒光镊技术的基本原理,重点介绍了飞秒光镊技术中的非线性光学效应和光学捕获动力学行为,最后讨论了飞秒光镊技术中的调控手段,展望了飞秒光镊技术的发展前景。     

光纤光镊在生物系统中的应用

对生物细胞及大分子进行无接触、无损伤、高精度的捕获及操控,是目前集成光子学、生物光子学及临床医学等交叉学科领域的国际研究热点之一。本文总结了目前光纤光镊在生物系统中的重要应用,特别是光纤光镊在单细胞操控、多细胞组装及生物细胞成像与探测领域的研究进展。因其具有制备简单、可操控及体积小等优点,光纤光镊在细胞生长、组织分化、疾病诊断与断层显微术等领域具有潜在的应用价值。     

光镊--光的力学效应的研究及应用

激光的发明使得光的力学效应走向了实际应用,光镊是光的力学效应的典型事例。简述了光镊技术的原理和特点——无损伤操控功能和微小力的传感器,介绍具有代表性的研究成果,并展望了光的力学效应研究和应用的发展。     

光阱pN量级阱力的流体力学法测量系统

根据流体力学的分析 ,研究并计算了适合光镊操作生物粒子的无限大平板流场特性和流场分布 ,设计并研制了一套符合光镊pN(皮牛 )量级力测量的液体微循环系统和样品池 ,其液体微流量分流器和缓冲器解决了蠕动泵脉冲缺点 .实际测量和光阱力测试结果显示该系统满足光阱pN量级力的测量要求 .     

捕获与观测纳米粒子技术的进展

光镊是20世纪末激光技术领域的重大发明．它应用光的力学效应有效地操控微小粒子，用于研究纳微尺度下物质相互作用，探讨微观机制，解读生命规律。     

微粒在会聚高斯光束中的受力分析

以射线光学模型为基础,对会聚高斯激光束中微粒所受轴向力进行了计算.数值计算的结果表明,束腰越小捕获越稳定;相对折射率必须大于1并存在一个最佳相对折射率;激光波长、粒子半径以及激光功率也对捕获力有重要影响.数值计算和分析为搭建光镊仪器选取系统参数提供必要的理论依据.     

激光微束新技术研究

本文概述我室在激光微束新技术方面取得的若干研究进展:1)YAG激光器采用BBO晶体腔外倍频;2)实现了一种新的带空间滤波器的激光聚焦系统;3)研制成一种新型的长工作距、短焦距聚焦物镜;4)设计了高倍率的电视图像监测系统;5)研制成功“激光微束细胞辐照仪系统”,其最小聚焦光斑直径≤0.6μm(在6943(?)时);6)研制成功“激光微束细胞打孔仪系统”,其最小打孔直径≤1μm.     

基于电动现象的细胞光镊阱力测量

提出了一种新的细胞光阱力标定的实验方法，利用细胞电泳原理，设计并研制了一套符合用光镊测力的电动样品池系统，用它替代单光镊操作系统中的普通样品池和高精密压电位移驱动平台，可以用电压调控细胞运动速度，系统相对简单、经济．实验测量结果为：在2～18V／cm电压梯度范围内，酵母细胞的运动速度与电压梯度成正线性关系，即在皮牛量级以下，最大光阱力与光镊光源的功率成线性增加关系．测量结果表明，该方法可实现对细胞光阱力的测量，还可用来测量细胞表面电量．     

Measurements of leucocyte membrane elasticity based on the optical tweezers

A 1-μm in diameter polystyrene bead coated with lectin is trapped by optical tweezers whics is formed by a focused laser beam (740nm).A leucocyte adhered to the bottom of sample cell is chosen to close to the trapped bead.When their stable combination is confirmed,the leucocyte is displaced by moving the sample stage.A“tether”is then formed between the trapped bead and the membrane.The force acting on the tether is measured by a detector equipped on the optical tweezers system.The deformation of the membrane is diverse in different contact conditions.When the contact area is small,the tether is very thin and the force on it is 7.4pN(10^-12N),while the tether is much thicker under a larger contact area and its corresponding force is about 14pN.It is presumed that the latter is related to the deformation of cytoskeleton.     

光镊技术在生命科学研究中的发展与应用

介绍了光镊技术的原理和系统结构,追踪了光镊操作和探测技术从微米到纳米的进展,最后给出了纳米光镊在生物技术领域的应用.     

Massively parallel manipulation of single cells and microparticles using optical images

The ability to manipulate biological cells and micrometre-scale particles plays an important role in many biological and colloidal science applications. However, conventional manipulation techniques--including optical tweezers, electrokinetic forces (electrophoresis, dielectrophoresis, travelling-wave dielectrophoresis), magnetic tweezers, acoustic traps and hydrodynamic flows--cannot achieve high resolution and high throughput at the same time. Optical tweezers offer high resolution for trapping single particles, but have a limited manipulation area owing to tight focusing requirements; on the other hand, electrokinetic forces and other mechanisms provide high throughput, but lack the flexibility or the spatial resolution necessary for controlling individual cells. Here we present an optical image-driven dielectrophoresis technique that permits high-resolution patterning of electric fields on a photoconductive surface for manipulating single particles. It requires 100,000 times less optical intensity than optical tweezers. Using an incoherent light source (a light-emitting diode or a halogen lamp) and a digital micromirror spatial light modulator, we have demonstrated parallel manipulation of 15,000 particle traps on a 1.3 x 1.0 mm2 area. With direct optical imaging control, multiple manipulation functions are combined to achieve complex, multi-step manipulation protocols.     

单光束光镊光阱力分析

在几何光学近似下,利用光线追踪法分析了激光微束对微粒的作用力,数值计算中考虑了激光微束的具体结构对光阱力的影响.分析表明:相对折射率和激光束腰对光阱力有重要影响,激光波长和微粒大小对光阱力也有一定影响.     

光镊拉曼光谱技术检测结肠癌细胞的研究

使用激光光镊拉曼光谱分析系统,测量了结肠癌病人的3种不同细胞的拉曼光谱。实验结果显示结肠癌细胞和正常细胞的拉曼光谱有明显的差异,这种差异可以由1002cm^-1和1300cm^-1处的峰值参数来标示。与正常细胞比,结肠癌细胞在1350cm^-1,1458cm^-1,1576cm^-1,1662cm^-1处的强度增加,表明在结肠癌组织细胞中核酸含量增加。在1300cm^-1,1442cm^-1,1647cm^-1,1739cm^-1处的强度减小,表明在结肠癌组织中脂类的含量减少。     

微粒在飞秒激光光场中的受力特性分析

在分析微粒处于连续高斯光束光场和飞秒脉冲激光光场中轴向光阱力特性的基础上,用数值方法计算了两种情况下微粒所受的轴向力,比较了微粒在两种光场中所受轴向力和热效应的异同,导出了飞秒激光光镊实现对微粒捕获的条件．     

Making light work with optical tweezers.

Microscopic objects, including biological material, can be remotely manipulated with tightly focused beams of infrared laser light. The use of optical traps, or 'optical tweezers', holds great promise for noninvasive micromanipulation and mechanical measurement in cell biology. Optical tweezers are the 'tractor beams' of today's technology.     

磁性纳米颗粒的二维光操纵及团聚效应

我们利用暗场显微镜系统地研究了水剂磁性液体中Fe3O4磁性纳米颗粒在高度聚焦激光作用下的动力学过程.实验研究表明:当激光聚焦在样品池中间时,由于受到沿激光入射方向强散射力和吸收力的作用,磁性纳米颗粒会被排开至光斑的外围;当激光聚焦在样品池上表面时,在光力和样品池上玻片的共同作用下,磁性纳米颗粒会被捕获在样品池的上玻片的下表面并发生团聚效应;此外,我们还研究了不同激光功率作用下形成的磁性纳米团簇对入射白光的透过谱的影响,随着入射激光功率的增加,透过磁性液体的白光的透过率会急剧下降,而且透射谱的中心波长会随着入射激光功率的增加往长波方向移动.     

Tunable nanowire nonlinear optical probe

One crucial challenge for subwavelength optics has been the development of a tunable source of coherent laser radiation for use in the physical, information and biological sciences that is stable at room temperature and physiological conditions. Current advanced near-field imaging techniques using fibre-optic scattering probes have already achieved spatial resolution down to the 20-nm range. Recently reported far-field approaches for optical microscopy, including stimulated emission depletion, structured illumination, and photoactivated localization microscopy, have enabled impressive, theoretically unlimited spatial resolution of fluorescent biomolecular complexes. Previous work with laser tweezers has suggested that optical traps could be used to create novel spatial probes and sensors. Inorganic nanowires have diameters substantially below the wavelength of visible light and have electronic and optical properties that make them ideal for subwavelength laser and imaging technology. Here we report the development of an electrode-free, continuously tunable coherent visible light source compatible with physiological environments, from individual potassium niobate (KNbO3) nanowires. These wires exhibit efficient second harmonic generation, and act as frequency converters, allowing the local synthesis of a wide range of colours via sum and difference frequency generation. We use this tunable nanometric light source to implement a novel form of subwavelength microscopy, in which an infrared laser is used to optically trap and scan a nanowire over a sample, suggesting a wide range of potential applications in physics, chemistry, materials science and biology.