象点附近的三维光分布状态的研究

本文根据惠更斯———菲涅耳积分计算 ,引入Lommel函数 ,对象点附近的三维光分布状态进行研究分析 ,计算出象点公差的近似值 。

会聚高斯光束焦点附近的三维光分布状态

根据惠更斯 菲涅耳原理 ,推导出了会聚高斯光束经圆形孔径衍射后焦点附近的三维光分布状态级数表达式 ,并与经典的均匀光波理论进行了比较。讨论了会聚高斯光束焦移与光学系统及高斯光束参数的关系。给出了会聚高斯光束焦点附近的等照度线图。结果表明 ,对于大菲涅耳数系统来说 。

一种绘制二维及三维光能量分布图的简便方法

本文提出了一种在VisualC ++编写的光学测量分析软件中绘制二维及三维光能量分布图的简便方法 ,即由VC调用MATLAB编译器生成的独立的C/C ++SharedLibrary(DLL)。这种方法简单、方便 ,可以完全脱离MATLAB运行环境 ,而且还可以根据需要传递参数绘出可视性极强的二维或三维能量分布图。

圆孔夫琅禾费衍射图样的三维特性分析

基于菲涅耳-基尔霍夫衍射积分公式,在远场傍轴条件下,推导了圆孔夫琅禾费衍射场三维分布的积分表达式,并使用可视化科学计算软件Matlab进行了数值积分,得到了圆孔夫琅禾费衍射图样的三维光强分布数据。展示了焦平面、离焦平面和轴向切面上的二维光强分布图,分析了衍射图样的横向、轴向和离焦光强分布特性,拓展了对圆孔夫琅禾费衍射图样的理解。使用数值计算求解光电场三维分布的方法,无需复杂的特殊函数,利于在大学物理教学中推广。

Research on Testing System for Three-dimensional Distribution of Luminous Intensity of LED

In terms of asymmetrical three-dimensional distribution(ID) of luminous intensity(LI) of light-emitting-diode(LED),a testing system was conducted in this study. Design and principle of the testing system were introduced. 31 photometers were placed on a concentric circle,and all of them were used to gather LI data of LED at the same time. The data acquisition card(DAC) was used to gather multichannel data and controlled motor. Experimental results indicated that the testing system had achieved the goal of testing three-dimensional distribution of LI. And each parameter could meet the requirements of industrial production and measurement.

Simulation of Liquid Argon Flow along a Nanochannel： Effect of Applied Force

Liquid argon flow along a nanochannel is studied using molecular dynamics (MD) simulation in this work.Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) is used as the MD simulator.The effects of reduced forces at 0.5,1.0 and 2.0 on argon flow on system energy in the form of system potential energy,pressure and velocity profile are described.Output in the form of three-dimensional visualization of the system at steady-state condition using Visual Molecular Dynamics (VMD) is provided to describe the dynamics of the argon atoms.The equilibrium state is reached after 16000 time steps.The effects on system energy,pressure and velocity profile due to reduced force of 2.0 (F2) are clearly distinguishable from the other two lower forces where sufficiently high net force along the direction of the nanochannel for F2 renders the attractive and repulsive forces between the argon atoms virtually non-existent.A reduced force of 0.5 (F0.5) provides liquid argon flow that approaches Poiseuille (laminar) flow as clearly shown by the n-shaped average velocity profile.The extension of the present MD model to a more practical application affords scientists and engineers a good option for simulation of other nanofluidic dynamics processes.

Three-Dimensional Sub-100 nm Super-Resolution Imaging of Biological Samples Using a Phase Ramp in the Objective Pupil

Localisation microscopy overcomes the diffraction limit by measuring the position of individual molecules to obtain optical images with a lateral resolution better than 30 nm. Single molecule localisation microscopy was originally demonstrated only in two dimensions but has recently been extended to three dimensions. Here we develop a new approach to three-dimensional （3D） localisation microscopy by engineering of the point-spread function （PSF） of a fluorescence microscope. By introducing a linear phase gradient between the two halves of the objective pupil plane the PSF is split into two lateral lobes whose relative position depends on defocus. Calculations suggested that the phase gradient resulting from the very small tolerances in parallelism of conventional slides made from float glass would be sufficient to generate a two-lobed PSF. We demonstrate that insertion of a suitably chosen microscope slide that occupies half the objective aperture combined with a novel fast fitting algorithm for 3D localisation estimation allows nanoscopic imaging with detail resolution well below 100 nm in all three dimensions （standard deviations of 20, 16, and 42 nm in x, y, and z directions, respectively）. The utility of the approach is shown by imaging the complex 3D distribution of microtubules in cardiac muscle cells that were stained with conventional near infrared fluorochromes. The straightforward optical setup, minimal hardware requirements and large axial localisation range make this approach suitable for many nanoscopic imaging applications.

Light absorption distribution of prostate tissue irradiated by diffusing light source

Determination of light absorption distribution in the prostate tissue irradiated by diffusing light source is important for the treatment planning.In this paper,a three-dimensional(3D)optical model of human prostate is developed,and the light absorption distribution in the prostate tissue is estimated by Monte Carlo simulation method.Light distribution patterns including 3D distributions in the tissue model irradiated by two diffusing light sources are obtained and compared.Also,the impacts of length and energy of cylinder diffusing light source on the irradiance volume are demonstrated.Those results will be significant for the nondestructive qualitative assessments of photodosimetry in biomedical phototherapy.

Assessment of the influence of global dimming on the photosynthetic production of rice based on three-dimensional modeling

Observations indicate that global radiation reaching the Earth's surface has gradually decreased over the past several decades(i.e.,the "global dimming" phenomenon),while the fraction of diffuse radiation in global radiation has increased.It has been found that the increase in diffuse fraction significantly increases photosynthetic production in the canopy,but the mechanism has not been clarified.A three-dimensional light distribution model considering the geometry of incident radiation was employed in this study.This model was used to simulate the light distribution and potential photosynthetic production of rice canopy.The results indicate that the potential photosynthetic production of rice significantly increases in response to an increase in the diffuse fraction as long as global radiation does not decline greatly.The "fertilization effect" of diffuse radiation results from the reduction of leaf area with photosynthetic photon flux density(PPFD) below the light compensation point in response to an increasing diffuse fraction,and an increase in the leaf area with PPFD on the linear part of the light response curve.The increase in the diffuse fraction results in a significant increase in the photosynthetic rate of the upper canopy.High-performance computation is an easy-to-use and economic approach to overcome the computational constraints of the model.