基于Skew-Ray追迹法的均匀准直照明TIR透镜设计

依据LED点光源模型发光特性,以特定尺寸圆目标屏获得均匀准直照明为目标,采用Skew-Ray追迹法描述光线和设计TIR透镜,其中将透镜全反射区域进行简化处理,主要通过折射区域的双自由曲面相互配合控制光线实现照明目标。经过对透镜设计结果与1mm×1mm的LED扩展光源模型的组合进行非序列光线追迹模拟,模拟结果表明在距离光源2m范围内特定尺寸目标屏所获得光能利用率至少可达到79.6%,同时目标屏在近场和远场处照明均匀度可分别达到95.9%和83.9%,若以±1°作为光线准直半角标准,目标屏准直光线百分比可分别达到88.6%和73.8%。     

实现近场均匀照明的双自由曲面大角度透镜设计

针对LED单自由曲面透镜近场大角度照明均匀性不足和出光效率低等问题,基于边缘光线理论和网格划分法,设计了内曲面为椭圆型,外曲面为自由曲面的LED双自由曲面大角度透镜.透镜内曲面对LED入射光线进行发散,外曲面对出射光线方向进行控制,实现大角度均匀照明,并减少全反射损失,提高出光效率.采用扩展光源文件对透镜模型进行光学仿真,并利用反馈优化法对外曲面进行优化,提高近场的照度均匀性.研究表明:在相同近场距离条件下,出光角度为143°、151.8°时,单自由曲面透镜照度均匀性为0.55和0.40,出光效率为92.0%和80%,而所设计的双自由曲面透镜照度均匀性为0.84和0.85,出光效率为98.8%和95.0%,照明效果明显改善.     

基于双自由曲面的LED均匀照明准直透镜设计

基于几何光学、能量守恒定律及菲涅耳定律等相关理论,提出了一种双自由曲面半导体发光二极管(LED)准直透镜的光学设计方法,并给出了构建准直透镜模型详细的算法设计。自由曲面是一种关于中心轴旋转对称的曲面,该曲面的二维轮廓在非均匀有理B样条曲线的方法理论基础上,采用ProE软件搭建而成。通过蒙特卡罗光线追迹模拟发现,相比传统的单自由曲面准直透镜,双自由曲面准直透镜不仅提高了照度均匀性,而且在能量利用率上也有显著的提高。研究结果表明,采用双自由曲面将大大提升准直透镜的设计空间,改善LED透镜的光学性能。     

用于LED广告灯箱的自由曲面大角度透镜设计与仿真

基于能量守恒定律和网格划分法,设计了一种实现LED阵列近场均匀照明的自由曲面大角度透镜,其内曲面为椭圆形曲面、外曲面为自由曲面.根据能量守恒定律建立映射关系,对光源和目标面进行网格划分,并结合折射定律,迭代求解出外自由曲面数据点.分析了椭圆形内曲面的长短轴比值对透镜菲涅耳损耗和照度均匀性的影响.结果表明:短轴与长轴的比值在0.35~0.55时,出光效率和照度均匀性最佳.通过反馈优化法对LED阵列进行优化,重新划分网格,使叠加部分光照度减弱,提高了整体光照均匀性.仿真结果表明:仅对透镜外自由曲面的面型数据点进行优化,在目标面高度为80mm,透镜出光角度为157°时,优化后的整体光照均匀度由优化前的0.40提高到0.84,出光效率大于0.9.     

实现LED准直照明的优化设计

为了有效地利用光源能量,满足LED远场照明系统要求,提出了一种实现LED大视场角准直照明的自由曲面透镜设计方法.运用ZEMAX软件序列模式下的多重组态建立透镜结构,在ZEMAX的二次开发环境下,采用宏语言编写自定义优化函数,实现对光学系统的自动优化.通过得到的自由曲面面型数据,借助光学仿真软件进行模拟,模拟光源采用圆面发光的LED朗伯体,视角为180°,透镜材料为PMMA,点光源模拟得到的发散半角在±0.1°以内,能量利用率在87%以上,实现了较高的能量利用率.     

基于LED光源与聚合物光纤束的能量均匀透镜耦合器设计

研究了以大功率发光二极管(LED)作为光源的聚合物光纤束(POFB)透镜耦合器的原理和设计方法,基于能量补偿和坐标迭代法设计了一种能量均匀分布自由曲面透镜耦合器。透镜耦合器由两个折射曲面和两个反射曲面以及一个环形柱透镜面组成,折射曲面将修正的朗伯型大功率LED光束中发散角度较小的光线均匀分配在POFB端面上;反射曲面将LED光束中发散角度较大的光线作为补偿光线进行能量重新分配以提高目标面的照度均匀性,并以光纤束端面的照度均匀性和有效光利用率为优化目标对透镜耦合器结构进行优化设计。光学仿真结果表明,当采用3535规格的LED作为光源时,设计的耦合器可使直径为0.5 mm的20×20根POFB端面照度均匀性达到92%,有效光利用率达到71%。     

基于自由曲面透镜的LED路灯配光优化设计

为了提高光能利用率和照度均匀性,减小炫光的产生,需要对LED路灯进行二次光学配光设计.本文以空间光折射定律为基础,对LED光线空间和路面区域进行一一对应的网格划分,结合优化的双向迭代算法生成自由曲面透镜,实现矩形光斑输出.仿真结果表明,配光后的LED整体光能利用率为90.4%,能量基本被限制30m×13m的矩形区域内,水平方向和垂直方向的照度均匀度分别为83.2%和71.7%.当LED以30m间隔平行排列时,可以在路面形成宽度约为14m的光斑,垂直照度均匀度提高为77.2%.据此开模制造的LED路灯配光曲线为蝙蝠翼型,横向和纵向±62°和±40°范围内的平均照度分别为31.17lx和25.72lx,满足国家道路照明标准,实验验证了该透镜设计算法的可行性和实用性.     

基于定抛物面调制的直下式匀光照明透镜设计

对于近场大角度的匀光照明系统,透镜的一般设计方法是采用内表面为球形的自由曲面透镜设计,计算的自由曲面透镜只需考虑一次折射。但是当角度达到一定范围时,在透镜的内表面容易发生全反射,导致目标面照度不均匀。为了在近场照明系统中得到更大角度的配光,提出一种以合适的抛物面作为自由曲面透镜的内表面的设计方法,内抛物面先对光源的能量进行一次扩散,再计算自由曲面面型,通过模拟仿真,实现了在距离光源15 mm处形成半径40 mm的光斑,均匀度达到95%,能量利用率达到97.8%,相对于传统的直下式透镜,提高了照明的均匀度,同时减少了箱体的厚度。     

实现LED准直照明的优化设计

为了有效地利用光源能量,满足LED远场照明系统要求,提出了一种实现LED大视场角准直照明的自由曲面透镜设计方法.运用ZEMAX软件序列模式下的多重组态建立透镜结构,在ZEMAX的二次开发环境下,采用宏语言编写自定义优化函数,实现对光学系统的自动优化.通过得到的自由曲面面型数据,借助光学仿真软件进行模拟,模拟光源采用圆面...     

实现在不同场合中LED均匀照明的方法研究

 LED自身的发光特点限制了其在照明领域的应用,如何合理分配LED的能量,在目标面上形成理想的照度是一个值得研究的问题。就不同应用场合下如何进行光学设计进行分析,通过采用非成像光学设计中光学扩展度守恒方法得到透镜的方程,分别实现圆形均匀照明和矩形均匀照明,其中圆形照明面照度均匀性达到85%,矩形照明面照度均匀性达到75%,并建立了自由曲面透镜三维模型,结合Tracepro进行光线追迹。仿真结果表明：提出的方法满足相应的照明标准,验证了理论设计的合理性。     

Silicon Photonics Rectangular Universal Interferometer

Universal multiport photonic interferometers that can implement any arbitrary unitary transformation between input and output optical modes are essential to support advanced optical functions. Integrated versions of these components can be implemented by means of either a fixed triangular or a fixed rectangular arrangement of the same components. We propose the implementation of a fixed rectangular universal interferometer using a reconfigurable hexagonal waveguide mesh circuit. A suitable adaptation synthesis algorithm tailored to this mesh configuration is provided and the experimental demonstration of a rectangular multiport interferometer by means of a fabricated silicon photonics chip is reported. The 7‐hexagonal cell chip can implement 2 × 2, 3 × 3 and 4 × 4 arbitrary unitary transformations. The proposed hexagonal waveguide mesh operates in a similar way as a Field Programmable Gate Array (FPGA) in electronics. We believe that this work represents an important step‐forward towards fully programmable and integrable multiport interferometers.     

Focal waveforms with tunable carrier frequency using dispersive aperturing

We introduce the concept of dispersive aperturing involving a beam truncation by hard-edge apertures where diameter of the processed beam changes upon frequency. Applied to focused waves, this procedure transforms power spectra at the focal point (and the surroundings). Waveforms at focus conserve pulse duration but carrier frequency may be altered substantially. In principle, some degrees of freedom allow carrier-frequency tuning at convenience.     

Augmented low index waveguide for confining light in low index media

Guiding light in the low index region of a high refractive index contrast waveguide can be beneficial for many applications including sensing, nonlinear optics and electro‐optics. Existing methods to achieve this goal suffer from fabrication complexity, large loss, or poor optical confinement. We propose a simple structure to achieve a significant enhancement of light confinement in the low index medium. We explain the guiding principle of this structure using geometrical optics, and suggest a number of applications where this guiding structure can provide significant performance benefits. The combination of simplicity, ease of fabrication, and good confinement makes this waveguide an attractive choice for a wide range of applications. To illustrate this, we consider the integration of a nonlinear polymer with a silicon photonic waveguide, and show that significantly better performance with an easier fabrication process can be achieved using this new scheme.

     

Programming matrix optics into Mathematica

The various non-linear transformations incurred by the rays in an optical system can be modelled by matrix products up to any desired order of approximation. Mathematica software has been used to find the appropriate matrix coefficients for the straight path transformation and for the transformations induced by conical surfaces, both direction change and position offset. The same software package was programmed to model optical systems in seventh order. A Petzval lens was used to exemplify the modelling power of the program.     

Quantum coherent versus classical coherent light

The paper shows that the Wigner distribution function of quantum optical coherent states, or of a superposition of such states, can be produced and measured with a classical optical set-up using classical coherent light fields. This measurement cannot be done directly in quantum optics since the quantum phase space variables correspond to non-commuting operators. As an example, the Wigner distribution function of Schrödinger cat states of light has been measured. It is also shown that the possibility of measuring the Wigner distribution function of quantum coherent states with classical coherent fields is unique in the sense that it cannot be extended to other quantum states, not even to the incoherent limit of the superposition of coherent states.     

Spontaneous parametric down-conversion

Spontaneous Parametric Down-Conversion (SPDC), also known as parametric fluorescence, parametric noise, parametric scattering and all various combinations of the abbreviation SPDC, is a non-linear optical process where a photon spontaneously splits into two other photons of lower energies. One would think that this article is about particle physics and yet it is not, as this process can occur fairly easily on a day to day basis in an optics laboratory. Nowadays, SPDC is at the heart of many quantum optics experiments for applications in quantum cryptography, quantum simulation, quantum metrology but also for testing fundamentals laws of physics in quantum mechanics. In this article, we will focus on the physics of this process and highlight a few important properties of SPDC. There will be two parts: a first theoretical one showing the particular quantum nature of SPDC, and the second part, more experimental and in particular focusing on applications of parametric down-conversion. This is clearly a non-exhaustive article about parametric down-conversion as there is a tremendous literature on the subject, but it gives the necessary first elements needed for a novice student or researcher to work on SPDC sources of light.     

低温光学系统的研制

低温光学系统对于在空间探测微弱红外目标有重要的意义。无热效应的光学系统设计保证光学系统的像质不受温度变化的影响。有限元分析方法的结构优化设计,在确保光学性能的前提下使系统的重量达到最轻。特殊的制造工艺充分消除零件内部应力。低温检测的结果表明,光学系统的温度从室温降到100K的低温,在温度变化185K的条件下,系统波面误差几乎没有变化,光学系统都能达到衍射极限的成像质量。     

Cloak an illusion

An illusion counter-part displays the same scattering far-field pattern as that of a real object. In this paper, for the first time, we demonstrate that such an unreal illusion can be cloaked by an external cloak. This phenomenon shall be called ??cloak an illusion??. Numerical simulations were performed to demonstrate such a phenomenon.     

Quantum noise limits to terabaud communications

From a general model of fiber optics, we investigate the physical limits of soliton-based terabaud communication systems. In particular we consider Raman and initial quantum noise effects which are often neglected in fiber communications. Simulations of the position diffusion in dark and bright solitons show that these effects become increasingly important at short pulse durations, even over kilometer-scale distances. We also obtain an approximate analytic theory in agreement with numerical simulations, which shows that the Raman effects exceed the Gordon-Haus jitter for sub-picosecond pulses.     

非线性对称平板光波导TE模色散特性的近似计算

本文利用微扰法,导出了克尔型非线性对称平板光波导TE模传播常数的近似计算公式。结果表明,本文公式得到的结果与精确结果吻合得很好。