基于迈克耳逊干涉仪的空间调制型干涉成像光谱仪

试制了一台基于迈克耳逊干涉仪的空间调制型干涉成像光谱仪原理样机。样机将迈克耳逊干涉仪光路中的一面反射镜偏转一个小角度,使经两平面镜反射后的两束光波面之间产生一维连续的光程差,在图像传感器的像面上形成空间调制干涉条纹,构成空间调制型干涉成像光谱仪。一系列原理验证性实验表明:光谱仪原理正确可行,实验结果与理论相符,并且具有高通量,高信噪比,大视场和体积小,重量轻的优点。     

毛细管干涉仪的理论分析

从几何光学出发,推导了毛细管干涉仪的从柱面透镜到接收屏的光线的光程．对光线追迹模拟,结果表明毛细管干涉仪的干涉条纹的形成可用双光束的干涉来解释．从柱面不同位置入射的两条光线可能具有相同的光程,而且从柱面透镜不同位置出发的两条光线可能到达接收屏的同一点,当它们满足相干条件时,就会形成干涉条纹．建立了干涉条纹的计算机模拟程序, 模拟了毛细管中液体折射率、毛细管内径、外径对干涉条纹的影响. 结果表明实验中应使用薄壁毛细管, 由于干涉条纹对柱面透镜到毛细管之间的距离非常敏感, 为提高精度, 建议在实验中用已知折射率的标样来确定这一距离.     

斩波式自适应移相干涉技术

研究对环境振动和空气扰动所造成的两相干光束间常数项光程变化不敏感的自适应移相干涉系统，利用偏振分光技术，采用闭环控制，并将高频振幅调制与锁相技术相结合，建立一斩波式自适应移相干涉系统，可对环境振动引起的干涉条纹的抖动进行实时探测并予以光程补偿，将干涉条纹依次锁定在与任意相位差相对应的位置,该方法不受两相干光束间光程差大小的限制且具有高信噪比，阐述了该方法的原理，描述了所建立的系统，并给出了实验结果。     

扫描白光干涉测量技术的算法比较

干涉条纹零光程差位置的确定是扫描白光干涉测量的关键技术之一。介绍了扫描白光干涉法测量物体轮廓的原理,讨论了确定白光干涉条纹零级条纹位置的几种方法,并对随机生成的表面进行了大量的数字模拟测量和分析比较,得出了各种算法对测量准确度的影响。研究结果对白光干涉的应用研究提供了可靠的理论根据。     

用于干涉光谱仪中的新型Wollaston 棱镜系统

提出了一种用于干涉光谱仪中的新型Wollaston棱镜系统———带反射镜的Wollaston棱镜系统。对其结构及光束在其中的传播特性进行了深入分析,并对两束光的光程差进行了计算机模拟。结果表明光程差与入射点位置的关系具有极好的线性,并且所得光程差的动态范围为同类装置的二倍。研究结果为偏振型空间调制干涉光谱仪的设计和应用提供了理论依据。     

孪生光束干涉法测量光源的空间相干性

定量测定光源空间相干性在部分相干光成像, 非相干全息术及光信息处理领域具有重要的研究价值. 本文基于三角全息干涉光路提出了一种测量光源空间相干性的新方法. 利用三角干涉全息光路系统中分束镜产生的孪生光束进行干涉获得干涉图, 通过调整光源中心位置在写入平面内偏离光轴的量, 改变两孪生光束空间分离量的大小, 采集对应的一系列干涉图, 计算干涉图样的对比度, 从而对光源照明空间的波前上一系列不同距离的点对之间的空间复相干度进行测量. 实验系统光路配置较为简单且不需要使用特殊加工的光学元件. 针对一个准单色的扩展光源设计并进行实验, 结果表明利用文中提出的方法可以准确的测量光源的空间相干性, 实验结果相对于理论计算值的误差仅为3.8%. 关键词： 相干性 全息干涉 干涉仪 光学应用     

两种干涉成像光谱技术方案的比较

对"大孔径静态干涉成像光谱技术"方案与以色列学者提出的"两维景物光谱同时测量方法"进行了分析和比较,讨论了这2种干涉成像光谱技术方案中干涉仪与成像光学系统两方面的差异,通过计算机模拟,给出了"两维景物光谱同时测量方法"的光程差非线性变化。受"两维景物光谱同时测量方法"的启发,提出基于横向剪切干涉仪的时间调制型干涉成像光谱技术方案,研究了匀速转动横向剪切干涉仪时,各不同视场像元处光程差的变化规律。     

基于马赫曾德干涉光路的光压测量装置设计

基于马赫曾德干涉原理,设计搭建了可调制与放大干涉条纹的光压测量装置.由频率和功率可调制脉冲激光产生光压,使真空中两面高反镀铝薄膜产生微小形变(位移),从而使由氦氖激光器发射、经半反半透镜分束的参考光和信号光的光程差改变,即干涉条纹发生改变.用CCD记录干涉条纹位移量,数据处理获得干涉条纹位移量和薄膜形变量的关系,计算出脉冲激光在薄膜处的光压.分别讨论了脉冲激光入射角度、频率等参量对检测结果的影响,并通过双角度入射方法消除了热辐射效应的影响.该检测装置可测得最小光功率为15.0mW所产生的光压大小为13.42μPa,线性工作范围为15.0mW(13.42μPa)至200mW(1179μPa),且工作稳定、灵敏度高,测量结果准确.     

气泡的远场干涉分析及应用

提出了一种分析气泡远场干涉的理论模型。平行激光束照射到透明介质中的气泡上,折射光束与全反射光束在远场发生干涉形成内密外疏圆环状干涉条纹,推求了两平行出射光线的光程差公式和两光线之间的距离公式,分析了圆环状干涉条纹内密外疏的原因,给出了计算干涉条纹存在区域和最高干涉级的方法。通过干涉方法可以测量气泡的直径,能够用于介质深处气泡尺寸的测量。利用远场干涉对玻璃水箱、平板玻璃、玻璃棱镜中的气泡直径进行了测量,其中玻璃棱镜中气泡直径测量结果与用阿贝比长仪测量结果对比,相对差为0.9%。预期了气泡远场干涉在运动气泡尺寸、泡内气体折射率、透明光疏介质中光密介质球尺寸测量等方面的应用。     

傅里叶变换光谱仪用于白光光谱测量的实验设计

傅里叶变换光谱仪通过迈克耳孙干涉仪中双光束干涉强度与光程差变化之间的函数关系获得光源的光谱信息.基于自制的傅里叶变换光谱仪,利用光敏电阻和数据采集系统记录动镜沿镜面法线方向匀速运动过程中白光干涉图像的强度变化,得到了白光的相干长度,同时对干涉光强随光程差的分布函数进行了傅里叶余弦变换,得到了被测白光光源的光谱分布.     

Experimental measurement and analysis of the optical trapping force acting on a yeast cell with a lensed optical fiber probe

Based on an optical trapping system with a single-lensed fiber probe inserted at an angle, the sub-picoNewton trapping force acting on a yeast cell as a function of the displacement is measured experimentally by the static and dynamic methods, respectively, whose measurement processes are presented in detail. The measured maximum trapping efficiency is 0.07 in our experiment, which is an order of magnitude lower than that of the optical tweezers. The characteristics of the trapping force in the various horizontal directions are discussed. Finally, the analysis of the measurement error shows the factors and their magnitude which cause error, and offers a way to reduce the error in future.     

Demonstration of high extinction ratio modal interference in a two-mode fiber and its applications for all-fiber comb filter and high-temperature sensor

We show that high extinction ratio (>20 dB) modal interference in a two-mode dispersion compensating fiber can be utilized to build a compact, easy-to-fabricate tunable all-fiber optical comb filter. Wavelength tunability over the full free spectral range of the comb filter is demonstrated with an electrical power of 115mW using an on-fiber thin film micro-heater deposited directly on the fiber. In another configuration, the comb filter is used as a temperature sensor with dynamic range of >300 °C and sensitivity of <0.1 °C. The temperature sensor is capable of measuring a temperature as high as 500 °C.     

Optical arithmetic unit using bit-WDM

A novel arithmetic unit is proposed consisting of a pipelined optical ripple carry adder that adds two words with bits multiplexed by different wavelengths on a single fiber. The addition result is returned to a fiber bus in the same format as the incoming words. The corresponding operand bit pairs are split off the fiber using wavelength division demultiplexers. Full adders compute the sum for each bit pair and the carry from the next lower significant bit pair. The full adder uses couplers and NOT, NOR and novel XOR logic gates constructed using semiconductor optical amplifiers for gain and wavelength shifting.     

Controllable optical bistability and multistability in a rare-earth-ion-doped optical fiber

We investigated the optical bistability and multistability in an Er³⁺-doped ZrF₄–BaF₂–LaF₃–AlF₃–NaF optical fiber inside an optical ring cavity. It is found that the optical bistability and multistability can be easily controlled via adjusting properly the parameters of the corresponding system. Our scheme may provide some new possibilities for technological applications in optoelectronics and optical-fiber communication.     

A high nonlinearity elliptical fiber for applications in Raman and Brillouin sensors

Raman and Brillouin effects have found special applications in distributed sensing for smart materials and structures. In these sensors, the fiber acts as a distributed sensor, sensing strain and temperature over a range of tens of kilometers and, at the same time, carries this information to the installation that will process them. In order to optimize the fiber to operate under the Brillouin and Raman regimes, a special elliptical fiber with small effective area has been designed, which will allow these sensors to cover longer distances and/or employ lower power lasers.     

Dichroic property of the H2O-groups in α-quartz, LiNbO3 and LiTaO3 in the infrared range

The absorptive peaks of the H₂O-groups were observed in the infrared absorption spectra in the vicinity of 3480 cm⁻¹ in LiNbO₃ and LiTaO₃, and 3580 cm⁻¹ in α-quartz. The absorptions of these lines were found to depend on the vibration direction of the polarized incident light, showing the dichroic property in these crystals. The absorption of the ordinary ray waves is much larger than that for the E-ray waves in the crystals. This observation indicates that the direction of the bond vibrations for the H₂O-groups is perpendicular to the optic axis of crystals. The dichroic property of the H₂O-groups may serve as the tracer to study the local electric field in piezoelectric crystals.     

All optical latches using quantum-dot semiconductor optical amplifier

The design and performance of two optical latches, the Set-Reset (SR) latch and D-Flip-Flop has been studied. These latches are the building blocks of large optical processors. The latches are built using two optical logic operations NAND and NOT. Both NAND and NOT operations are realized by using Mach-Zhender interferometer (MZI) utilizing semiconductor optical amplifier with quantum dot active region (QD-SOA). Nonlinear dynamics including carrier heating and spectral hole-burning in the QD-SOA are taken into account together with the rate equations in order to realize the all-optical logic operations. Results show that this scheme can realize the functions of Set-Reset latch and D-Flip-Flop at high speeds (∼250 Gb/s). The dependence of the output quality (Q factor) on QD-SOA parameters is also discussed.     

Temperature dependence of low loss polymeric AWG

We investigate on the variation of loss and temperature dependence of a polymeric arrayed waveguide grating (AWG) depending on its substrate, by fabricating 16-channel polymeric AWGs with various substrate conditions. Insertion loss for a polymeric AWG on a silicon substrate is measured as low as 3.1 dB. The temperature-dependent wavelength shift for a polymeric AWG detached from the substrate is maintained within 0.1 nm from 20 to 80 °C. But we observe a degradation of insertion loss and a little instability in wavelength characteristics both for the detached polymeric AWG and for a polymeric AWG on a polymer substrate. We investigate on those optical properties of the polymeric AWGs based on measured thermal expansion properties of the polymers.     

Method of state code matrixes in the realization of optical switching using Perfect Shuffle

Based on the Left Perfect Shuffle (LPS) optical communication network constructed by cascade multi-stage LPS interconnection, using Looping algorithm, any arbitrary sequence of the input signals can be realized. However, instead of obtaining the simultaneous state codes of the same level node switches through mathematical analytical expressions directly, only routing tags of each channel can be obtained through mathematical analytical expressions so as to draw out topological chart of the network to obtain the state codes implied in the chart. Thus, the states of the switches cannot be directly programmed and controlled by computer in practical application. In this paper, based on the Looping algorithm, a method of stage code matrixes is presented to resolve this problem. By using the method, the simultaneous state codes of the same level’s four node switches can be directly obtained, which is convenient for the computer to provide controlled signals needed to finish the permutation for each node switch. The method of stage code matrixes provides further theoretical basis for the realization of optical switching by integration of Perfect Shuffle and high-speed optical switches.     

Dispersion-Managed Solitons in Multiple-Core Nonlinear Fiber Arrays

The variational principle is employed to obtain the evolution of the parameters of Gaussian and super-Gaussian chirped solitons that propagates through multiple-core nonlinear optical fiber arrays. This is governed by the dispersion-managed nonlinear Schrodinger's equation with strong dispersion management in the presence of linear coupling between the adjacent cores. The results are valid for any configuration of the cores.