SOI全内反射型光波导电光开关模型研究

根据受抑全反射的光学隧道效应和Ｇｏｏｓ－Ｈａｎｃｈｅｎ位移分析ＳＯＩ全内反射型光波导开关中导模的传输和反射特性。在讨论等离子体色散效应，ｐ－ｎ结大注入效应的基础上，分析了全内反射光波导开关的电学性质。设计了该器件的结构以数和电学参数。     

扩展多模波导全内反射型Y分叉开关的分析

利用全内反射和波导理论，分析了多模波导反射区全内反射(Total Internal Reflection，TIR)型光开关的物理模型和降低串音和损耗的原因，给出改进Y分叉全内反射型光开关特征的近似计算方法。数值模拟表明，扩展多模波导的Y分叉全内反射开关的串音和损耗可分别下降15．5dB和0．65dB以上。     

一种新型全光开关

提出了一种用指数型变耦合系数定向耦合器同高斯型变耦合系数定向耦合器级联所构成的新型全光开关。理论分析及数值模拟均表明,它同用常系数定向耦合器级联所得的器件相比,具有一个很大的优点,即可以消除开关曲线在过开关区中的振荡,因而具有更好的开关特性;同时,它同用高斯型变耦合系数定向耦合器级联所得的器件相比,具有陡峭的动态开关区(即功率透过率从0逐渐升至1的区域)。综上所述,该级联耦合器更加适合于做全光开关,且在满足一定的开关曲线的要求下,可以通过改变各级联耦合器的参量以改变单元耦合器的数目。     

全光数字光开关和光限幅器

分析了级联单端输入非线性光波导耦合器的输出特性。理论分析表明这类器件具有极好的开关、限幅以及稳定光功率的特性。调整耦合器的耦合长度,可改变开关的阈值功率和限幅器的门限,且随着级联耦合器数目的增加,开关的动态开关区、消光比以及输出功率的起伏下降。数值分析表明,级联耦合器作为全光开关,消光比可小于－９０ｄＢ,动态开关区可小于３×１０－４Ｐｃ;作为光功率稳定器和光学限幅器,其输出光功率起伏可小于１０－７Ｐｃ。     

Resolution of Internal Total ReflectionScanning Near-field Optical Microscopy

In this paper, the probe-sample interaction equation based on Mie's scattering theory is derived, and the resolution of scanning near field optical microscopy is calculated numerically. The results show that the offset of far-field component to near-field component in total field plays an important role in the resolution and the size of samples also has influence on resolution.     

Resolution of Internal Total Reflection Scanning Near-field Optical Microscopy

In this paper, the probe-sample interaction equation based on Mie′s scattering theory is derived, and the resolution of scanning near field optical microscopy is calculated numerically. The results show that the offset of far-field component to near-field component in total field plays an important role in the resolution and the size of samples also has influence on resolution.     

基于二维非线性光子晶体的全光开关特性

为获得一个优化的全光开关结构,在光子晶体90°弯曲波导的基础上,进一步改进光子晶体结构,并在其中加入克尔型非线性介质柱,得到了非线性光子晶体全光开关结构。通过时域有限差分(FDTD)法数值分析表明,该开关结构能够实现的带宽大约为50nm,消光比大于40dB,阈值功率密度约为5.2W/μm。同时,该结构还可以实现基本的逻辑功能。     

自聚焦材料弧形全光开关的研究

应用光束传播法,比较基于自聚焦和自散焦材料的全光波导开关的开关特性,指出基于自聚焦材料的全光开关具有较低开关功率、数值化多次开关特性等优越性,并对波导参数进行了全面的优化设计。     

卟啉全内反射同步荧光法测定蛋白质

应用全内反射与同步荧光相结合的技术,建立了利用蛋白质吸附在液-固界面上的同步荧光信号来测定本体蛋白质溶液浓度的新方法。其原理为meso-四(4-磺酸基苯基)卟啉(TPPS)标记牛血清蛋白(BSA)在石英界面的吸附后信号强度随本体溶液浓度的增加呈线性关系。方法的检出限是94 ng·mL-1。用于实际人血清蛋白样品的测定,结果令人满意。     

全内反射型大模式面积光子晶体光纤设计

利用平面波展开法对全内反射型光子晶体光纤的模场分布进行了理论分析和数值模拟,发现通过改变光纤包层结构能够改变模场分布和色散特性,并且利用其特有的"无截止单模"特性,设计了大模式面积光子晶体光纤     

任意偏振态光束全反射时的侧向和横向位移

光束在电介质界面发生全反射时,实际反射光束会在入射面内相对于几何反射光束产生一侧向位移,在垂直于入射面的方向产生一横向位移。利用改进的能流法研究了任意偏振态光束发生全反射时的侧向和横向位移特性。研究表明,侧向位移的大小与入射光束的两组成部分———TE和TM偏振光的相位差无关,而与两组分的光强比密切相关,且该位移可以表示为TE和TM偏振光束各自的位移按光强的加权平均。横向位移的大小不仅与入射光束两组分的光强比相关,还与组分的相位差密切相关。另外,反射光束不仅在椭圆偏振态入射的情况下会产生横向位移,而且在TE和TM偏振态之外的其他线偏振态入射时,也会产生横向位移。     

Phenomenon of Frustrated Total Internal Reflection in the Near-Field Interference Microwave Sounding

Russian Physics Journal - A new approach is proposed in solving the problems of active near-field microwave probing of materials, objects and media. According to this approach, the probing near...     

全内反射型光子晶体光纤横向负荷及扭曲特性研究

用M-Z干涉仪的精确干涉特性来测量光子晶体光纤(Photonic Crystal Fiber,PCF)横向负荷特性及扭曲特性,并应用等效折射率模型对其做了简单的理论分析.实验结果表明:光纤M-Z干涉仪传感臂(即PCF臂)受到外界应力作用时,在固定输入光波长处,PCF的有效折射率n会随外界应力的变化有规律的变化,在横向负荷实验和扭曲实验中表现为干涉条纹的相位与外界应力的变化呈近似线性变化;在横向负荷实验中干涉条纹幅值随所加负载的变化呈近似三角函数变化.     

用全反射方法测量离体动物组织的折射率

利用全反射原理测量了新鲜离体动物组织在650 nm处的折射率.选择了鸡胸肉、猪肌肉、牛肌肉、羊肉、猪肝脏和猪肾脏六种类型的组织作为研究对象,将其制成2 mm厚的切片进行测量,折射率的测量结果范围在1.384 52~1.418 26.特别是对其中肌肉纤维取向明显的鸡胸肉、猪肌肉、牛肌肉,分别测量了肌肉纤维在平行和垂直棱镜与生物组织界面两种情况下的折射率.结果表明,测量的肌肉纤维垂直界面时的折射率要大于平行时的结果.     

All-Optical Bistabilities in Reflection and Luminescence of Thin ZnSe Films

First reports of absorptive all-optical bistabilities in reflectance and luminescence of a Fabry-Perot cavity consisting of thin (0.70 μm) ZnSe film are presented. We demonstrate that the observation of bistability in the reflected beam does not require necessarily the appearance of bistability in the transmitted beam. Luminescence bistabilities, however, are observed both in the light captured from the incident side of the film and in the light emitted from the transmission side. The bistabilities in reflection and luminescence are explained quite satisfactorily by the principle of increasing absorption due to photo-irradiation and the dependence of the luminescence intensity on a photo-thermally induced temperature change, respectively. All experiments were carried out at room temperature with the 488 nm line of an argon laser.     

A Novel Method for Enhancing Goos-Hänchen Shift in Total Internal Reflection

Due to the tiny shift in order of optical wavelength for Goos-Hǎnchen （GH） shift, it is very difficult to directly measure and apply the GH shift. We develop a new method for enhancing GH shift of both TE and TM polarized waves. The method is based on a total reflection prism made of BK9 glass combined with a precise measurement of the resulting spatial displacement with a one-dimensional charge coupled device （CCD）. Measurements are performed to examine the validity of the method. Experimental and theoretical results indicate the feasibility of the method with an enhancement in optical wavelenghth shift at millimetre scale. The method is advantageous to application the GH shift in the optical domain, and is also meaningful for measuring even smaller changes in the refractive index of a liquid.     

Internal Reflection Spectroscopy

Abstract

This review‐type article deals with small, stable, compact, inexpensive, and low‐resolution interferometers mainly based on continuous or back and forth rotational motion to create the optical path difference. These interferometers are suitable for low‐resolution Fourier Transform Infrared (FTIR) spectroscopy. The paper introduces the most typical interferometers illustrated with figures. For example, interferometers with retroreflectors such as corner cubes are presented. This work aims at developing a tilt compensated optical design where the optical path difference of the interferometer will be achieved with rotational scanning. The most important property of this optical design is large mechanical tolerances to make manufacturing easy and inexpensive. New interferometers based on rotational motion are described. The mechanical angle tolerances of these interferometers can be up to three orders of magnitude larger than the angle tolerances in commonly used corner cubes.     

Internal Reflection Spectroscopy

Abstract

The history of internal reflection spectroscopy (IRS), also known as attenuated total reflection spectroscopy (ATR), began nearly two centuries ago with the observation by Newton [l] of an evanescent field in a lower index of refraction medium in contact with a higher index of refraction medium in which a propagating wave of radiation undergoes total internal reflection (TIR). However, the exploitation of this phenomenon for the production of absorption spectra did not begin until the pioneering development work of Harrick [2, 31 and Fahrenfort [4]. After the disclosure on the technique in the literature in 1960, a flurry of publications exploiting it for a wide variety of applications ensued. By 1967 a large body of literature existed which was sufficient to justify a monograph by Harrick [5] and a review by Wilks and Hirschfeld [6], These publications thoroughly reviewed the history and applications of IRS up until that time. Although the IRS technique appeared to promise a ready solution for a wide range of problems which were difficult or intractable by other techniques, such as transmission IR, its general use was hampered by doubts about its reproducibility and capability to be quantitative, Some of the problems which diminished the use of the IRS technique include sample contact to the internal reflection element (IRE) 7-91, spectrometer requirements [101, and data-handling requirements [111.     

Dynamics of a Boundary Layer in Nonlinear Total Internal Reflection Inside a Laser Resonator

Computer simulation of the processes occurring in a thin layer of absorbing liquid adjoining a transparent dielectric with internal reflection from the interface is carried out for the case where the reflector is incorporated into the resonator of a solid-state laser. It is shown that the process of heating the liquid layer near the wall is essentially nonadiabatic. The sharp increase in the pressure of the liquid in the period of maximal heating leads to a situation where the temperatures of switching on and switching off of the total internal reflection at the interface become substantially different. The difference becomes smaller with decrease in the liquid-layer thickness due to a more efficient heat removal, which displays itself as a change in the character of single-pulse laser generation. Periodic emission of nanosecond pulses in the liquid layer in a quasistationary lasing regime is found, whose characteristic feature is stabilization of the liquid-layer temperature.     

Temporal Behavior of Phase Conjugate Wave in Self-Pumped Phase Conjugator with Internal Total Reflection

Several temporal behaviors of the phase-conjugate output of a self-pumped phase conjugator with internal total reflection in BaTiO₃ crystal have been investigated as a function of the beam entrance position and incident angle on the crystal. Different sets of these conditions cause different behavior of phase conjugate wave which are unstable or pulsed output as well as temporally stable output. Classification of these temporal behaviors in phase conjugate wave by incident condition are shown.