光在一维光子晶体中的全反射贯穿效应

为了研究一维光子晶体中光波的全反射贯穿效应,利用传输矩阵法计算了TE波和TM波在大于全反射角入射一维光子晶体的透射率.在透射波中发现了全反射贯穿效应,得出了全反射贯穿效应随入射角的变化规律、全反射贯穿效应的波长特性以及全反射贯穿效应随介质光学厚度的变化规律.利用波的量子理论和渐逝波的理论对一维光子晶体的全反射贯穿效应作出了理论解释.     

光在一维光子晶体中的全反射贯穿效应

为了研究一维光子晶体中光波的全反射贯穿效应,利用传输矩阵法计算了TE波和TM波在大于全反射角入射一维光子晶体的透射率.在透射波中发现了全反射贯穿效应,得出了全反射贯穿效应随入射角的变化规律、全反射贯穿效应的波长特性以及全反射贯穿效应随介质光学厚度的变化规律.利用波的量子理论和渐逝波的理论对一维光子晶体的全反射贯穿效应作...     

FTIR装置调Q开关性能参数及其测试的研究

本文分析了受抑全内反射(Frustrated total internal reflection)的理论基础,研究光线透射率、反射率相对于棱镜相对间隙d/λ之间的关系,建立了一套实验装置对其进行验证。     

电介质膜对受抑全内反射结构中古斯-汉欣位移的增强

受抑全反射结构中,反射光束和透射光束的古斯汉欣(Goos-Hanchen)位移同时存在,对称双棱镜结构的受抑全反射古斯汉欣位移通常只有波长量级,在实验中很难测量。计算了在入射角大于棱镜与空气界面的临界角小于棱镜与薄膜界面临界角时,镀有电介质膜的对称双棱镜的受抑全反射过程中入射光束的反射系数和透射系数的复数表达式。利用稳态相位法计算得出透射光束和全反射光束的古斯汉欣位移。结果表明,反射光束和透射光束古斯汉欣位移量相同,与入射角大小、薄膜厚度以及空气层厚度有关。在入射角小于但接近棱镜与薄膜界面的临界角,薄膜厚度和空气层厚度一定时,古斯汉欣位移量共振增强达到波长的数百倍。     

光纤回音壁模式激光产生长度的实验与理论研究

采用沿光纤轴向光抽运消逝场激励增益的方式,获得了沿光纤轴向较长范围的回音壁模式激光辐射.研究了这种激光器的激光产生长度与抽运能量间的关系.实验发现:当抽运能量刚超过激光产生阈值时,激光产生长度迅速增长;随抽运能量的继续增加,产生长度的增长趋势变缓;产生长度随抽运能量的变化关系决定于增益包层溶液的染料浓度和溶液折射率.根据抽运光沿光纤轴向以受抑全反射方式传播的物理特性,在抽运能量中引入了遵循比尔吸收定律的指数衰减函数,结合消逝场激励增益的回音壁模式激光理论,在分析系统增益和损耗的基础上由激光阈值条件推导出了 关键词： 回音壁模式 受抑全反射 消逝场 激光产生长度     

可用于拓宽光波单向传输带宽的光子晶体异质结构界面

基于光波单向传输的全光二极管在集成光通信、全光网络和光信息处理中有重要应用.基于方向带隙失配设计的光子晶体异质结构可实现光波单向传输,但正向透射率较低,带宽较窄.基于对光子晶体异质界面倾斜角度的研究,根据界面全反射条件,利用可集成材料硅和二氧化硅设计了一种空气孔型二维光子晶体异质结构.异质结构界面两侧的光子晶体对1550 nm波长附近的TE模光波在Γ-X方向均呈导带,避免了方向带隙失配.研究发现当异质界面满足全反射条件时,由于光子晶体的自准直效应,较宽波段的正向光波得以高效传播,而反向光波在界面由于全反射而被禁止传播.光子晶体异质结构界面的全反射效应打破了方向带隙对光波单向传输的限制,使得反向光波在光子晶体中为导带时同样可实现近零透射率,从而拓宽了光波单向传输的波长范围.基于全反射界面的光子晶体异质结构经过优化后,其正向透射率达0.64,透射对比度为0.97,单向传输带宽可达553 nm.     

各向异性光子晶体的全反射隧穿偏振特性

为了研究一维各向异性光子晶体的全反射隧穿偏振特性,利用传输矩阵法计算了TE波和TM波以大于全反射角入射一维各向异性光子晶体时的透射率,在透射波中发现了TE波和TM波的一、二级全反射隧穿带.得出了与一维各向同性光子晶体的全反射隧穿效应的不同点,即TE波和TM波的一、二级全反射隧穿带的频率中心和频率宽度存在着较大的差异,利用这个特性可以将两种偏振光进行频率分离,为设计优质偏振滤波器提供理论依据.     

圆柱光子晶体全反射隧穿的梳状滤波特性

研究一维圆柱光子晶体的全反射隧穿的梳状滤波特性,利用传输矩阵法计算光在大于全反射角入射一维圆柱光子晶体的透射率.在透射波中发现全反射隧穿效应,全反射隧穿峰具有优良的梳状滤波特性.得到圆柱光子晶体的全反射隧穿随周期数、模式量子数以及圆柱半径的变化特征,为设计性能优良的梳状光子晶体滤波器提供理论依据.     

基于PASCO系统的物质折射率测量

设计了基于全反射原理和PASCO系统的角度扫描物质折射率计算机测量方案.用波长650 nm的激光,测量了水和酒精的折射率,与公认的测量结果较为吻合.通过在透射方观察找到全反射现象,且因出射光线与入射光线的方向是在同一方位,所以透射方并无需转动.引入PASCO系统可测量得到总透射率随入射光角位置的变化关系曲线.     

偏振光在多层散射介质中传输的蒙特卡罗模拟研究

基于米氏散射理论,运用斯托克斯-穆勒形式,结合子午面法和拒绝法,提出了偏振光在多层散射介质中传输的蒙特卡罗模型,并首次分析了当菲涅耳公式失效时,多层介质界面处的全反射行为.同时用该模型研究了微粒直径和介质折射率对漫反射和漫透射的影响.结果表明:无论是折射率匹配介质还是非匹配介质,当粒子浓度一致时,漫反射率都随微粒直径的增加而增加,随介质折射率的增加而减小,而漫透射率则相反.研究结果为生物组织的偏振光散射研究提供了理论验证模型.     

Characterization and application of cerium fluoride film in infrared antireflection coating

Cerium fluoride (CeF₃) thin films were evaporated to the germanium substrates at different substrate temperature from 100 °C to 250 °C. Structural and optical properties were characterized by X-ray diffraction (XRD), scan electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The morphology of samples deposited at different temperature can be closely related to preferred orientation. The infrared optical constants were obtained by fitting the transmission spectrum using Lorentz oscillator model. A simple example for fabrication of long-wave infrared broadband antireflection coating was also presented.     

射频磁控反应溅射氮氧化硅薄膜的研究

利用SiOxNy薄膜光学常数随化学计量比连续变化的特性,给出了制备折射率连续可调的SiOxNy薄膜的实验条件。用磁控反应溅射法制备了不同氮氧比的SiOxNy薄膜。研究了不同气流比率条件下薄膜光学常数、化学成分及溅射速率等的变化。用UV-VIS光谱仪测试了透射率曲线,利用改进的单纯型法拟合透射率曲线计算得到了折射率和消光系数。测试了红外傅立叶光谱(FTIR)曲线和X光光电子能谱(XPS)分析了薄膜成分的变化。实验表明薄膜特性与N2／O2流量比率密切相关,通过控制总压和改变气体流量比可控制SiOxNy薄膜的折射率n从1．92到1．46连续变化,应用Wemple-DiDomenico模型计算出光子带隙在6．5eV到5eV之间单调变化。     

Direct ultrasonic-assisted synthesis of sphere-like nanocrystals of spinel Co3O4 and Mn3O4

A simple sonochemical method was developed to synthesize uniform sphere-like or cubic Co(3)O(4) and Mn(3)O(4) nanocrystals by using acetate salts and sodium hydroxide or tetramethylammonium hydroxide (TMAH) as precursors. Influence of some parameters such as time of reaction, alkali salts, and power of the ultrasound and the molar ratio of the starting materials on the size, morphology and degree of crystallinity of the products was studied. Powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), FTIR spectroscopy, Thermal gravimetry analysis and differential thermal analysis (TGA/DTA) were used to characterize the nanocrystals.     

色谱—傅里叶变换红外光谱联用技术

色谱和傅里叶红外光谱的联用是现代分析化学中重要的联用技术之一。本文介绍了最常用的气相色谱(GC)、高效液相色谱(HPLC)以及最近发展的超临界流体色谱(SFC)与傅里叶变换红外光谱(FTIR)联用技术的最新进展,并对联用中常用的两种接口方式,即流动池法和色谱流动相消除法的优缺点作了讨论。     

Low-cost set-up for Fourier-transform infrared spectroscopy in diamond anvil cell from 4000 to 400 cm−1

An experimental set-up for Fourier-transform infrared (FTIR) studies at high pressure in the mid-IR region (400–4000 cm^?1) is constructed using a compact TEO-400 FTIR interferometer module and an external microscopic optical bench with cassegrain focusing objectives. Cassegrain-type reflective objectives act as an excellent beam condenser that facilitates the interfacing between FTIR spectrometer and diamond anvil cell. This set-up is capable of recording transmission and reflection infrared spectra at high pressure. Preliminary results are reported both in the reflection (pressure dependence of polar phonons in CuWO₄) and transmission configuration (polarized light absorption of polar phonons across the wurtzite-to-rocksalt transition in ZnO).     

Resonant tunneling in frustrated total internal reflection

Anomalous light transmission and resonant tunneling in frustrated total internal reflection (FTIR) are theoretically predicted to occur at periodically curved interfaces. For a low-contrast index and for grazing incidence, it is shown that FTIR resonant tunneling provides an optical realization of field-induced barrier transparency in quantum tunneling.     

A New FTIR Method for the Analysis of Low Levels of FFA in Refined Edible Oils

Abstract

This paper summarizes the application of stoichiometric analytical approaches to quantitative IR analysis and describes the development of a rapid and sensitive Fourier transform infrared (FTIR) method using such an approach for the determination of low levels (<0.005%) of free fatty acids (FFA) in refined edible oils. The method simply involves mixing the sample with methanol containing 2 g /L sodium carbodiimide (NaHNCN) on a vortex mixer for 30 s to convert the FFA to their salts, centrifuging the sample to separate the methanol phase containing the FFA salts from the oil, recording the FTIR spectrum of the upper methanol layer in a 100‐µm CaF₂ transmission flow cell, and ratioing this spectrum against that of the NaHNCN/methanol solution. The concentration of FFA salts is determined from the resulting differential spectrum by measurement of the v(COO^?) absorbance at 1573 cm^?1 relative to a reference wavelength of 1820 cm^?1. A calibration spanning the range 0–0.1% FFA (expressed as oleic acid) was devised by gravimetric addition of a defined, pure fatty acid to an acid‐free oil. Validation of the method by standard addition of palmitic acid to a variety of oils yielded an overall standard error of <±0.001% FFA. Comparison of triplicate FTIR and IUPAC titrimetric analyses of oils spiked with palmitic acid demonstrated that this FTIR method was more sensitive, accurate, and reproducible than the titration procedure, the latter having a significant positive bias of ～0.02%. Solvent/oil consumption in the FTIR method is 2 mL/10 g versus 150 mL/20 g for the titrimetric procedure. The FTIR method developed is particularly well suited for the determination of the low levels of FFA in refined oils but can readily be adapted with a simple adjustment of the oil/methanol ratio to cover FFA levels of up to 4.0%.     

Frustrated total internal reflection evanescent switching

The mechanism of frustrated total internal reflection was analyzed according to the theory of optical film. The transmission and reflection functions were developed and the curves of transmission and reflection changing from the relative gap width d/λ, incident angle θ₀, and refraction index n were shown in graphs. We proposed a scheme of experimental device to test the theoretical conclusion. A self-made electronic actuator drove the piezoelectric ceramics of FTIR. Experiments showed that the evanescent of transmission is 80% for He–Ne laser and smaller for YAG laser and Er:glass laser.     

交联聚电解质纳米微粒的合成及研究

交联聚电解质纳米微粒的合成及研究马荣久金晓霞孙辉（吉林大学高分子研究所长春１３００２３）ＳｙｎｔｈｅｓｉｓａｎｄＳｔｕｄｉｅｓｏｆＣｒｏｓｓｌｉｎｋｅｄＰｏｌｙｅｌｅｃｔｒｏｌｙｔｅＮａｎｏｐａｒｔｉｃｌｅｓＭａＲｏｎｇｊｉｕ，ＪｉｎＸｉａｏｘｉａ...     

Green luminescence from triphenylphosphine functionalized single-wall carbon nanotubes

In a simple wet chemical process, purified single-wall carbon nanotubes (SWCNTs) are treated with triphenylphosphine (Ph₃P) at room temperature. The functionalized material is characterized by scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), Fourier transform infrared (FTIR) spectroscopy and Raman spectroscopy. HRTEM micrograph clearly reveals that triphenylphosphine nanocrystals of nearly uniform size are attached to the surfaces of SWCNTs. The hybrid structure shows remarkable green luminescence with peak emission at around 500 nm, under UV excitation. The photoluminescence may be attributed to charge transfer from the electron-donating phosphorous atoms to the carbon nanotubes.