比较水和砂的比热容--模拟二种典型气候的对比演示

比热容概念的教学中，几乎任何教材、任何教师都会列举二种典型气候——海洋性气候和大陆性气候的形成原因：水的比热容比砂石大得多．如果能人为地建造这么二种微型的气候环境，现场模拟演示这二种气候特征及其形成原因，显然会增进学生对比热容概念的理解和学习兴趣，同时增加环保意识．我们对此作了初步探索，抛砖于此。     

宽带光纤耦合器的特性研究

应用局部耦合模理论，对非对称臂宽带光纤耦合器熔锥的形成及耦合发生过程作了较为精确的分析，计算得出了这类耦合器的熔锥特性曲线及光谱特性曲线，本文理论的进一步简化可得到一个特例，它与其它文献所用理论一致     

Chiral Parameter of Transparent Films Containing Polymer Cholesteric Liquid Crystal-R

The transparent film containing a kind of polymer cholesteric liquid crystal-R was fabricated by the freezing method. The optical polarization response of the film was investigated by a self-manufactured apparatus and its optical rotatory dispersion was measured by a novel technique at the wavelength from 35Onto to 66Onto.At various wavelengths, the chiral parameter of the film has been obtained. The results show that the chiral parameter decreases as the wavelength increases. The maximum and minimum chiral parameters are 0.0343 at the wavelength of 350 nm and 0.0058 at the wavelength of 660 nm, respectively. The obtained data indicate that this kind of polymer cholesteric liquid crystal-R is a promising candidate host material for solid optical chiral waveguides.     

PDLC调制法测试研究非线性材料的相关性能

针对粉末倍频测试过程中的信号溢出,根据Kurtz理论和聚合物分散型液晶薄膜(polymer dispersed liquid crystal,简称PDLC)的透光率对所加电场电压的响应原理,提出PDLC调制入射基频光强,进而控制测试信号的溢出。利用这一方法分别对碘酸钾、钒酸铯和钒酸铷等几种粉末样品的非线性倍频效应进行了测试分析。计算分析结果为:碘酸钾能够实现相位匹配,钒酸铯和钒酸铷不能实现相位匹配;钒酸铯、钒酸铷的倍频效应分别约为氘化磷酸二氢钾(DKDP)的8.13倍和1.78倍。结果表明,使用PDLC调制法所得的测试结果准确且操作简便。更重要的是,此方法应用于定量测试倍频系数中,可以有效提高测试精确度,并且可应用于其他晶体非线性特性的测试研究。     

新型内反射旋光光学滤波器研究

基于氯酸钠晶体的各向同性和旋光色散特性,利用线偏振光以Brewster角内反射时P分量反射率为零的特性,研制出一种新型内反射旋光光学滤波器,该光学滤波器仅需采用单个偏振片,即可达到良好的滤波效果.利用Mueller矩阵对该滤波器的滤波特性进行理论分析以及实验测试,结果表明对含有532 nm和632.8 nm谱线的线偏振光,改变起偏器角度即可连续调制出射红、绿光的光强,当起偏器较初始位置旋转过133.36°和173.06°时,绿光和红光分别消光,绿光和红光的隔离度可达10 dB. 关键词： 光学滤波器 各向同性 旋光色散 偏振     

微米手性晶粒凝胶玻璃的制备及其消偏振效应

采用干法粉碎法将具有手性特征的块体水晶粉碎成粒径为70μm的手性晶粒，利用溶胶-凝胶法，将粒径为70μm的手性晶粒均匀地撒入凝胶基质中，制成厚度为4mm的含微米手性晶粒的凝胶玻璃，发现其表现出了消偏振效应.而将微米手性晶粒替换成同样尺寸粒径的玻璃粉体，以同样方法制成的相同厚度的含微米玻璃粉体的凝胶玻璃却表现出线偏振保持的性能.分析了此现象发生的原因. 关键词： 手性晶粒 溶胶-凝胶 消偏振     

利用飞秒激光双光子技术制备微电极的研究

基于飞秒激光双光子聚合微加工技术,利用负光刻胶刻蚀方法制备了内部镂空特殊结构的微电极光刻胶样品,并结合剥离法成功制备了一种镀银的金属微电极,最后利用直通管将微电极进行封装,测试了当直通管填充不同的介质(空气、丙酮、水)时微电极的电容变化值.实验结果表明,所制备微电极样品的电容值与介质的介电常数成正相关,实测值与理论计算值的变化趋势一致.     

Chiral organic glass and its infrared spectrum property

Chiral molecules griseofulvin were disseminated homogeneously in poly methyl metahcrylate (PMMA) host, which agglomerate from methyl metahcrylate and N, N-dimethyl formamide dimethyl acetal, using benzoyl peroxide as a catalyst. So the chiral organic glass has been manufactured successfully. Its optical rotatory were investigated from a solution state to a solid state. The results of measurement show that the chiral parameter of the chiral organic glass is 2.65×10^{-7} and its specific rotation has increased compared with its solution condition. Its infrared spectra property has been measured by Fourier transformation infrared spectrometer. The results show that the chiral molecules fill in the pore of the network structure in the organic glass, which hardly link with the host.     

Optical filter based on internal reflection and optical rotatory dispersion of NaBrO3 crystal

Based on the optical rotatory dispersion and zero reflection of the p-polarization light at the Brewsterangle, a novel optical filter that employs only one NaBrO3 crystal and one polarizer are proposed and demonstrated. Performance of the optical filter is studied both theoretically and experimentally. Results show that the green light is becomes nearly extinct when the angles of the polarizer are set at 80° and 260°, whereas the red light becomes nearly extinct when the angles of the polarizer are set at 116°and296°. Isolation of more than 8 dB can be achieved. The measured extinction ratios are 12.3 and 12.6 dBfor green and red lights, respectively.     

一种改进型菲涅尔棱体的设计与分析

通过对光学材料和器件内全反射角的优化设计，提出一种改进型菲涅尔棱体模型，使入射光在器件内以相同的内反射角θ在两种不同玻璃材料和空气构成的界面上发生两次全反射，由反射引起的相位延迟的变化可以相互补偿，从而设计出对入射角不敏感的相位延迟器.计算表明，入射角变化±2°时，该相位延迟偏差不超过0.36°，且保持了原型菲涅尔棱体正入射和正出射的优点，大大方便了使用. 关键词： 相位 全内反射角 折射率