【摘 要】
：
Active control of the optical parameters in strontium titanate(SrTiO3,STO)thin films is highly desirable for tunable terahertz(THz)integrated devices such as filters,phase modulators,and electro-optical devices.In this work,optically tuned dielectric para
【机 构】
：
School of Science,Minzu University of China,Beijing 100081,China;Optoelectronics Research Center,Min
论文部分内容阅读
Active control of the optical parameters in strontium titanate(SrTiO3,STO)thin films is highly desirable for tunable terahertz(THz)integrated devices such as filters,phase modulators,and electro-optical devices.In this work,optically tuned dielectric parameters of a STO thin film epitaxially grown on a silicon wafer were characterized in the THz region with an 800 nm laser pump-THz detection system.The refractive index,extinction coefficient,and complex dielectric constant of the STO thin film were calculated using thin-film parameter extraction.Owing to carrier transportation and soft-mode oscillation,the above optical parameters changed notably with the pump power of the external laser.This study is of great significance for rapid and non-contact THz phase-modulation technology and may serve as a powerful tool to tune the dielectric properties of the STO thin films.
其他文献
Based on the transport theory and the polarization relaxation model,the effects of hydrogen and hydroxyl passivation on the conductivity and dielectric properties of silicon carbide nanowires(SiCNWs)with different sizes are numerically simulated.The resul
Recently rare-earth chalcogenides have been revealed as a family of quantum spin liquid(QSL)candidates hosting a large number of members.In this paper we report the crystal growth and magnetic measurements of KErTe2,which is the first member of telluride
在人口老龄化背景下,老年人的健康问题日益凸显,老年人对医疗与养老的双重需求越来越显著,其生活质量有待提高.本文综述了国内外学者对医养结合、老年人生活质量等相关概念及理论,对医养结合模式下的老年人生活质量进行研究,旨在探索出一条适合我国国情的医养结合养老新模式,以期提高老年人的健康水平和生活质量.
天然产物一直以来都是药物先导化合物的重要来源.在药物发现领域,基因组数据常用来识别潜在的药物靶点或寻找先前被忽视的天然产物的生物合成基因簇.尽管基因组测序发现了微生物和植物中存在大量未开发的化学多样性,然而,仅仅利用传统的分离分析方法获取新的天然产物已经无法满足药物发展的需求.随着基因组时代的到来,数字化的基因组挖掘已经成为天然产物发现的重要组成部分.伴随着高通量测序方法的发展和DNA数据的丰富,各种基因组挖掘方法和工具被开发出来,以指导发现和表征这些天然产物.本文综述了近年来基因组挖掘的网络工具、数据库
By using quantum Monte Carlo based stochastic analytic continuation(QMC-SAC)and spin wave theory,we study magnetic excitations of Heisenberg models with diagonally coupled checkerboard structures.We consider three kinds of checkerboard models(DC 2×2,DC 3×
This report presents two non-perihperally octaalkyl-substituted nickel phthalocyanines(NiPcs),namely,NiEt2Pc and NiPr2Pc,for use as dopant-free hole transport materials in perovskite solar cells(PSCs).The length extension of the alkyl chains from ethyl to
炔基是许多药物、活性天然产物以及功能材料等的重要官能团,因此,开发高效的炔类化合物合成策略具有重要意义.传统的合成策略包括通过化学反应直接制备,或以简单的炔类前体为底物,通过生物转化获得.随着合成生物学技术的飞速发展,从头生物合成有望成为炔类化合物合成的新策略.该策略绿色环保,易于操作,是对传统化学合成以及生物转化策略的有效补充.炔类化合物从头生物合成的关键是阐明天然产物中炔基的生物合成机制,获得炔基合成酶.本文重点总结了不同天然产物中炔基的生物合成研究进展,包括脂肪酸、聚酮、聚酮-非核糖体肽杂合体、氨基
Superconductivity with transition temperature Tc above 40 K was observed in protonated FeSe(Hy-FeSe)previously with the ionic liquid EMIM-BF4 used in the electrochemical process.However,the real superconducting phase is not clear until now.And detailed st
肉座菌目虫生真菌合成的非核糖体多肽类天然产物具有抗菌、杀虫、抗癌、调节免疫等生物活性,在临床和农业等领域有重要应用价值.近年来,随着真菌基因组测序数量的迅速增加、注释和分析工具的不断进步,人们发现真菌基因组中存在大量产物未知的天然产物合成基因.准确有效地预测这些基因的功能,筛选最有潜力合成新颖天然产物的基因簇,可以提高天然产物挖掘的效率.本研究选取40株肉座菌目虫生真菌基因组,系统分析了编码非核糖体多肽合成酶的基因及基因簇.基于隐马尔可夫模型,预测了445个模块型非核糖体多肽合成酶和1243个类非核糖体多
近年来,一类含有分子内三残基环番结构的新型核糖体肽引起了广泛关注.这类化合物通常由一类S-腺苷甲硫氨酸自由基酶催化核心肽中芳香氨基酸的sp2碳和相邻第三位氨基酸残基侧链的sp3碳之间形成C—C或C—O键,这类酶被称为三残基环番合成酶(3-CyFEs).目前发现Xye类核糖体肽天然产物生物合成基因簇中普遍含有此类三残基环番合成酶.本文报道从Photorhabdus australis DSM 17609中发现一个新的Xye类核糖体肽生物合成基因簇pac.异源表达和体外活性重建表明其生物合成基因簇编码的三残基