共查询到20条相似文献，搜索用时 93 毫秒
1.
利用液晶热光效应的温度特性,并通过传输矩阵法理论,研究了液晶缺陷一维光子晶体的光传输特性。结果表明,当无液晶缺陷时,在较宽的禁带范围出现一条缺陷模,当在光子晶体中引入液晶缺陷时,禁带边缘通带的透射率大幅下降,同时禁带中增加了一条液晶缺陷模,形成双缺陷模特征,且透射率均为100%;随着液晶材料温度的增大,液晶缺陷模的位置向短波方向移动,而随着液晶层厚度的变化其位置向长波方向移动,但右边空位缺陷模的位置并未受到液晶温度和厚度的影响。液晶材料对光子晶体透射谱的这种调制作用,为设计可调谐光子晶体光学器件提供指导意义。 相似文献
2.
利用传输矩阵方法研究了多个周期性分布的负折射率缺陷的一维光子晶体的透射谱.以32个周期的1/4波堆存在5个负折射率缺陷的光子晶体为例进行了数值计算.结果表明:在带隙中产生多个缺陷模,这些缺陷模的分布依赖于缺陷在晶体中的分布.当缺陷密集时,缺陷耦合较强,缺陷模相距较远;当缺陷稀疏时,缺陷耦合较弱,缺陷模相距较近,分立的缺陷模趋于简并,由此形成一个很窄的通带.与正折射率缺陷情形相比较,负折射率缺陷间的相互作用对缺陷模的影响更大,缺陷模谱线也更宽. 相似文献
3.
包含缺陷的一维光子晶体的多通道滤波与宽带滤波 总被引：3，自引：0，他引：3
刘念华 《江西教育学院学报》2002,23(3):12-14
计算了包含多个缺陷的一维光子晶体的透射谱。在层厚为1／4波长的周期性光子晶体中加入多个半波缺陷后，将在截止带中形成多个缺陷模。在缺陷模频率处存在尖锐的共振透射峰，透射峰频率依赖于缺陷层的位置，当缺陷层之间的距离较近时，缺陷模频率相隔较远，这种结构可用于多通道滤波，当缺陷层之间的距离较远时，缺陷模频率相隔较近，此时多个透射峰交迭形成较宽的通带，这种结构可用于宽带滤波。 相似文献
4.
基于磁流体的折射率磁场调控特性,利用传输矩阵法数值模拟了TiO2和纳米磁流体(水基Fe3O4)作为基元材料的一维光子晶体局域模的磁场调控特性.结果表明:具有(AB)NBB(AB)NA结构排列(N为正整数)的一维磁流体光子晶体的局域模波长会随着外加磁场强度的增大向短波方向移动,且最大调控量与周期数无关,折射率n c一定时,局域模波长随着介质层厚度的增大向长波方向移动;局域模的品质因子随光子晶体的周期数、介质层厚度的增大而增大.当光子晶体周期数一定时,局域模波长的调控量将随着介质层厚度的增大而增大. 相似文献
5.
6.
采用传输矩阵的计算方法,研究了一维光子晶体掺杂结构对光传输特性的影响,利用MATLAB绘制不同结构参数的一维光子晶体第一带隙透射率图谱.通过绘图发现：对称一维光子晶体的周期结构（（BA）m（AB）m）,在带隙内部出现光子局域,在中心波长处产生共振隧穿效应;增加对称周期层数,能够降低隧穿效应的透射率,降低光子局域带宽;提高掺杂层折射率,降低光子局域带宽,局域中心向短波方向移动;增大入射角,光子局域中心向短波方向移动;选择适当的结构参数能够实现在1 550 nm光波附近的窄带滤波器的设计. 相似文献
7.
采用时域有限差分技术,分析非线性光子晶体点缺陷不对称结构的单向透射特性。研究发现：当光波从两个不同方向入射,耦合进入缺陷的电场能量不同,入射波存在单向透射特性,从而透射率在跳跃点处的阈值功率不同;此外,入射波在跳跃点处的最大透射率值与入射方向无关。进一步采用耦合模理论验证所得结果,所得结论与数值模拟结果一致。当光波从这种不对称的点缺陷结构两端入射时,所得透射对比度存在一个上限。 相似文献
8.
在A层为双正和双负介质情况下,用传输矩阵法理论研究缺陷层的光学厚度对对称结构一维光子晶体(AB)mC(BA)m透射谱的影响,结果发现:在无缺陷情况下,不论A层是双正还是双负介质,禁带中心均出现超窄频带单透射峰,具有传统对称结构光子晶体透射谱的特征;当中间插入光学厚度等于四分之一中心波长的双正缺陷C后,两者的单透射峰一分为二,且双负情况下两透射峰之间的距离较大;当缺陷C的光学厚度为二分之一中心波长时,双正情况下禁带中心出现单透射峰,双负情况下则出现三条透射峰;当缺陷C的光学厚度等于中心波长时,双正情况下出现三条透射峰,而双负情况下则出现五条透射峰。对称结构光子晶体的透射谱随缺陷光学厚度变化的规律,可用以设计可调性超窄带滤波器。 相似文献
9.
用传输矩阵法理论,研究周期数对一维光子晶体量子阱透射谱的影响,结果表明:随着阱层或垒层周期数的增大,光子晶体量子阱的透射峰均变窄,且垒层周期数增大时透射峰变窄的速度快;垒层介质高低折射率比值越大,或垒层周期数增大,光子晶体量子阱的透射峰变窄速度越快。这些特性,对提高光子晶体光学滤波器件的品质有指导意义。 相似文献
10.
应用On-shell方法研究带缺陷的正方二维圆柱光子晶体,缺陷的引入使得原来不透电磁波的禁带中,出现了缺陷模,即某一波长的电磁波可以透过,计算结果表明缺陷模的频率与透射率随着缺陷的性质,即缺陷的大小和折射率及缺陷两边的层数而变化。 相似文献
11.
邱崇丙 《唐山师范学院学报》2014,(1):21-23
汉字的六书,《说文》对“转注”一类,语焉不详。后世学者提及转注,也仅限于许慎所举出的例字。《汉字例说》一文,作者从转注的角度综合考虑,对部分现代常用字作了分析,跟传统的解释有所不同。希望能抛砖引玉,互相切磋,以推进学术研究。 相似文献
12.
13.
Rachel Zupek 《海外英语》2007,(11):40-41
我们绝大部分人都同意一件事情——我们喜欢金钱。但是你对金钱的喜欢之情足够到让你创立一份事业么?.财富通常被人忽视,主要在于人们不能真正了 相似文献
14.
《海外英语》2007,(4):36
There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love. 相似文献
15.
YANGShiguo 《重庆大学学报(英文版)》2004,3(1):86-88
The problem on the geometrc inequalities involving an n-dimensional simplex and its inscribed simplex is studied. Aninequality is established, which reveals that the difference between the squared circumradius of the n-dimensional simplex andthe squared distance between its circumcenter and barycenter times the squared circumradius of its inscribed simplex is not lessthan the 2(n-1)th power of n times its squared inradius, and is equal to when the simplex is regular and its inscribed siplex is atangent point one. Deduction from this inequality reaches a generalization of n-dimensional Euler inequality indicating that thecircumradius of the simplex is not less than the n-fold inradius. Another inequality is derived to present the relationship betweenthe circumradius of the n-dimensional simplex and the circumradius and inradius of its pedal simplex. 相似文献
16.
Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject. 相似文献
17.
18.
GUO Bao-feng Xiao Da-wei 《重庆大学学报(英文版)》2005,4(3):129-133
Using virtual reality for interactive design gives a designer an intuitive vision of a design and allows the designer to achieve a viable, optimal solution in a timely manner. The article discusses the process of making the Virtual Reality System of the Humble Administrator＇s Garden. Translating building data to the Virtual Reality Modeling Language （VRML） is by far unsatisfactory. This creates a challenge for computer designers to do optimization to meet requirements. Five different approaches to optimize models have been presented in this paper. The other methods are to optimize VRML and to reduce the file size. This is done by keeping polygon counts to a minimum and by applying such techniques as object culling and level-ofdetail switching. 相似文献
19.
The awareness of individualism can be traced back to the period of American Revolution when the Declaration of Independence was produced.It expressed basic beliefs concerning freedom,equality,democracy,privacy and the relationship between people and government,which were exactly what the philosophy of individualism mostly dealt with at that time.This paper is to exploit the essence of individualism by analyzing the Declaration .The analysis enables us to reconsider its significance to the issue of America human rights and foreign policies. 相似文献
20.
Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities. 相似文献