物理学院“博约学术沙龙”系列报告
(总第 105 期)

时  间：   2015年11月19日（星期4）下午15:00
地  点：   中心教学楼610
报告一：博士生报告
时间：15:10-15:40
题  目：分布式布拉格反射镜与光栅的相互耦合
报告人：赵晓博                   指导老师：张用友
摘要：光子晶体（Photonic Crystal）是在1987年由S.John和E.Yablonovitch分别独立提出，是由不同折射率的介质周期性排列而成的人工微结构。按照光子晶体的光子禁带在空间中所存在的维数，可以将其分为一维光子晶体、二维光子晶体和三维光子晶体。而分布式布拉格反射镜就是一种常见的一维光子晶体。分布式布拉格反射镜自从70年代末出现以来，由于其良好的滤波特性和灵敏的温度和应变响应，已经在光纤通信、传感和测量领域取得了广泛应用。而光栅是一种经典的分光元件，发展的相当成熟，已经形成了很多种类，制作方法也相当成熟。本文主要对分布式布拉格反射镜进行理论研究，以及其与光栅的相互耦合作用的理论研究。主要研究方法是通过发展转移矩阵的方法使其应用于带有光栅结构的分布式布拉格反射镜。
通过光栅和分布式布拉格反射镜的光学耦合，使两者的光学特性相结合。这种组合不仅实现了共同调控透射行为，而且通过调节结构参数，可以方便地在一定范围内实现调控梳状透射峰的位置、半高宽，使其可以满足各种滤波的需要。通过软件计算结构无序性对透射行为的影响，数据表明，低于25%的结构混乱程度对梳状透射行为影响不大。

报告二：博士生报告
时间：15:40-16:10
题  目： Molecular and metal nanoparticles composite superstructure ：Research on the relationship between CD activities and structures
报告人：  王路明                          
指导老师：王荣瑶
摘要：we design a assemble method based on supramolecular soft template. A three-dimensional structure of gold nanorods was successfully constructed through a hierarchical, cooperative self-assembly/self-organization process in a multiple-component system comprising of gold nanorods, surfactants, and phospholipids film. In addition, a strong circular dichroism response signal is observed in the visible / near infrared region. In addition，we studied the influences of AuNRs/lipid hybrid superstructure and optical activity from magnetic field. This construction of three-dimensional chiral nanostructure may have values in exploiting novel plasmonic nanostructures with tunable optical activity response in the visible/NIR region, and the study of magnetically manipulate seemingly nonmagnetic (diamagnetic) materials can lead to new opportunities to control and steer soft matter.
 
时  间：   2015年11月19日（星期4）下午3:00
地  点：   中心教学楼610
报告三：博士生报告
时间：16:10-16:40
题  目：Stability enhancement of PbSe quantum dots via post-synthetic ammonium chloride treatment for high-performance infrared photodetector
报告人：付春杰                  
指导老师：杨盛谊
摘要：
 Infrared emission lead-selenide (PbSe) quantum dots (QDs) have gained considerable attention in the last decade due to their potential applications in optoelectronic devices. However, the comprehensive applications of PbSe QDs are not realistic yet for their highly susceptible oxidation in air. In this paper, we demonstrate the stability enhancement of PbSe colloidal quantum dots (CQDs) via a post-synthetic ammonium chloride treatment and its applications in solution-processed high-performance infrared photodetector with a field-effect transistor (FET) configuration by reversely fabricating the PbSe active layer and polymethylmethacrylate (PMMA) dielectric layer. The responsivity and the specific detectivity of the FET-based photodetector Au(Source,Drain)/PbSe(52nm)/PMMA(930nm)/Au(Gate) reached 64.17 mA/W and 5.08×1010 Jones, respectively, under 980 nm laser illumination with an intensity of 0.1 mW/cm2. Therefore, it provides a promising way to make high-sensitivity near-IR/mid-IR photodetector.
 
报告四：博士生报告
时间：16:40-17:10
题  目：Quantum transport through a multi-quantum-dot-pair chain side-coupled with Majorana bound states
报告人：      仲成成            
指导老师： 江兆潭
摘要：We investigate the quantum transport properties through a special kind of quantum dot (QD) system composed of a serially coupled multi-QD-pair (multi-QDP) chain and side-coupled Majorana bound states(MBSs) by using the Green’s functions method. It is found that for the nonzero MBS-QDP coupling a sharp AR-induced zero-bias conductance peak is present (or absent) when the MBS is coupled to the far left (or the other) QDP. Then we find that the QD-lead coupling is able to affect the conductances of Leads L and R in different ways, demonstrating that there exists a competition between the AR and ET processes. Finally we consider the effect of the inter-MBS coupling on the conductances of the multi-QDP chains and it is shown that the inter-MBS coupling will split the zero-bias conductance peak into two sub-peaks. This research should be an important extension in studying the transport properties in the kind of QD systems coupled with the side MBSs, which is helpful for understanding the nature of the MBSs, as well as the MBS-related QD transport properties.

联系方式：物理学院办公室（68913163）