Single-photon emitters in van der Waals materials

Solid-state sources of single-photon emitters are highly desired for scalable quantum photonic applications, such as quantum communication, optical quantum information processing, and metrology. In the past year, great strides have been made in the characterization of single defects in wide-bandgap materials, such as silicon carbide and diamond, as well as single molecules, quantum dots, and carbon nanotubes. More recently, single-photon emitters in layered van der Waals materials attracted tremendous attention, because the two-dimensional(2 D)lattice allows for high photon extraction efficiency and easy integration into photonic circuits. In this review, we discuss recent advances in mastering single-photon emitters in 2 D materials, electrical generation pathways,detuning, and resonator coupling towards use as quantum light sources. Finally, we discuss the remaining challenges and the outlooks for layered material-based quantum photonic sources.     

GaN衬底的腐蚀程度对ZnO纳米棒阵列光学性能的调控

研究了在湿法腐蚀Ga N衬底上生长的Zn O纳米棒阵列的微结构和光学性能。相比于未经腐蚀及腐蚀5 min、10 min的Ga N上生长的Zn O纳米棒阵列,在腐蚀8 min的Ga N上生长的Zn O纳米棒阵列最细密,光学性能最好,其相应PL光谱峰强积分比IUV/Ivis最大(70.92)。因为此时Ga N衬底中的位错基本全部在表面露头,Zn O容易附着而形成更多的形核种子,并且衬底的位错在表面的边缘有助于诱导Zn O晶体的外延生长,所以Zn O棒更加细密,晶体质量更高,从而光学性能更好。     

确定斜拉桥索力的有约束优化方法

本文建立了斜拉桥索力调整的非线性规划模型,其中以斜拉桥梁和索塔的拉压及弯曲应变能为目标函数,以结构的位移,弯矩及索力为约束,采用梯度投影法进行求解用以确定成桥合理状态的索力。