Plasmonically induced coherent and polarized random laser emissions in colloidal CdSe/ZnS quantum dots with ellipsoidal Ag nanoparticles

• Main Authors: Huang, Jing-Yu, 黃靖羽
• Other Authors: Lee, Ya-Ju
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/49673617496459761702

碩士 === 國立臺灣師範大學 === 光電科技研究所 === 104 === We demonstrate the capability of controlling the optical anisotropy of lasing emissions by manipulating the coupling strength between the oscillating electric field of emitted light and the localized surface plasmon (LSP) resonance in a random lasing medium composed of colloidal CdSe/ZnS quantum dots (QDs) and ellipsoidal silver nanoparticles (Ag NPs). Distinctive from the amplified spontaneous emission (ASE) generally observed on the colloidal CdSe/ZnS QDs, it is found that lasing emissions of the revealed system exhibits clear interference features (coherent optical feedbacks) with low-threshold characteristics, mainly attributed to enhanced light scatterings and optical gains arisen in the peripheral surfaces of ellipsoidal Ag NPs. Importantly, the relative orientation, between the oscillating electric field of emitted light from colloidal CdSe/ZnS QDs and the major axis of ellipsoidal Ag NPs, plays a critical role in selective excitation of LSP resonances to promote laser emissions with specific optical polarizations. That is further examined and verified by the finite-difference time-domain (FDTD) simulation. The unique and manipulating properties, associated with the LSP resonance coupling effect of ellipsoidal Ag NPs, make the present system as promising candidates for achieving coherent and polarized lasing emissions based on the colloidal semiconductor quantum dots.