Coherent and Polarized Random Laser Emissions from Colloidal CdSe/ZnS Quantum Dots Plasmonically Coupled to Ellipsoidal Ag Nanoparticles

Coherent and Polarized Random Laser Emissions from Colloidal CdSe/ZnS Quantum Dots Plasmonically Coupled to Ellipsoidal Ag Nanoparticles

2016/11 Yung-Chi Yao, Zu-Po Yang, Jung-Min Hwang, Hai-Ching Su, Jing-Yu Haung, Tzu-Neng Lin, Ji-Lin Shen, Min-Hung Lee, Meng-Tsan Tsai, and Ya-Ju Lee

Abstract: 

We demonstrate the capability of controlling the optical anisotropy of lasing emissions by manipulating the coupling strength spatially and spectrally between the oscillated electric field of emitted light and the localized surface plasmon (LSP) resonance for 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 has been found that lasing emissions of the revealed system exhibit 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 oscillated electric field of emitted light from colloidal CdSe/ZnS QDs and the ellipse axis of Ag NPs, plays a critical role in selective excitation of LSP resonances leading to the laser emissions with preferential optical polarizations. That is further examined and validated by the finite-difference time-domain (FDTD) simulation. The achievement of spatial and spectral coupling of LSP resonance with colloidal QDs respectively by the spin coating thin QDs film on Ag NPs and control of the Ag NP geometry make the present system one of the promising candidates of colloidal QDs-based random lasers to achieve coherent and polarized lasing emissions.

•  Link:

http://onlinelibrary.wiley.com/doi/10.1002/adom.201600746/full

• International Journals (國際期刊):

Yung-Chi Yao, Zu-Po Yang, Jung-Min Hwang, Hai-Ching Su, Jing-Yu Haung, Tzu-Neng Lin, Ji-Lin Shen, Min-Hung Lee, Meng-Tsan Tsai, and Ya-Ju Lee, Coherent and Polarized Random Laser Emissions from Colloidal CdSe/ZnS Quantum Dots Plasmonically Coupled to Ellipsoidal Ag Nanoparticles, Advanced Optical Materials · 28 November 2016
(DOI: 10.1002/adom.201600746)

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