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Proceedings Paper

Plasmonic ring laser cavity with tiny footprint
Author(s): Xudong Liu; Feifei Shi; Zhaoyu Zhang
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Paper Abstract

The authors propose a type of plasmonic ring laser which has the footprint smaller than previous published devices, showing the potential to be a single-mode ultra-compact light source. In this structure, CdS gain medium and Ag substrate are separated by an ultrathin MgF2 layer. The short distance between high-index CdS material and silver makes photonic modes of CdS ring hybridize with surface plasmon plaritons (SPPs) of the Ag-MgF2 interface, which leads to strong light confinement in this thin MgF2 gap region. The surface plasmons of this structure carry high momentum, which leads to strong feedback at the ring boundary by total internal reflection forming whispering gallery like mode. Finite difference time domain (FDTD) method is used to calculate and optimize the plasmonic ring geometry. With a 15 nm thick MgF2 layer, the ring’s outer and inner radius can be shrunk to 290 nm and 170 nm with quality factors of 70 at the resonant wavelength of 514 nm. We fix ring width and reduce MgF2 thickness and ring radius to get better confinement. When MgF2 thickness is 5 nm, the outer and inner radius are set as 310 nm and 190 nm respectively, Q factors can reach 93. Free spectral range (FSR) of the ring is around 45 nm, which shows a good ability to generate single mode signal during a large wavelength range. The circled and confined optical fields can significantly enhance light-matter interactions and getting high Purcell factors.

Paper Details

Date Published: 14 March 2013
PDF: 6 pages
Proc. SPIE 8619, Physics and Simulation of Optoelectronic Devices XXI, 86191W (14 March 2013); doi: 10.1117/12.2004075
Show Author Affiliations
Xudong Liu, Peking Univ. Shenzhen Graduate School (China)
Feifei Shi, Peking Univ. Shenzhen Graduate School (China)
Zhaoyu Zhang, Peking Univ. Shenzhen Graduate School (China)

Published in SPIE Proceedings Vol. 8619:
Physics and Simulation of Optoelectronic Devices XXI
Bernd Witzigmann; Marek Osinski; Fritz Henneberger; Yasuhiko Arakawa, Editor(s)

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