Nanoplasmonics with Dispersive and Lossy Media
Date
2022-05-24
Authors
Peck, Ryan
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Abstract
This thesis focuses on the physics of nanoplasmonic systems for dispersive and lossy media. Gold nanoparticles in P3HT (poly(3-hexylthiophene)) and PMMA (poly(methyl methacrylate)) are analyzed both theoretically and experimentally. It is found in both cases that the presence of P3HT narrows the linewidth of the gold plasmon peak. This is a counter-intuitive result, and this narrowing of the linewidth by a lossy material is analyzed in detail. It is found that dispersion in both the real and imaginary parts of the permittivity of the surrounding medium can significantly affect the linewidth. Another plasmonic phenomena was also researched. An atomic energy level model of erbium was constructed and used to solve a rate equation to calculate the far-field emission enhancement from an erbium atom nearby a gold nanorod when the dark mode is excited. Normally a small emission enhancement is expected in the far field since dark modes do not couple strongly to radiation, but in experiments this dark field emission enhancement was seen to be significant. The results of the calculation were compared to this previous experimental result. Although the incident power dependence of the calculated 980 nm emission line agreed with experiments, the 650 nm emission line power dependence and the calculated emission enhancement did not, and so more work needs to be done with this model to explain the experimental results.
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Keywords
nanoplasmonics, loss, absorption, nanophotonics, P3HT, nanoparticles, linewidth, narrow, sensing, optics