Plasmonic linewidth narrowing by encapsulation in a dispersive absorbing material

It is often assumed that adding losses to a resonant system necessarily broadens the width of resonance. Here, scattering spectrum gold nanoparticles in P3HT (strongly absorbing) and PMMA (low loss) were measured using dark field microscopy surprisingly, linewidth was halved lossy medium. To gain physical insight into this unusual result, Green function analysis employed, roles permittivity, both magnitude dispersion, reducing when material are increased made clear. This surprising route narrower linewidths intriguing for nanoplasmonic applications including sensing, spectroscopy, imaging nanolasing also more generally systems where loss conventionally avoided.4 MoreReceived 17 April 2020Revised 30 June 2020Accepted December 2020DOI:https://doi.org/10.1103/PhysRevResearch.3.013014Published by American Physical Society under terms Creative Commons Attribution 4.0 International license. Further distribution work must maintain attribution author(s) published article's title, journal citation, DOI.Published SocietyPhysics Subject Headings (PhySH)Research AreasPlasmonicsSurface plasmon polaritonSurface plasmonsPhysical SystemsNanoparticlesTechniquesDark-field microscopyGreen's methodsCondensed Matter & Materials Physics