Publications by authors named "Md Golam Rabbani Chowdhury"
We have studied dispersion of surface plasmon polaritons (SPPs) in the Kretschmann geometry (prism/Ag/dye-doped polymer) in weak, intermediate, and ultra-strong exciton-plasmon coupling regimes. The dispersion curves obtained in the reflection experiment were in good agreement with the simple model predictions at small concentrations of dye (Rhodamine 590, Rh590) in the polymer (Poly(methyl methacrylate), PMMA). At the same time, highly unusual multi-segment "staircase-like" dispersion curves were observed at extra-large dye concentrations, also in agreement with the simple theoretical model predicting large, small, and negative group velocities featured by different polariton branches.
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- - The study examines reflection spectra of dye-doped and undoped polymers on Ag and Au substrates, revealing unusual dips in the UV range around 375 nm for various polymers on Ag, likely linked to surface plasmon polariton (SPP) properties at the Ag-polymer interface.
- - The reflection dips in Rh590:PMMA and HITC:PMMA on Au were more pronounced and shifted towards shorter wavelengths compared to those on Ag, indicating a different mechanism at play for the dips on Au.
- - No reflection dips were detected for undoped polymers on Au, suggesting the cause of reflection dips on Au substrates is distinct from those on Ag substrates, as the theoretical predictions for SPP refractive index do not align with the