Nicholas I. Cade

Strong coupling of localized plasmons and molecular excitons in nanostructured silver films

We report on the resonant coupling between localized surface plasmon resonances (LSPRs) in nanostructured Ag films, and an adsorbed monolayer of Rhodamine 6G dye. Hybridization of the plasmons and molecular excitons creates new coupled polaritonic modes, which have been tuned by varying the LSPR wavelength. The resulting polariton dispersion curve shows an anticrossing behavior which is very well fit by a simple coupled-oscillator Hamiltonian, giving a giant Rabi-splitting energy of ~400 meV. The strength of this coupling is shown to be proportional to the square root of the molecular density. The Raman spectra of R6G on these films show an enhancement of many orders of magnitude due to surface enhanced scattering mechanisms; we find a maximum signal when a polariton mode lies in the middle of the Stokes shifted emission band.

Etching gold tips suitable for tip-enhanced near-field optical microscopy

We describe a simple method of fabricating gold tips for tip-enhanced near-field optical microscopy using a single step direct current electrochemical etch. Smooth gold tips with a radius of curvature approximately 40 nm and with an aspect ratio suitable for shear force measurement have been produced in a few minutes. A detailed analysis of the etching process has enabled production of reproducible high quality tips. Near field images of single quantum dots using tips etched with this technique are shown.

Optical characteristics of single InAs∕InGaAsP∕InP(100) quantum dots emitting at 1.55μm

The authors have studied the emission properties of individual InAs quantum dots (QDs) grown in an InGaAsP matrix on InP(100) by metal-organic vapor-phase epitaxy. Low-temperature microphotoluminescence spectroscopy shows emission from single QDs around 1550nm with a characteristic exciton-biexciton behavior and a biexciton antibinding energy of more than 2meV relative to the exciton. Temperature-dependent measurements reveal negligible optical phonon induced broadening of the exciton line below 50K, and emission from the exciton state clearly persists above 70K. These results are encouraging for the development of a controllable photon source for fiber-based quantum information and cryptography systems.

Fine structure and magneto-optics of exciton, trion, and charged biexciton states in single InAs quantum dots emitting at 1.3 μ m

We present a detailed investigation into the optical characteristics of individual InAs quantum dots (QDs) grown by metalorganic chemical vapor deposition, with low temperature emission in the telecoms window around

Spatial imaging of modifications to fluorescence lifetime and intensity by individual Ag nanoparticles

1300\phantom{\rule{0.3em}{0ex}}\mathrm{nm}

A Cellular Screening Assay Using Analysis of Metal-Modified Fluorescence Lifetime

. Using microphotoluminescence (PL) spectroscopy we have identified neutral, positively charged, and negatively charged exciton and biexciton states. Temperature-dependent measurements reveal dot-charging effects due to differences in carrier diffusivity. We observe a pronounced linearly polarized splitting of the neutral exciton and biexciton lines

Use of Raman Spectroscopy in Characterizing Formalin‐Fixed, Paraffin‐Embedded Breast Tumor Samples (abstract)

(\ensuremath{\sim}250\phantom{\rule{0.3em}{0ex}}\ensuremath{\mu}\mathrm{eV})

Chapter 7.2:Fluorescence Lifetime Imaging applied to Microviscosity Mapping and Fluorescence Modification Studies in Cells

resulting from asymmetry in the QD structure. This asymmetry also causes a mixing of the excited trion states which is manifested in the fine structure and polarization of the charged biexciton emission; from this data we obtain values for the ratio between the anisotropic and isotropic electron-hole exchange energies of

1.55-μm range InAs/InP (100) quantum dot telecom devices

{\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{\ensuremath{\Delta}}}_{1}∕{\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{\ensuremath{\Delta}}}_{0}\ensuremath{\approx}0.2\char21{}0.5

The plasmonic engineering of metal nanoparticles for enhanced fluorescence and Raman scattering

. Magneto-PL spectroscopy has been used to investigate the diamagnetic response and Zeeman splitting of the various exciton complexes. We find a significant variation in