Physics Commons^™

Molecular Fluorescence In The Vicinity Of A Charged Metallic Nanoparticle, H. Y. Chung, P. T. Leung, D. P. Tsai

Physics Faculty Publications and Presentations

The modified fluorescence properties of a molecule in the vicinity of a metallic nanoparticle are further studied accounting for the possible existence of extraneous charges on the particle surface. This is achieved via a generalization of the previous theory of Bohren and Hunt for light scattering from a charged sphere, with the results applied to the calculation of the various decay rates and fluorescence yield of the admolecule. Numerical results show that while charge effects will in general blue-shift all the plasmonic resonances of the metal particle, both the quantum yield and the fluorescence yield can be increased at emission …

Multi-Level Surface Enhanced Raman Scattering Using AgoX Thin Film, Ming Lun Tseng, Chia Min Chang, Bo Han Cheng, Pin Chieh Wu, K. S. Chung, M. K. Hsiao, H. W. Huang, D. W. Huang, Hai-Pang Chiang, P.T. Leung, D. P. Tsai

Physics Faculty Publications and Presentations

Ag nanostructures with surface-enhanced Raman scattering (SERS) activities have been fabricated by applying laser-direct writing (LDW) technique on silver oxide (AgOx) thin films. By controlling the laser powers, multi-level Raman imaging of organic molecules adsorbed on the nanostructures has been observed. This phenomenon is further investigated by atomic-force microscopy and electromagnetic calculation. The SERS-active nanostructure is also fabricated on transparent and flexible substrate to demonstrate our promising strategy for the development of novel and low-cost sensing chip.

Visualization Of Optical Wave Propagation In Femtosecond Photoemission Electron Microscopy, Rolf Kӧnenkamp, Robert Campbell Word, Joseph Fitzgerald

Physics Faculty Publications and Presentations

Photoemission electron microscopy (PEEM) combines in a unique way photon probing and electron imaging. The imaging electrons are generated in a photoelectric process by illuminating the sample with ultra-violet or x-ray light. After generation these electrons are accelerated and introduced into an electron-optical system to produce a microscopic image of the specimen surface. The advantages of PEEM are manifold:

The avoidance of electron beam exposure makes PEEM a much gentler method than standard electron microscopy. This advantage is important when fragile organic or biological structures are studied. PEEM is also highly surface sensitive, since the photoelectrons typically escape the sample …