A graphene/Ag structure is engineered as an enhanced platform for surface plasmon resonance sensing due to the high impermeability nature of graphene and the superior surface plasmon resonance performance of Ag. This structure is ultrasensitive to even tiny refractive index change of analytes based on Goos-Hänchen shift measurement compared to the traditional SPR sensor with bare Au film. The graphene/Ag configuration is consisted of five components, including BK7 glass slide, titanium thin film, silver thin film, two-dimensional graphene layers and biomolecular analyte layer. We have optimized the parameters of each layer and theoretically analyzed Goos-Hänchen shift of the plasmonic structure under surface plasmon resonance effect. The optimized graphene/Ag structure is monolayer graphene coated on Ag thin film with the thickness of 42 nm.
Phase modulators in surface plasmon resonance phase-differential imaging (SPR-PI) sensing systems reported so far are
sensitive to temperature fluctuations or mechanical vibrations and thus their applications are limited. In this paper, we
propose a novel prism phase modulator (PPM) to replace a traditional modulator. The PPM consists of a parallel prism, a
rotation stage and a mirror. The PPM shows great stability in our experiment, and helps achieve high detection sensitivity
in our SPR-PI system. Moreover, the cost of our PPM is much lower than that of a traditional modulator and is thus suitable
for commercialization. A polydimethylsiloxane (PDMS) microfluidic chip is fabricated to control the flow velocity and
realize parallel detection in our experiment. Measured result of glycerine solution shows that the resolution of our SPR
biosensor array is about 9.11×10<sup>-7</sup> refractive index unit (RIU). Real time monitoring of interaction between bovine IgG and anti-bovine IgG is also realized. The proposed PPM-based microfluidic SPR-PI biosensor array is promising for future
We report multifunctional optical imaging using dye-coated gold nanorods. Three types of useful information, namely, Raman, fluorescence signals, and absorption contrast, can be obtained from a phantom experiment. These three kinds of information are detected in a nanoparticle-doped-phantom using diffuse optical imaging. Our novel nanoparticle could be used as a multimodality marker for future bioimaging applications.