The focus of this project is to research, develop, prototype and commercialize high sensitivity multiplexing rapid blood analyzers which can be deployed at the point-of-care. This project involves four research thrusts that culminate in the development and integration of key technology elements comprising of: NPS elements, state-of-the-art microfluidic devices for blood processing, portable optical imaging systems and spectrometers all packaged in a portable instrument with an intuitive user interface. The four thrusts and the corresponding objectives are summarized below:

· Developing integrated nanophotonic-microfluidic devices

· Developing on-chip whole blood processing devices.

· Prototyping hand-held integrated nanophotonic-microfluidic multiplexing blood analyzers.

· Technology demonstration, preliminary validation and commercialization

A diffraction grating is an optical component that has a periodic structure that splits and diffracts light into various beams that travels in different directions. The direction in which the beam travels depends on the gratings width and the wavelength of light so that the gratings act as dispersive elements. Such gratings can be either transmissive or reflective. We propose a width dependent gradient in the refractive index across the gratings which in turn supports waveguiding characteristic in the direction of increasing index, i.e., toward the central groove. The gratings comprise of metal-insulator-metal (MIM) grooves that act as Fabry- Perot resonators due to strong coupling of surface plasmon polaritons (SPPs) on the side walls of the grooves.

In these structures, optimal energy transfer between the incident light and the excited SPPs is achieved through impedance matching including that of the surface SPPs and the resonant modes of each groove, which together yield high intensity localized fields. Further, appropriately designed graded gratings support multiple resonant modes thus enabling multiwavelength SERS, a significant advantage over previously reported plasmonic gratings of constant or random groove-widths wherein light coupling is only maximized at single wavelengths. (N. Kazemi et al., 2018)