We propose to investigate a novel on-chip CMOS-compatible platform of Silicon photonic structures for the detection small numbers of gold nanoparticles that are used as biological labels. Gold nanoparticles can selectively bind to bio-recognition elements and can be used as biological labels using standard biochemistry techniques. The ability to detect single gold nanoparticles will enable ultra sensitive bio-detection of biological molecules. Single particle detection is fundamentally challenging due to the small cross section of the biological labels. The extinction cross-section of the metal nanoparticles used as labels can be enhanced by orders of magnitude using strong light confining on-chip structures, such as resonant microcavities. The presence of a metal nanoparticle with size as small as 5nm can be detected by measuring the decrease in transmission through the photonic structure. The high degree of integration of the light source, detectors and sensors on a single chip will be achieved using high index contrast waveguides with sub-micron size dimensions. In this project we will develop the components for the proposed biosensing platform required for: (i) Routing optical signals on-chip and (ii) Detecting metal nanoparticles using micron-size on-chip Silicon microcavities. We will demonstrate the integration of the different components forming the platform on a single chip.
Broader Impact The proposed research, in addition to its strong impact in the field of biosensing, will form the basis for investigating novel integrated structures for enhancing the interaction of light and matter in integrated systems. Applications include amplifiers, sensors, lasers, etc. These applications will have strong impact in areas such as telecommunications, chemistry, and medicine. As part of this program we will integrate two REU students that will be actively involved in the research. This project lies at the interface of physics, chemistry, applied physics, optics, photonics, and materials science. Our proposal will give undergraduate students an opportunity to be involved in an interdisciplinary project, which should provide them with a very enriching summer research experience. We will also integrate the topic of photonics for biosensing, in two courses currently taught in Cornell for undergraduate and graduate students. The topic will be introduced both in lectures and in lab experiments.
