Resonant Cavity Enhanced On-Chip Raman Spectrometer Array with Precisely Positioned Metallic Nano-Gaps for Single Molecule Detection

In this program, Omega Optics and the University of Texas at Austin propose to develop an on-chip surface-enhanced Raman scattering (SERS) spectrometer array for single molecule detection. The sensitivity of the SERS spectrometer comes from the 5-nm gap between gold nanowires, which can achieve 108 enhancement factor (EF) for the Raman scattering signals. Especially, these gold nanowires are precisely positioned in the resonant cavity by an exquisite nano-entity manipulation technology --- electrical tweezers, a technique with which one can freely move metallic nanowires to predefined positions. Thus the hot-spots for SERS are obtained by a repeatable and controllable manner. Additionally, the proposed on-chip SERS spectrometer array is based on resonant cavity enhanced (RCE) polymer waveguides with extraordinary optical intensity enhancement. The resonant effect is capable of further increasing the sensitivity of the SERS by at least four orders of magnitude. With 1012 enhancement factor in total, the proposed on-chip SERS spectrometer array is expected to achieve single-molecule-detection capability even for those with very small Raman scattering cross sections. Comparing with conventional free space configuration, the fully packaged on-chip optical waveguide spectrometer array with fiber-optic connectors also offers other desired features, such as ease of use and remote sensing.