Project Summary: There is a pressing need to develop improved optical sensors for detecting hazardous chemical and biological substances. We address this need by developing a scheme for matched spectroscopy based on nano-optics. Matched spectroscopy can be interpreted by implementing matched finite impulse response (FIR) filters for fingerprint emission or absorption spectra, that is, we detect a characteristic spectrum by cross-correlating the signal with the target spectrum by means of a custom-designed dispersive element.

We develop a novel implementation of matched spectroscopy based on nanoscopic metal-dielectric grating structures for constructing wavelength sensitive devices. The metal structure forms cavities for optical waves guided by surface plasmons, which yields a distinct spectral response of the structure and allows the identification of a specific spectrum as a simple threshold operation. If successful, this project could result in compact hand-held spectrometers for fast detection of specific materials. Integrating the dispersive structures into conventional spectroscopic instruments would also allow the development of high-end devices that specifically address the needs of security applications.

Project Lead:

Markus Testorf