The miniaturization of devices, components, and systems represents a growing trend in nearly all areas of technology. In particular, this trend is having a significant impact in the areas of biofluidics, imaging, and communications. In this effort we focus on a technology common to each of these applications, namely, spectral filtering. The spectrometers currently used in these applications are typically large in comparison to their companion system. To this end the work addressed in this proposal is targeted at developing such a spectrometer, i.e., a spectrometer on a chip. Our spectrometer consists of a diffractive lenslet array fabricated on the micron-scale, a precision pin-hole, and a focal plane array. The idea is based on the fact that light of different wavelengths, when incident on a diffractive lens, comes to focus at different axial locations. Therefore, by placing a pinhole at the appropriate axial location of a particular spectral focus, one can effectively perform spectral filtering using a spatial filter. Thus, by scanning the pinhole and reading off the response electronically a complete spectral response, spatially registered to a detector array, can be obtained. The proposed system will be realized through the design of meso-scopic diffractive lenses using custom electromagnetic design algorithms, they will be fabricated using multi-level electron beam lithography and RIE etching, and the pin-hole array will be fabricated in a silicon MEMS scanner. The system will be integrated with readout circuitry using flip-chip bonding.
