| This dissertation chronicles initial work towards the development of a new chemical and biological sensor transduction methodology based upon the analyte-induced modulation of diffracted light intensity from chemoresponsive gratings. Micropatterning of a "receptor" material into a periodic array on the length scale of the wavelength of visible light, results in the creation of a visible-region diffraction grating due to a periodic contrast in the index of refraction between the patterned lattice and the surrounding media. If the lattice specifically or non-specifically interacts with a target analyte the refractive index contrast will change, resulting in a measurable modulation in the diffracted light intensity. Using this general approach, applications of this methodology to the detection of volatile organic compounds as well as simple biomolecules are presented. Finally, if appropriate probe diffraction beams are used, resonant with either the lattice material or the target analyte, large signal amplification is observed (>3500 times). Described experimentally and developed theoretically, the resonance enhancement phenomenon not only increases device sensitivity but also engenders significant read-out phase selectivity. |
