Fabry–Perot cavity chemical sensors by silicon micromachining techniques

Micromachined Fabry–Perot microcavity structures filled with polymeric layers composed of poly(3-dodecylthiophene) have been fabricated and studied for use as chemical sensors. The polymer-filled microcavity devices show reversible sensing behavior in response to the exposure of molecular iodine. Here, the chemical dosing results in a dramatic change in the fraction of transmitted light which passes through the microcavity structure (up to 50% at 633 nm). Importantly, the Fabry–Perot microcavity structure produces a significantly larger change in transmitted light intensity compared to a single membrane structure.