Microfabricated interferometer and integrated fluidic channel for infrared spectroscopy of aqueous samples
Additional Document Info
Components of a microspectrometer for operation in the infrared range has been designed, fabricated, and characterized. An adjustable Fabry-Perot interferometer is used to select the resonant frequency of the system through electrostatic actuation, allowing tuning for certain optical frequencies to pass. Silicon microfabrication techniques are employed for the fabrication of the device. The intended use of the device is for spectroscopic study of liquids in biomedical and environmental applications; therefore, a sample containment chamber has been integrated into the device. The device was designed using Finite Element Modeling to determine the stress distribution on the silicon nitride membrane due to deflection and the voltage required for the suitable displacement of the membrane to which one mirror is attached. The devices have been fabricated using a combination of processing steps to sputter gold mirrors on nitride membranes, to deposit electrodes and spacers using evaporation and photosensitive polyimide, to etch channels and sacrificial layers, and to bond chips to obtain a resonant cavity. Optical characterization was performed with an FTIR spectrometer. Initial results presented here support the feasibility of the approach in developing standalone microspectrometers for analysis of aqueous samples including biological fluids. 2002 SPIE 1605-7422/02/$15.00.