Browsing by Author "Zandieh, Omid"

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    Multi-modal, Ultrasensitive Detection of Trace Explosives Using MEMS Devices
    (2016-01-15) Zandieh, Omid; Kim, Seonghwan (Sam); Mohamad, Abdulmajeed; Murari, Kartikeya; Park, Simon
    Multi-modal chemical sensors based on microelectromechanical systems (MEMS) have been developed with an electrical readout. Opto-calorimetric infrared (IR) spectroscopy, capable of obtaining molecular signatures of extremely small quantities of adsorbed explosive molecules, has been realized with a microthermometer/microheater device using a widely tunable quantum cascade laser. A microthermometer/microheater device responds to the heat generated by non-radiative decay process when the adsorbed explosive molecules are resonantly excited with IR light. Monitoring the variation in microthermometer signal as a function of illuminating IR wavelengths corresponds to the conventional IR absorption spectrum of the adsorbed molecules. In addition, micro differential thermal analysis, which can be used to differentiate the exothermic or endothermic reaction of heated molecules, has been performed with the same device to provide additional orthogonal signal for trace explosive detection and sensor surface regeneration. We have demonstrated the successful detection, differentiation, and quantification of trace amounts of explosive molecules and their mixtures.