Wearable Breath Sensors with Chip Integrated Mid Infrared Slow Light Enhanced Absorbance Spectroscopy on Conformal Flexible Substrates

Omega Optics and the University of Texas Austin propose wearable breath alcohol monitoring with a wearable chip integrated infrared IR optical sensor on flexible substrate Smart sensing is achieved by integrating the devices on flexible substrates with personal clothing Integrated with Bluetooth on the flexible printed circuit board the system will enable real time continuous remote monitoring as also personalized warning notifiers for at risk drivers and drug abusers The chip integrated absorption sensing of gases comprises a quantum cascade laser QCL and quantum cascade detector QCD wafer bonded to silicon passive waveguides in silicon on sapphire SoS wafer Enhanced optical absorbance by the guided light is achieved by using an experimentally demonstrated mid IR holey slotted photonic crystal waveguide HPCW in SoS previously used for detection of chemical warfare simulant triethylphosphate The principle of enhanced absorption relies on the phenomenon of slow light unique to PCW structures and enhanced optical field intensities in low index narrow slots that combine to increase the effective path length traversed by the guided wave through the sensed gas In contrast to conventional QCLs and QCDs that rely on bulky electronic drive circuits and benchtop biasing equipment this proposal transfers experimentally demonstrated printed circuit board based drive elements to a flexible Kapton substrate via demonstrated ink jet printing techniques Distributed feedbacks DFB QCLs on chip emitting multiple discrete wavelengths centered on m and m will monitor both ethanol and carbon dioxide CO in breath respectively Each QCD corresponding to a QCL measures light intensity after transduction by the intermediate HPCW The integrated signal from QCDs generates the absorption spectrum Change in absorption spectrum identifies the gas qualitatively and quantitatively notifying wirelessly via Bluetooth to cell phones or remote devices Our wearable platform can easily detect ethanol with absorption cross section cm molecule with specificity via absorbance signatures down to parts per billion detection limits lower than the ppb in breath corresponding to blood alcohol concentration BAC level The proposed sensing platform together with its potential integration with smart clothing and smart jewelry and accessories will enable applications beyond breath alcohol monitoring to the monitoring of cancers and infectious diseases in civilian and industrial air quality monitoring on airborne platforms and in military law enforcement and fire fighting applications Our system is readily scalable to other wavelengths that will enable monitoring of other gases and vapors This proposal seeks to build a smart wearable chip integrated infrared optical sensor on flexible substrate for the monitoring of breath alcohol at parts per billion that translates to blood alcohol levels less than Integrated bluetooth enables real time continuous remote monitoring as well as personalized warning notifiers for potential at risk drivers and drug abusers The generalized nature of the proposed versatile platform will enable applications beyond breath alcohol monitoring to the monitoring of cancers and infectious diseases as well as in industrial air quality monitoring on airborne platforms and in military law enforcement and fire fighting applications