title: Tunable laser diode system for noninvasive blood glucose measurements.
abstract: Optical sensing of glucose would allow more frequent monitoring and tighter glucose control for people with diabetes. The key to a successful optical noninvasive measurement of glucose is the collection of an optical spectrum with a very high signal-to-noise ratio in a spectral region with significant glucose absorption. Unfortunately, the optical throughput of skin is low due to absorption and scattering. To overcome these difficulties, we have developed a high-brightness tunable laser system for measurements in the 2.0-2.5 microm wavelength range. The system is based on a 2.3 microm wavelength, strained quantum-well laser diode incorporating GaInAsSb wells and AlGaAsSb barrier and cladding layers. Wavelength control is provided by coupling the laser diode to an external cavity that includes an acousto-optic tunable filter. Tuning ranges of greater than 110 nm have been obtained. Because the tunable filter has no moving parts, scans can be completed very quickly, typically in less than 10 ms. We describe the performance of the present laser system and avenues for extending the tuning range beyond 400 nm.
authors.affiliation: Optical Science and Technology Center and the Department of Chemistry, 100 IATL, University of Iowa, Iowa City, Iowa 52242, USA. jonathon-olesberg@uiowa.edu
authors.forename: Jonathon T
authors.initials: JT
authors.lastname: Olesberg
authors.forename: Mark A
authors.initials: MA
authors.lastname: Arnold
authors.forename: Carmen
authors.initials: C
authors.lastname: Mermelstein
authors.forename: Johannes
authors.initials: J
authors.lastname: Schmitz
authors.forename: Joachim
authors.initials: J
authors.lastname: Wagner
mesh_terms: D001786:Blood Glucose / Q000032:analysis*; D015190:Blood Glucose Self-Monitoring / Q000295:instrumentation* / Q000379:methods; D004582:Electronics, Medical; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006801:Humans; D007834:Lasers; D015203:Reproducibility of Results; D012666:Semiconductors; D012680:Sensitivity and Specificity; D013055:Spectrophotometry, Infrared / Q000295:instrumentation* / Q000379:methods
chemical_list: D001786:Blood Glucose