Tunable laser diode system for noninvasive blood glucose measurements.

Optical Science and Technology Center and the Department of Chemistry, 100 IATL, University of Iowa, Iowa City, Iowa 52242, USA.
Applied Spectroscopy (Impact Factor: 1.94). 01/2006; 59(12):1480-4. DOI: 10.1366/000370205775142485
Source: PubMed

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.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Diabetes Mellitus is a common chronic disease that has become a public health issue. Continuous glucose monitoring improves patient health by stabilizing the glucose levels. Optical methods are one of the painless and promising methods that can be used for blood glucose predictions. However, having accuracies lower than what is acceptable clinically has been a major concern. Using lasers along with multivariate techniques such as Partial Least Square (PLS) can improve glucose predictions. This research involves investigations for developing a novel optical system for accurate glucose predictions, which leads to the development of a small, low power, implantable optical sensor for diabetes patients.
    Proc SPIE 08/2009;
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A broadband external cavity tunable laser is realized by using a broad-emitting spectral InAs/GaAs quantum dot (QD) gain device. A tuning range of 69 nm with a central wavelength of 1056 nm, is achieved at a bias of 1.25 kA/cm2 only by utilizing the light emission from the ground state of QDs. This large tunable range only covers the QD ground-state emission and is related to the inhomogeneous size distribution of QDs. No excited state contributes to the tuning bandwidth. The application of the QD gain device to the external cavity tunable laser shows its immense potential in broadening the tuning bandwidth. By the external cavity feedback, the threshold current density can be reduced remarkably compared with the free-running QD gain device.
    Chinese Physics B 01/2010; 19(1):018104. · 1.15 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Energy-transfer processes in a Yb:Tm:YLF laser under 685 and 960 nm pumping have been quantitatively studied and computer simulations considering the full rate-equation scheme up to the 1 G 4 level have been performed. The 2.3 μm laser efficiency has been simulated under simultaneous diode pumping at both wavelengths. Optimized values of 685–960 nm pump power ratio for typical laser cavity parameters were derived to achieve maximum output power under constant pump power. Laser experiments performed at 2.3 μm are in agreement with these results. The achieved output power of 620 mW is the highest reported so far.
    Journal of Optics A Pure and Applied Optics 01/2008; 10:104009-7. · 1.92 Impact Factor

Full-text (2 Sources)

Available from
May 19, 2014