Browsing by Author "Vural, Mert"

Filter results by typing the first few letters
Now showing 1 - 2 of 2
  • Thumbnail Image
    ItemOpen Access
    Bio-insprired optoelectronic digital nose for breath analysis
    (2011) Bayındır, Mehmet; Yıldırım, Adem; Yaman, Mecit; Vural, Mert
    A novel electronic nose device is presented that can be used in disease diagnostics by exhaled breath analysis. Exhaled breath contains more than a thousand organic compounds that can be analysed to insect various diseases and metabolic activity. The novel device is an electronic nose, based on photonic bandgap fibers that can selectively guide infrared radition inside a hollow core plastic fiber. Instead of a laser line source, a broadband balackbody source is used that exploits the filtering/ guiding properties of the fibers to scan the whole mid-infrared region, making it high selectivity of volatile organic compounds possible. In addition waveguiding inside the fiber enhances the electromagnetic radiation intensity, resulting in improved infrared absorption cross-section. The fiber electronic nose can be integrated and deployed as a portable electronics device to point-of-care institutes.
  • Thumbnail Image
    ItemOpen Access
    Hollow core photonic bandgap fibers for medical applications
    (2009) Vural, Mert
    The design, fabrication and characterization of photonic band gap (PBG) based optical polymer fibers is discussed. Unlike conventional total internal reflection (TIR) fibers, used primarily in telecommunications, PBG fibers can be made hollow core and can be used to guide infrared radiation of any wavelength, a property known as wavelength scalability. Since the electromagnetic radiation is transmitted in the hollow core of the fiber, the intrinsic absorption of the fiber core as well as the insertion Fresnel losses at front and end faces are avoided, giving rise to extraordinarily high power densities to be delivered. The fiber production line includes material characterization, and the design of nanoscale quarter wavestacks using common thermoplastic polymers (poly ether sulphone and poly ether imide) and chalcogenide glasses (As2S3, As2Se3, Ge15As25Se15Te45). The fiber preform is fabricated using rolling mechanism of thermally evaporated chalcogenide glasses on large area polymers. Subsequently, the fiber preforms are thermally drawn to obtain nano-structured PBG fibers.Two different fibers are designed and produced, signifying wavelength scalability of the overall process, for the widely used holmium (Ho:YAG) and carbon dioxide (CO2) medical lasers. The transmission characteristics of the fibers proved that they can be used to safely deliver 15Wlaser power, along a 3 meter fiber with external diameter of 1.5 mm and hollow core diameter of 0.5 mm, corresponding to a laser power density of 1kW/cm2 with a loss of -10dB/m. The PBG fibers are expected to be widely used in high precision surgical laser for incision, photoablation and coagulation where infrared radiation is the radiation of choice for its superior laser-tissue interaction properties.