title: Femtosecond laser micromachining of compound parabolic concentrator fiber tipped glucose sensors.
abstract: We report on highly accurate femtosecond (fs) laser micromachining of a compound parabolic concentrator (CPC) fiber tip on a polymer optical fiber (POF). The accuracy is reflected in an unprecedented correspondence between the numerically predicted and experimentally found improvement in fluorescence pickup efficiency of a Förster resonance energy transfer-based POF glucose sensor. A Zemax model of the CPC-tipped sensor predicts an optimal improvement of a factor of 3.96 compared to the sensor with a plane-cut fiber tip. The fs laser micromachined CPC tip showed an increase of a factor of 3.5, which is only 11.6% from the predicted value. Earlier state-of-the-art fabrication of the CPC-shaped tip by fiber tapering was of so poor quality that the actual improvement was 43% lower than the predicted improvement of the ideal CPC shape.
authors.affiliation: Technical University of Denmark, Denmark Technical University Fotonik, Department of Photonics Engineering, Lyngby, Denmark.
authors.forename: Hafeez Ul
authors.initials: HU
authors.lastname: Hassan
authors.affiliation: Cyprus University of Technology, Nanophotonics Research Group, Department of Electrical Engineering, Computer Engineering and Informatics, Limassol, Cyprus.
authors.forename: Amédée
authors.initials: A
authors.lastname: Lacraz
authors.affiliation: Cyprus University of Technology, Nanophotonics Research Group, Department of Electrical Engineering, Computer Engineering and Informatics, Limassol, Cyprus.
authors.forename: Kyriacos
authors.initials: K
authors.lastname: Kalli
authors.affiliation: Technical University of Denmark, Denmark Technical University Fotonik, Department of Photonics Engineering, Lyngby, Denmark.
authors.forename: Ole
authors.initials: O
authors.lastname: Bang
mesh_terms: D001774:Blood Chemical Analysis / Q000295:instrumentation* / Q000379:methods*; D001786:Blood Glucose / Q000032:analysis*; D007834:Lasers; D055616:Microtechnology; D055100:Optical Fibers
chemical_list: D001786:Blood Glucose