title: A compact fiber-optic probe-based singlet oxygen luminescence detection system.
abstract: This paper presents a novel compact fiberoptic based singlet oxygen near-infrared luminescence probe coupled to an InGaAs/InP single photon avalanche diode (SPAD) detector. Patterned time gating of the single-photon detector is used to limit unwanted dark counts and eliminate the strong photosensitizer luminescence background. Singlet oxygen luminescence detection at 1270 nm is confirmed through spectral filtering and lifetime fitting for Rose Bengal in water, and Photofrin in methanol as model photosensitizers. The overall performance, measured by the signal-to-noise ratio, improves by a factor of 50 over a previous system that used a fiberoptic-coupled superconducting nanowire single-photon detector. The effect of adding light scattering to the photosensitizer is also examined as a first step towards applications in tissue in vivo.
authors.affiliation: Division of Electronic and Nanoscale Engineering, University of Glasgow, UK.
authors.forename: Nathan R
authors.initials: NR
authors.lastname: Gemmell
authors.affiliation: Institute of Photonics and Quantum Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, UK.
authors.forename: Aongus
authors.initials: A
authors.lastname: McCarthy
authors.affiliation: Department of Radiation Oncology, University of Pennsylvania, USA.
authors.forename: Michele M
authors.initials: MM
authors.lastname: Kim
authors.affiliation: University Health Network/University of Toronto, Canada.
authors.forename: Israel
authors.initials: I
authors.lastname: Veilleux
authors.affiliation: Department of Radiation Oncology, University of Pennsylvania, USA.
authors.forename: Timothy C
authors.initials: TC
authors.lastname: Zhu
authors.affiliation: Institute of Photonics and Quantum Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, UK.
authors.forename: Gerald S
authors.initials: GS
authors.lastname: Buller
authors.affiliation: University Health Network/University of Toronto, Canada.
authors.forename: Brian C
authors.initials: BC
authors.lastname: Wilson
authors.affiliation: Division of Electronic and Nanoscale Engineering, University of Glasgow, UK.
authors.forename: Robert H
authors.initials: RH
authors.lastname: Hadfield
mesh_terms: D005336:Fiber Optic Technology; D049449:Luminescence; D017319:Photosensitizing Agents / Q000737:chemistry*; D059629:Signal-To-Noise Ratio; D026082:Singlet Oxygen / Q000032:analysis*
chemical_list: D017319:Photosensitizing Agents; D026082:Singlet Oxygen
keywords: fluorescence; photon counting; quantum optics; singlet oxygen