Now showing items 21-40 of 60

    • Chemical Sensing Using a Polymer Coated Long-Period Fiber Grating Interrogated by Ring-Down Spectroscopy 

      Barnes, Jack A.; Brown, Robert Stanley; Cheung, A.H.; Dreher, Marian; Mackey, G.; Loock, Hans-Peter (2016-03-15)
      An etched long-period grating was used as a refractive index sensor for vapours of four volatile organic compounds, i.e. m-xylene, cyclohexane, trichloroethylene and commercial gasoline. The sensitivity to the vapours was ...
    • Detection of Lead Contamination of Water and VOC Contamination of Air Using SOI Micro-Optical Devices 

      Saunders, J.; Dreher, Marian; Crudden, M. Cathleen; Du, J.; Loock, Hans-Peter; Xu, D.X; Densmore, A.; Ma, R.; Janz, S.; Vachon, M.; Lapointe, J.; Delâge, A.; Schmid, J.; Cheben, P. (2016-03-17)
      Micro-photonic SOI Mach-Zehnder interferometers were coated with solid-phase micro-extraction materials derived from polydimethylsiloxane to enable sensing of volatile organic compounds of the BTEX class in air. A different ...
    • Musical Instrument Recordings Made With a Fiber Fabry–Perot Cavity: Photonic Guitar Pickup 

      Ballard, Nicholas; Paz-Soldan, Daniel; Kung, Peter; Loock, Hans-Peter (2016-03-17)
      A 1 cm long, low-finesse fiber-optic cavity was used as a transducer for the vibrations of the soundboard of an acoustic guitar and of a violin. The reflected light is detected and then amplified and recorded using ...
    • Absorption Detection Using Optical Waveguide Cavities 

      Loock, Hans-Peter; Barnes, Jack A.; Gagliardi, Gianluca; Runkai Li, Runkai; Oleschuk, Richard; Wächter, Helen (2016-03-18)
      Cavity ring-down spectroscopy is a spectroscopic method that uses a high quality optical cavity to amplify the optical loss due to the light absorption by a sample. In this presentation we highlight two applications of ...
    • Chemical Sensing Using Fiber Cavity Ring-Down Spectroscopy 

      Waechter, Helen; Litman, Jessica; Cheung, Adrienne H.; Barnes, Jack A.; Loock, Hans-Peter (2016-03-18)
      Waveguide-based cavity ring-down spectroscopy (CRD) can be used for quantitative measurements of chemical concentrations in small amounts of liquid, in gases or in films. The change in ring-down time can be correlated to ...
    • Recording the Sound of Musical Instruments with FBGs: the Photonic Pickup 

      Loock, Hans-Peter; Hopkins, W. Scott; Morris-Blair, Christine; Resendes, Rui; Saari, Jonathan; Trefiak, Nicholas R. (2016-03-18)
      Fiber Bragg gratings (FBGs) have previously found many applications as strain and vibration sensors. Here we demonstrate that they may also be employed as pickups for musical instruments and, specifically, for acoustic ...
    • Single-Mode Fiber Refractive Index Sensor Based on Core-Offset Attenuators 

      Tian, Zhaobing; Yam, Scott S.-H.; Loock, Hans-Peter (2016-03-18)
      Mach-Zehnder and Michelson interferometers using core-offset attenuators were demonstrated. As the relative offset direction of the two attenuators in the Mach-Zehnder interferometer can significantly affect the extinction ...
    • Loss Determination in Microsphere Resonators by Phase-Shift Cavity Ring-Down Measurements 

      Barnes, Jack A.; Carver, B.; Fraser, James M.; Gagliardi, G.; Loock, Hans-Peter; Tian, Zhaobing; Wilson, M.W.B.; Yam, Scott S.-H.; Yastrubshak, O. (2016-03-21)
      The optical loss of whispering gallery modes of resonantly excited microresonator spheres is determined by optical lifetime measurements. The phase-shift cavity ring-down technique is used to extract ring-down times and ...
    • Long-Period Gratings in Chemical Sensing 

      Barnes, Jack A.; Brown, R. Stephen; Cipot-Wechsler, Judy; Crudden, M. Cathleen; Du, Jenny; Loock, Hans-Peter; Plett, Krista (2016-03-21)
      A chemical sensor system consisting of a coated long period grating, which was spliced into a fiber loop cavity, has been prepared and characterized. Designer coatings based on polydimethylsiloxane and nanostructured ...
    • Measurements of Energy Partitioning in H2 Formation by Photolysis of Amorphous Water Ice 

      Yabushita, Akihiro; Hama, Tetsuya; Lida, Daisuke; Kawanaka, Noboru; Kawasaki, Masahiro; Watanabe, Naoki; Ashfold, Michael N. R.; Loock, Hans-Peter (2016-03-21)
      We demonstrate experimentally that photodissociation of amorphous solid water at 100 K results in formation of H2 molecules with an ortho/para ratio of gOPR = 3. Two distinct mechanisms can be identified: endothermic ...
    • Visual Observation of Redistribution and Dissolution of Palladium During the Suzuki–Miyaura Reaction 

      MacQuarrie, S.; Horton, J. Hugh; Barnes, Jack A.; McEleney, Kevin; Loock, Hans-Peter; Crudden, M. Cathleen (2016-03-21)
      Now you see it, now you don't: A specially designed reactor that heats only a small area of Pd foil during a Suzuki-Miyaura coupling permits observation of the surface changes during the reaction. Dissolution of Pd occurs ...
    • Refractive Index Sensor Based On An Abrupt Taper Michelson Interferometer In a Single-Mode Fiber 

      Tian, Zhaobing; Yam, Scott S.-H.; Loock, Hans-Peter (2016-03-21)
      A simple refractive index sensor based on a Michelson interferometer in a single-mode fiber is constructed and demonstrated. The sensor consists of a single symmetrically abrupt taper region in a short piece of single-mode ...
    • Optical Fiber Sensing Based on Reflection Laser Spectroscopy 

      Gagliardi, G.; Salza, M.; Ferraro, P.; Chehura, E.; Tatam, R.P.; Gangopadhyay, T.K.; Ballard, Nicholas; Paz-Soldan, Daniel; Barnes, Jack A.; Loock, Hans-Peter; Lam, T.T.; Chow, J.H.; De Natale, Paolo (2016-03-22)
      An overview on high-resolution and fast interrogation of optical-fiber sensors relying on laser reflection spectroscopy is given. Fiber Bragg-gratings (FBGs) and FBG resonators built in fibers of different types are used ...
    • State-Selective Photodissociation Dynamics of Formaldehyde: Near Threshold Studies of the H+HCO Product Channel 

      Hopkins, W. Scott; Loock, Hans-Peter; Cronin, Brid; Nix, Michael G. D.; Devine, Adam L.; Dixon, Richard N.; Ashfold, Michael N. R. (2016-03-22)
      The laser-induced photodissociation of formaldehyde in the wavelength range 309<λ<330nm 309<λ<330nm has been investigated using H (Rydberg) atom photofragment translational spectroscopy. Photolysis wavelengths corresponding ...
    • Time-Resolved Photoacoustic Spectroscopy Using Fiber Bragg Grating Acoustic Transducers 

      Yang, Qingxin; Barnes, Jack A.; Loock, Hans-Peter; Pedersen, David (2016-03-22)
      An acoustic transducer based on a fiber Bragg grating (FBG) is presented and characterized for use in time-resolved laser-induced photoacoustic spectroscopy (PAS) on solid samples. The photoacoustic wave was generated by ...
    • Ring-Down Absorption Spectroscopy for Analytical Microdevices 

      Loock, Hans-Peter (2016-03-22)
      Ring-down absorption spectroscopy is an emerging ‘‘label-free’’ detection method for analytical microdevices, such as micrototal analysis systems (l-TAS). Developed from the related gas-phase cavity ring-down absorption ...
    • Proton Formation in 2+1 Resonance Enhanced Multiphoton Excitation of HCl and HBr via „=0… Rydberg and Ion-Pair States 

      Romanescu, Constantin; Loock, Hans-Peter (2016-03-22)
      Molecular beam cooled HCl was state selected by two-photon excitation of the V (1) summation operator(0(+)) [v=9,11-13,15], E (1) summation operator(0(+)) [v=0], and g (3) summation operator(-)(0(+)) [v=0] states through ...
    • Fiber-Optic Ring-Down Spectroscopy Using a Tunable Picosecond Gain-Switched Diode Laser 

      Andachi, M.; Nakayama, T.; Kawasaki, M.; Kurokawa, S.; Loock, Hans-Peter (2016-03-23)
      Visible and near-infrared laser light pulses were coupled into two different types of optical fiber cavities. One cavity consisted of a short strand of fiber waveguide that contained two identical fiber Bragg gratings. ...
    • Photoelectron Imaging Following 2 þ 1 Multiphoton Excitation of HBr 

      Romanescu, Constantin; Loock, Hans-Peter (2016-03-29)
      The photodissociation and photoionization dynamics of HBr via low-n Rydberg and ion-pair states was studied by using 2 + 1 REMPI spectroscopy and velocity map imaging of photoelectrons. Two-photon excitation at about 9.4–10 ...
    • Absorption Measurements in Microfluidic Devices Using Ring-Down Spectroscopy 

      Trefiak, Nicholas R.; Barnes, Jack A.; Rask, Fiona; Courtney, Daniel G.; Walford, Richard; Li, Runkai; Oleschuk, Richard; Loock, Hans-Peter (2016-03-29)
      When monitoring separation events in microfluidic devices, one frequently needs to detect small amounts of analyte in picolitre sized volumes with a time response of milliseconds. Fluorescence detection is typically the ...