Optical Fibre Sensors This research theme is devoted to the creation and fabrication of chemical sensors based on a range of sensing platforms modified with advanced functional nano-materials for applications in fields ranging from healthcare  and environmental monitoring  to food and beverage quality assessment . Group is working on the development of the optical fibre sensors based on the long period gratings (LPGs) [4-10], fibre Bragg gratings (FBGs) , tapered optical fibres , evanescent wave spectroscopy  and refection optrodes  The principle of operation of the optical fibre sensors based on various platforms is explained in Figure 1.
Figure 1: Optical fibre sensing platforms. Figure 2: Fibre Bragg gratings.
Fibre optic grating based sensors, Fibre Bragg Gratings, (FBGs), and long period gratings, LPGs have been extensively investigated for the measurement of physical and chemical parameters. An FBG consists of a periodic modulation of the refractive index of the core of the optical fibre with a period of the order of the wavelength of light and acts to reflect light of a specific wavelength (equal to twice the optical period of the grating) back along the fibre, Figure 2. The lengths of the FBG can vary from 0.5 mm to 20 mm
. F. U. Hernandez, S. P. Morgan, B. R. Hayes-Gill, D. Harvey, W. Kinnear, A. Norris, D. Evans, J. G. Hardman and S. Korposh “Characterisation and Use of a Fibre Optic Sensor based on PAH/SiO2 Film for Humidity Sensing in Ventilator Care Equipment”, IEEE Transactions on Biomedical Engineering, 2016, in press.
. R. Selyanchyn, S. Korposh, S. Wakamatsu, S.-W. Lee, “Simultaneous monitoring of humidity and chemical changes using quartz crystal microbalance sensors modified with nano-thin films”, Analytical Sciences, 27, 2011, 1-6.
. S. Korposh, R. Selyanchyn, S. W. James, R. P Tatam, and S.-W. Lee “Identification and quality assessment of beverages using a long period grating fibre-optic sensor modified with a mesoporous thin film”, Sensing and Bio-Sensing Research, 2014, 1, 26–33.
. T. Wang, W. Yasukochi, S. Korposh, S. W. James, R. P. Tatam, S.-W. Lee, “A long period grating optical fiber sensor with nano-assembled porphyrin layers for detecting ammonia gas”, Sensors and Actuators B: Chemical, 2016, in press, ISSN 0925-4005, http://dx.doi.org/10.1016/j.snb.2016.01.058.
. J. Hromadka, B. Tokay, S. James, R. Tatam, S. Korposh, Optical fibre long period grating gas sensor modified with metal organic framework thin films, Sensords and Actuators , 2015, 221, 891–899.
. S. Korposh, I. Chianella, A. Guerreiro, S. Caygill, S. A. Piletsky, S. W. James and R. P. Tatam, “Selective vancomycin detection using optical fibre long period gratings functionalised with molecularly imprinted polymer nanoparticles”, Analyst, 2014, 139, 2229-2236, DOI:10.1039/C3AN02126B.
. S. W. James, S. Korposh, S.-W. Lee and R. P Tatam, “A long period grating-based chemical sensor insensitive to the influence of interfering parameters”, Optics Express, 2014, 22(7), 8012-23. doi: 10.1364/OE.22.008012.
. T. Wang, S. Korposh, S. James, R. Tatam, and S.-W. Lee, “Optical fibre long period grating sensor with a polyelectrolyte alternate thin film for gas sensing of amine odors”, Sensors and Actuators B: Chemical, 2013, 185, 117-124.
. S. Korposh, R. Selyanchyn, W. Yasukochi, S.-W. Lee, S. James, R. Tatam, “Optical fibre long period grating with a nanoporous coating formed from silica nanoparticles for ammonia sensing in water”, Materials Chemistry and Physics, 133, 2012, 785–792.
. S. Korposh, S.-W. Lee, S. W. James, R. P. Tatam, “Refractive index sensitivity of fibre optic long period gratings coated with SiO2 nanoparticle mesoporous thin films”, Meas. Sci. Tech., 22, 2011, 075208 (10p).
. F.U. Hernandez, R. Correia, S. Korposh, S.P. Morgan, B. R. Hayes-Gill, S.W. James, D. Evans, A. Norris, Measurements of endotracheal tube cuff contact pressure using fibre Bragg gratings, Proc. SPIE 9634, 24th International Conference on Optical Fibre Sensors, 963435 (September 28, 2015); doi:10.1117/12.2195118.
. R. Jarzebinska, S. Korposh, S. James, W. Batty, R. Tatam, S.-W. Lee,”Optical gas sensor fabrication based on porphyrin-anchored electrostatic self-assembly onto tapered optical fibres", Analytical Letters, 45(10), 2012, 1297–1309.
. W. Yasukochi, T. Wang, S. Kodaira, S. Korposh, R. Selyanchyn, S.-W. Lee, “Ammonia gas detection using an optically sensitive hybrid organic-inorganic multilayer nanoporous film”, Advanced Science Letters, 2013, 19(2), 415–419(5).