Browsing by Author "Tatam, Ralph P."

Browsing by Author "Tatam, Ralph P."

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  • Zakaria, Ryadh Abdullah (Cranfield University, 2010-03)
    In this thesis the development of a single pass non-dispersive infrared (NDIR) CO2 gas sensor with a path length of 30mm and with a lowest level CO2 detectivity of 20 ppm is described. A single pass NDIR CO2 sensor was ...
  • Murphy, Richard P.; James, Stephen W.; Tatam, Ralph P. (International Society for Optical Engineering; 1999, 2007-12-31)
    The concept of nested fibre optic long period grating (LPG) based interferometers is introduced. A number of in-series, identical LPGs may be used to form a set of nested, multiplexed Mach-Zehnder interferometers that ...
  • Davenport, John; Hodgkinson, Jane; Saffell, John R.; Tatam, Ralph P. (Optical Society of America, 2015-08-17)
    We present the results of a detailed analysis of the noise behavior of two CCD spectrometers in common use, an AvaSpec-3648 CCD UV spectrometer and an Ocean Optics S2000 Vis spectrometer. Light sources used include a ...
  • Hodgkinson, Jane; Smith, R.; Ho, Wah On; Saffell, John R.; Tatam, Ralph P. (Elsevier Science B.V., Amsterdam., 2013-09-30)
    Non-dispersive infra-red (NDIR) gas detection has enjoyed widespread uptake as a result of development of devices in the standard miniature format for gas sensors, consisting of a cylinder with external dimensions of 20mm ...
  • Davenport, J. J.; Hodgkinson, Jane; Saffell, J. R.; Tatam, Ralph P. (IEEE, 2018-01-25)
    We describe a simple method for detecting formaldehyde using low resolution non-dispersive UV absorption spectroscopy. A two channel sensor was developed, making use of a strong absorption peak at 339 nm and a neighbouring ...
  • Urrutia, Aitor; Bojan, Kartheka; Marques, L.; Mullaney, Kevin; Goicoechea, Javier; James, Stephen W.; Clark, M.; Tatam, Ralph P.; Korposh, Sergiy (Hindawi Publishing Corporation, 2016-08-08)
    In this work, novel protein sensors based on tapered optical fibres modified with Au coatings deposited using two different procedures are proposed. Au based coatings are deposited onto a non-adiabatic tapered optical fibre ...
  • Asmari, Abdullah Shah (Cranfield University, 2015)
    Tuneable diode laser absorption spectroscopy (TDLAS) based gas sensors are widely used for trace gas detection for their high selectivity and sensitivity. The laser source used in TDLAS requires a narrow line width in ...
  • Charrett, Thomas O. H.; Tatam, Ralph P. (SPIE, 2015)
    This paper describes an extended theory of the displacement of the objective speckle pattern resulting from displacement and/or deformation of a coherently illuminated diffuse object where the influence of the surface shape ...
  • Charrett, Thomas O. H.; Tatam, Ralph P. (Optical Society of America, 2014-10-10)
    This paper describes an extended and improved theory of the displacement of the objective speckle pattern resulting from displacement and/or deformation of a coherently illuminated diffuse object. Using the theory developed ...
  • Francis, Daniel; Charrett, Thomas O. H.; Waugh, L.; Tatam, Ralph P. (Osa Optical Society of America, 2012-05-31)
    Speckle velocimetry is investigated as a means of determining odometry data with potential for application on autonomous robotic vehicles. The technique described here relies on the integration of translation measurements ...
  • Chehura, Edmon; Dell'Anno, Giuseppe; Huet, Tristan; Staines, Stephen E.; James, Stephen W.; Partridge, Ivana K.; Tatam, Ralph P. (Institute of Physics, 2014-05-20)
    Dynamic loadings induced on a tufting needle during the tufting of dry carbon fibre preform via a commercial robot-controlled tufting head were investigated in situ and in real-time using optical fibre Bragg grating (FBG) ...
  • Casaubieilh, P.; Ford, Helen D.; James, Stephen W.; Tatam, Ralph P. (International Society for Optical Engineering; 1999, 2005-12-31)
    We report the investigation of a Fizeau interferometer-based OCT system. A secondary processing interferometer is necessary in this configuration, to compensate the optical path difference formed in the Fizeau ...
  • Chowdhury, Sahar A.; Correia, Ricardo N.; Francis, Daniel; Brooks, Simon J.; Jones, Benjamin J. S.; Thompson, Alexander W. J.; Hodgkinson, Jane; Tatam, Ralph P. (Institute of Electrical and Electronics Engineers, 2015-06-15)
    A self-referenced optical fiber refractometer using a ball lens as a sensor head has been developed and characterized. A 350-μm ball lens created at the tip of a single mode fiber has been coated with a 40-nm optically ...
  • Gagliardi, G.; Salza, M.; Ferraro, P.; Chehura, Edmon; Tatam, Ralph P.; Gangopadhyay, T. K.; Ballard, N.; Paz-Soldan, D.; Barnes, J. A.; Loock, H-P; Lam, TT-Y; Chow, J. H.; De Natale, P. (MDPI AG, 2010-03-05)
    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 ...
  • Casaubieilh, P.; Ford, Helen D.; Tatam, Ralph P. (SPIE - International Society for Optics and Photonics, 2004-06-09)
    An optical fibre, Fizeau configuration Optical Coherence Tomography (OCT) system is presented in this paper. The interferometer is formed between the distal end of the sample-arm fibre and the sample itself. This ensures ...
  • Buggy, Stephen J.; Chehura, Edmon; James, Stephen W.; Tatam, Ralph P. (Institute of Physics, 2007-06-01)
    The use of fibre grating refractometers as a means of monitoring the cure of a UVcured epoxy resin is presented. The wavelength shift of the attenuation bands of a long period grating and the spectral response of a tilted ...
  • Topliss, Stephen M.; James, Stephen W.; Davis, Frank; Higson, Seamus P. J.; Tatam, Ralph P. (Elsevier Science B.V., Amsterdam., 2010-01-07)
    The chemical sensing capabilities of an optical fibre long period grating (LPG) coated with a functional material are explored. The LPG period and coating thickness are chosen such that the mode transition region, ...
  • Hromadka, Jiri; Tokay, Begum; James, Stephen W.; Tatam, Ralph P.; Korposh, Sergiy (Elsevier, 2015-07-09)
    An optical fibre long period grating (LPG) modified with a thin film of ZIF-8, a zeolitic immidazol framework material and a subgroup of metal organic framework family, was employed for the detection of organic vapours. ...
  • Topliss, Stephen M. (Cranfield University, 2011-06)
    The dual resonant response of long period fibre gratings (LPG) operating near the phase matching turning point to the deposition of nanostructured coatings is explored. A broad range of LPGs have been fabricated with grating ...
  • Ford, Helen. Diana (Cranfield University, 1994-03)
    Polarisation-based wavelength-division multi-/demulti-plexers (WDMs) and filters have been designed, constructed and evaluated. These are compact devices made from single-mode optical fibre possessing high linear ...