Time-resolved single photon spectroscopy through a single optical fibre for miniaturised medical probe design

Katjana Ehrlich*, H. Fleming, Sarah McAughtrie, A. Kufcsák, N. Krstajic, C. J. Campbell, R. K. Henderson, Kevin Dhaliwal, Robert R. Thomson, Michael George Tanner

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution

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We present a spectroscopic system and an optical fibre probe which enable the full exploitation of the temporal evolution and spectral information of a weak Raman signal against background fluorescence and intrinsic fibre Raman. The system consists of a single multimode fibre and a CMOS single-photon avalanche diode (SPAD) line sensor capable of resolving and histogramming the arrival times of photons for 256 pixels simultaneously, offering improved signal to background compared to a non-time resolved measurement modality. The capabilities of the system are tested for intrinsic Raman standards such as cyclohexane and for pH sensing with functionalised gold nanoshells exploiting surface enhanced Raman scattering (SERS). The nanoshells are functionalised with the pH responsive 4-mercaptobenzoic acid (MBA) enabling demonstration of wide range pH sensing with low excitation power (< 1 mW) and short acquisition times (10 s), achieving a measurement precision of ± 0.07 pH units.

Original languageEnglish
Title of host publicationBiophotonics
Subtitle of host publicationPhotonic Solutions for Better Health Care VI
EditorsJürgen Popp, Valery V. Tuchin, Francesco Saverio Pavone
ISBN (Electronic)9781510618978
ISBN (Print)9781510618961
Publication statusPublished - 17 May 2018

Publication series

NameProceedings of SPIE
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


  • Detector arrays
  • Fibre optic sensors
  • Photon counting
  • Raman spectroscopy
  • Surface-enhanced Raman scattering
  • Time-resolved spectroscopy

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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