In situ monitoring of pH level with fiber optic evanescent field spectroscopy

Masoud Ghandehari, Cristian S. Vimer

Research output: Contribution to journalArticlepeer-review


Fiber optic evanescent field spectroscopy for in situ monitoring of pH levels is presented. Cladding of plastic clad silica fiber is replaced with polymethyl methacrylate doped with pH sensitive chromoionophores. The chromoionophores include methyl red, thymol blue, and thymolphtalein for pH in acidic, neutral and basic environments, respectively. The evanescent wave is used to selectively excite the indicator molecules within the fiber cladding for sampling aqueous media surrounding the fiber.

Original languageEnglish (US)
Pages (from-to)611-616
Number of pages6
JournalNDT and E International
Issue number8
StatePublished - Dec 2004


  • Concrete durability
  • Corrosion sensing
  • Infrastructure monitoring
  • Materials health monitoring
  • Optical fiber sensors

ASJC Scopus subject areas

  • General Materials Science
  • Condensed Matter Physics
  • Mechanical Engineering


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