Effect of taper geometries and launch angle on evanescent wave penetration depth in optical fibers

Mohammad Ahmad, Larry L. Hench

Research output: Contribution to journalArticle

89 Citations (Scopus)


A large penetration depth of an evanescent wave is the key to success for developing an ultra high-resolution fiber-based evanescent wave biosensor. Tapering the fiber and launching light at an angle has the potential of increasing the penetration depth of evanescent wave manifolds. The effects of tapering, launch angle and taper length of the fiber have been explored in detail using a ray-tracing model to calculate the highest possible penetration depth of the evanescent field. Evanescent wave penetration depths of the order of the size of living cells have been achieved by optimizing the parameters relating geometry of tapered fibers.

Original languageEnglish
Pages (from-to)1312-1319
Number of pages8
JournalBiosensors and Bioelectronics
Issue number7
Publication statusPublished - Jan 15 2005



  • Biological and medical applications
  • Biosensors
  • Cells
  • Design and operation
  • Evanescent wave
  • Fluorescence
  • Lasers
  • Taper fiber

ASJC Scopus subject areas

  • Biotechnology
  • Biophysics
  • Biomedical Engineering
  • Electrochemistry

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