Critical-angle-based sensor with improved figure of merit using dip detection

Ibrahim Watad, Mohamad A. Jabalee, Amir Aizen, Ibrahim Abdulhalim

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


It is demonstrated theoretically and experimentally that a one-dimensional photonic crystal (1D-PC) made of quarter waves stacked on top of a prism exhibits both TE and TM resonances that coincide with the critical angle θc when the 1D-PC is semi-infinite and with very little deviation from θc for a finite 1D-PC. As a refractive index (RI) sensor, it behaves as a total internal reflection sensor at θc with the advantage of detecting a narrow dip rather than an edge and enhanced figure of merit by increasing the number of periods in the 1D-PC. Using the diverging beam approach on an optical bench, a two channel sensor is demonstrated with a sensitivity of 120.9 deg/RIU and a detection limit of 1.9 × 10-5 RIU.

Original languageEnglish
Pages (from-to)4388-4391
Number of pages4
JournalOptics Letters
Issue number19
StatePublished - 1 Jan 2015

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics


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