NaCl ion detection using a silica toroid microcavity

Jiro Nishimura, Misako Kobayashi, Ryusuke Saito, Takasumi Tanabe

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)


An optical-microcavity-based sensor is an important building block for an optofluidics system, because it allows us to fabricate small devices with high sensitivity. Here we describe the detection of NaCl and pH in water using a silica toroid microcavity. First we demonstrate the detection of NaCl particles, and show that a detection sensitivity of 0.38mM is possible with a sample volume of 0.03 nl. Then, we report the detection of NaCl ions in liquid and demonstrate a sensitivity of 3.20 mM and also, in principle, the detection of pH with a sensitivity of 0.14 pH. Finally, we integrate a tapered optical fiber, a silica toroid microcavity, and a fluidic channel for future optofluidics applications.

Original languageEnglish
Pages (from-to)6391-6396
Number of pages6
JournalApplied Optics
Issue number20
Publication statusPublished - 2015 Jul 10


  • Microcavities
  • Optical sensing and sensors

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Engineering (miscellaneous)
  • Electrical and Electronic Engineering


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