Two optofluidic devices for the refractive index measurement of small volume of fluids

Kuo Sheng Chao, Tsung Yu Lin, Ruey Jen Yang

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)


Two simple optofluidic devices based on a microprism and a refraction channel, respectively, are proposed for measuring the refractive index of fluids. The microprism chip consists of an optical waveguide channel and a single triangular chamber filled with the test fluid, while the refraction channel chip consists of a single turning channel which functions as a liquid-core/solidcladding optical waveguide. In both chips, the refractive index of the test fluid is calculated from a CCD image of the refracted ray in accordance with simple geometrical optics principles. The experimental results show that the refraction channel chip provides a more accurate measurement performance than the microprism chip; particularly for colloidal samples. However, the refraction channel chip is suitable only for the measurement of fluids with a refractive index greater than that of the chip substrate. Overall, the results presented in this study show that both devices provide a simple, low cost and effective means of determining the refractive index of a wide range of common test fluids with nano-liter volume.

Original languageEnglish
Pages (from-to)697-704
Number of pages8
JournalMicrofluidics and Nanofluidics
Issue number5
Publication statusPublished - 2012 Mar

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Materials Chemistry


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