Noninvasive blood flow measurement using speckle signals from a self-mixing laser diode: in vitro and in vivo experiments

Şahin Kaya Özdemir, Shigenobu Shinohara, Sotetsu Takamiya, Hirofumi Yoshida

Research output: Contribution to journalArticle

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A semiconductor laser speckle velocimeter that uses the self-mixing effect is studied for noninvasive relative blood flow measurements. The random modulation of intensity and spectra of the laser diode caused by the backcoupling of the scattered light from the red blood cells into the laser cavity is detected as a speckle signal with a photodiode inside the laser package. The autocorrelation of this self-mixing speckle signal gives information on the flow velocity of the blood. The proposed method is elucidated with in vitro and in vivo experiments. The results of these measurements are given together with a discussion of dependence of speckle signal of a self-mixing laser diode (SMLD) on various parameters such as velocity, hematocrit level of blood, and background reflectance of blood suspension.

Original languageEnglish (US)
Pages (from-to)2574-2580
Number of pages7
JournalOptical Engineering
Issue number9
Publication statusPublished - Sep 1 2000


All Science Journal Classification (ASJC) codes

  • Atomic and Molecular Physics, and Optics
  • Engineering(all)

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