International Journal of

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The average velocity of water flow has been simultaneously measured with fluorescent and speckle imaging methods. The measured velocities with two methods are in good agreement with each other and it confirms that the speckle imaging method can be used as a confident method to measure the velocity of water flow in a dry leaf. Also the velocity of water flow through thick and thin xylems of a leaf can be measured with speckle imaging method and the ratio of thick xylem’s radius to thin xylem’s radius can be estimated with this method. Also the ratio was measured by monitoring the cross section of the leaf. The two measurements were in agreement.

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In this paper, a tapered tip optical fiber probe sensor for localized refractive index (RI) measurements is presented. This sensor’s interaction with analytes is confined to a few micro-meters which makes it a promising candidate for in-vivo or even intra-cellular RI monitoring. This tapered tip was simply fabricated by etching optical fiber with hydrofluoric acid to a conic shape with a sub-micrometer aperture. The sensor was calibrated for RI measurement using different concentrations of NaCl in water. Limit of detection of 6.7×10^-5 RIU was achieved for this low-cost sensor.