RT - Journal Article T1 - Tip sensor probe for changing refractive index measurement in small volumes JF - ijop YR - 2014 JO - ijop VO - 8 IS - 2 UR - http://ijop.ir/article-1-172-en.html SP - 105 EP - 111 K1 - etching K1 - intra-cellular sensor K1 - optical fiber tip K1 - refractive index K1 - tapered optical fiber AB - 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. LA eng UL http://ijop.ir/article-1-172-en.html M3 ER -