Fig. 2From: Tapered photonic crystal fibers coated with ultra-thin films for highly sensitive bio-chemical sensing(a)Transmission spectra of the sensor at different concentrations of NaCl, (b) linear fit of the sensor response for different concentrations of NaCl with RI between 1.30864 and 1.32014 (reprinted with permission from Ref. [7], IEEE/OSABack to article page