Sensor Absorption Research Articles

Theoretical investigation of absorption and sensitivity of nano-plasmonic tapered fiber optic sensors

In this paper, a theoretical investigation for the performance a tapered fiber optic sensor based on surface plasmon resonance (SPR) is proposed. The tapered fiber optic sensor is considered for three different taper profiles, namely, linear, parabolic, and exponential-linear. The tapered fiber optic sensor is coated with thin nanoparticle metallic films. The nanoparticle metallic film consists of spherical metallic nanoparticles embedded in a host material. The performance has been analyzed in terms of sensitivity and absorption of the sensor. It is shown that sensitivity and absorption of sensors depends on parameters such as taper ratio, taper profile, nanoparticle film thickness, nanoparticle radius, sensing region length, fiber core diameter, and concentration of sensing layer.

Spectroscopic studies on a ‘turn-on’ fluorescent sensor for transition metals with selective ‘turn-off’ for mercury(II) ions

Spectroscopic studies on a dansyl-based fluorescent sensor N-(4-aminophenyl)-5-(dimethylamino)naphthalene-1-sulphonamide (1) and its interactions with transition metals are reported. The sensor's absorption and emission spectra exhibited different profiles at different polarities and pH values. Enhanced fluorescence was observed in the presence of chromium(III) ions in methanol, while the emission was quenched significantly in the presence of mercury(II) ions both in methanol and aqueous solution. The binding constants of 1 to chromium(III) in methanol and to mercury(II) ions in methanol and aqueous solution were calculated.