Sensitivity characteristics in nanosized coated long period gratings

Cusano, A.; Iadicicco, Agostino; Pilla, P.; Cutolo, A.; Giordano, M.; Campopiano, Stefania

doi:10.1063/1.2388885

Cited by 50 publications

(24 citation statements)

References 12 publications

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“…In fact, the presence of the nanocoating is able to strongly modify the sensitivity characteristics of a bare LPG in response to the SRI changes. The effects range from the well known sub-linear monotone behavior with maximum sensitivity for SRI close to that of the cladding, to a resonant behavior [8]. The key parameters that play a relevant role in determining the final sensing properties of the coated devices can be identified in: the maximum sensitivity (|d res /dSRI| max ), the transition index (SRI at maximum sensitivity) and in the bandwidth (SRI range evaluated at half maximum sensitivity).…”

Section: Resultsmentioning

confidence: 99%

Nanocoating effects on tapered long period fiber gratings

Pilla

Cusano

Cutolo

et al. 2007

Third European Workshop on Optical Fibre Sensors

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In this work, the experimental analysis of the response of nanocoated Tapered Long Period Gratings (TLPGs) to Surrounding Refractive Index (SRI) changes is presented. The modal transition is demonstrated to take place in this kind of devices and to be an effective method to improve their SRI sensitivity. The dip-coating method was carried out by an automated system and showed to be a reliable technique for the deposition of conformal coatings. A comparison with traditional UV-written LPGs revealed that a thicker overlay is necessary for the TLPG to tune the transition region in the same SRI range.

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Section: Resultsmentioning

confidence: 99%

Nanocoating effects on tapered long period fiber gratings

Pilla

Cusano

Cutolo

et al. 2007

Third European Workshop on Optical Fibre Sensors

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“…The sensitivity characteristic of the coated LPG is drastically modified compared to the bare device. It has a resonant-like shape whose resonant peak can be tuned around the desired SRI by changing the overlay thickness (see Fig.1.b) 4 . Therefore the coated device can be used as a biochemical sensor if the overlay surface is properly functionalized in the way to specifically concentrate biochemicals at its surface which produce localized refractive index changes.…”

Section: Theoretical Backgroundmentioning

confidence: 99%

Long period gratings working in transition mode as a valuable technological platform for biosensing

et al. 2009

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In this work, we present preliminary results concerning the development of a platform for biochemical sensing based on overlayered Long Period Gratings (LPGs) working in transition mode. The surrounding medium refractive index (SRI) sensitivity of the bare device was greatly enhanced by means of the modal transition phenomenon which is enabled in LPGs with a nanoscale polymer overlay of higher refractive index than the cladding. This strategy was pursued to develop a sensitive tool for biochemical detection in aqueous solutions. Dip-coating was used to deposit thin layers of Polystyrene (PS) with different thicknesses on the same LPG to test the performances of the device in different working points of its modified sensitivity characteristic. The PS overlay surface was modified through adsorption of biotinylated bovin serum albumin (BBSA). Adsorption dynamic of BBSA was observed by on-line monitoring the shift of the LPGs attenuation bands. In the same way also a subsequent steptavidin (SA) binding dynamic on the byotinilated sites of the adsorbed proteins was recorded. Several washing cycles between the steps showed a rather stable immobilization of the protein monolayers. Experimental results show that overlayered LPGs are among the most sensitive refractive index transducers to be employed in biochemical detection and that wide margins of further optimization exist.

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“…7, the LPG's index sensitivity is fairly low for ambient index values from 1.33 to 1.39. RI sensitivity can be considerably increased by reducing cladding diameter in grating region [30] or depositing nanoscale overlays on LPGs that have higher RI compared to the cladding one [31].…”

Section: Refractive Index Characterizationmentioning

confidence: 99%