title: Giant sensitivity of long period gratings in transition mode near the dispersion turning point: an integrated design approach.
abstract: We report an original design approach based on the modal dispersion curves for the development of long period gratings in transition mode near the dispersion turning point exhibiting ultrahigh refractive index sensitivity. The theoretical model predicting a giant sensitivity of 9900 nm per refractive index unit in a watery environment was experimentally validated with a result of approximately 9100 nm per refractive index unit around an ambient index of 1.3469. This result places thin film coated LPGs as an alternative to other fiber-based technologies for high-performance chemical and biological sensing applications.
authors.affiliation: Optoelectronics Division, Engineering Department, University of Sannio, C.so Garibaldi 107, 82100 Benevento, Italy.
authors.forename: Pierluigi
authors.initials: P
authors.lastname: Pilla
authors.forename: Cosimo
authors.initials: C
authors.lastname: Trono
authors.forename: Francesco
authors.initials: F
authors.lastname: Baldini
authors.forename: Francesco
authors.initials: F
authors.lastname: Chiavaioli
authors.forename: Michele
authors.initials: M
authors.lastname: Giordano
authors.forename: Andrea
authors.initials: A
authors.lastname: Cusano
mesh_terms: D008962:Models, Theoretical; D055620:Optical Phenomena; D013057:Spectrum Analysis