Patent ID: 8048385

Claim:
A sensing chip for measuring a refractive index of a long-range surface plasmon polariton, having a thin metal film or a strip-like metal as well as an upper limiting layer and a lower limiting layer made of silicon-rich silica SiO x (where 0<x<2), SiO 2 or benzocyclobutene (BCB) and a dielectric buffer layer formed on the upper and lower surfaces thereof, wherein said dielectric buffer layer is made of silicon-rich silica SiO x (where 0<x<2) or silicon nitride SiN y (where 0<y<4/3), and attached onto a measurement groove of the metal thin film or the strip-like metal, the metal thin film or the strip-like metal and the buffer layer are sandwiched between said upper limiting layer and said lower limiting layer, and the upper layer surface of said upper limiting layer made of SiO x , SiO 2 or benzocyclobutene is perforated to form the measurement groove, all of the aforementioned structures are grown on an Si underlayer, a GaAs underlayer, an InP underlayer or an SiO 2 underlayer, and the sensing chip is arranged so that the refractive index of a long-range surface plasmon polariton is measured by forming a long-range surface plasmon polariton by performing excitation on an end face of said metal thin film or said strip-like metal, and measuring a refractive index change of a liquid in the measurement groove or an antigen-antibody reaction of an organism from a change in transmission loss of said long-range surface plasmon polariton and/or a change in a light spot size.