Design of ultra-sensitive biosensor applying surface plasmon resonance to a triangular resonator

We propose an ultra-sensitive integrated photonic sensor structure using an InP-based triangular resonator, in which a surface plasmon resonance (SPR) gold film is applied on a total internal reflection mirror. We have analyzed and optimized the triangular resonator sensor structure with an extremely small SPR mirror sensing area of 3.3 x 0.35 mu m(2). Due to the large phase shift in the SPR mirror, a significantly enhanced sensitivity of 930 nm/RIU (refractive index unit) and the maximum peak shift of half free spectral range have been obtained at the SPR angle of 24.125 degrees with Au thickness of 33.4 nm for the change of the refractive index Delta n = 1x10(-3). This value is larger than the previous largest value in micro resonator-type biosensors. Moreover, the proposed triangular resonator sensor can be easily made in a micro structure with optical source integration. (C) 2012 Optical Society of America