A D-type fiber biosensor based on surface-plasmon resonance (SPR) technology and heterodyne interferometry is presented. The sensing device is a single-mode optical fiber in which half the core is polished away and a thin-film layer of gold is deposited. We measure the phase-difference variations instead of the light intensity as in traditional SPR techniques. Therefore the accuracy and resolution of our method are very high. Its sensitivity can reach 2×10^-6 refractive-index units. The sensor has some merits, e.g., tunable high sensitivity, small size, lower cost, smaller sample volume, and suitability for in vivo testing. This novel method of a D-type fiber biosensor based on SPR technology and heterodyne interferometry is valuable for chemical, biological, and biochemical sensing, and the novel method of D-type fiber biosensing is a feasible means of study.
© 2005 Optical Society of America
Ming-Hung Chiu, Shinn-Fwu Wang, and Rong-Seng Chang, "D-type fiber biosensor based on surface-plasmon resonance technology and heterodyne interferometry," Opt. Lett. 30, 233-235 (2005)