Fiber-optic surface plasmon resonant sensor with low-index anti-oxidation coating

• 来源期刊: 中国光学快报（英文版）
• 年，卷（期）: 2011,（11）
• 页码范围: 22-25
• 页数: 4页
• 语种: 英文
• DOI: 10.3788/COL201109.100605

摘要

A multimode fiber-optic surface plasmon resonance (SPR) sensor with a MgF2 film as a modulated layer is studied.The fiber-optic SPR sensor is investigated theoretically,specifically the influence of the dielectric protecting layer,using a four-layer model.The sensor is then fabricated with the optimal parameters suggested by the theoretical simulation.The sensor has a high sensitivity in the analyte refractive index (RI) range of 1.33-1.40.The best sensitivity of 4 464 nm/RIU is achieved in the experiment.The use of dielectric film (MgF2) can not only modulate the resonance wavelength of the sensor,but also protect the silver film from oxidation.Surface plasmon resonance (SPR) is a kind of coherent oscillation between the free electrons at a metal/dielectric interface and the optical wave.The hybridized excitation,called surface plasmon polariton (SPP),is the electromagnetic excitation that propagates along the interface as a longitudinal wave.At a given wavelength and angle that satisfy the wave-vector matching condition,the incident light will be intensively absorbed.Due to its high sensitivity to the refractive index (RI) of the adjacent material,the SPR phenomenon was firstly applied to gas detection in 1983[1].The SPR sensing technology has been widely used in the detection of biological and chemical analytes,environmental monitoring,and medical diagnostics in the past two decades[2-5].