Optics and Photonics Society of Iran

Surface plasmon resonance (SPR) sensors are interesting because of their high sensitivity, resolution, accuracy and fast optical response. For exciting the surface plasmons, the sensor, including a thin gold or silver layer coted on an optical glass substrate, may be placed on surface of a prism. To increase efficiency of sensor detection, a transparent optical oil may be used at prism-substrate interface. In this paper, the effect of oil layer at prism–substrate interface on the sensor response is studied theoretically. The results show that although the sensor efficiency isn’t affected by oil layer in the air medium, it is lost by an oil layer more than 100 of nm in water medium.