Fabrication and enhancement of sensor for measuring NaCl concentrations using surface plasmon resonance

초록

In this research, we fabricate a SPR sensor which can classify each density of NaCl solution. This sensor chip is composed of 3-layer, Sample/Gold film/Prism, as Kretschmann configuration[3]. Fig.1 shows a schematic diagram of the fabricated SPR sensor. A 650-nm Laser diode(Laser Lab Inc.) was TM-polarized and collimated with a lens through the prism onto the Au film substrate. The Au film substrate is realized sputtered Cr(5nm) and Au(45nm) on Fused Silica(FS) substrate with 1mm-thickness. And it is attached to a FS right angle prism(CVI Inc.) using index matching oil(Cargille Laboratories Inc.)[4]. The incident(TM-polarized) light came in contact with the solution on the Au surface, and the reflected light was detected by a photodiode detector. The reflectance was measured using a 2-channel optical power meter(Newport Inc.). Both the prism and Au film substrate were mounted on a motorized rotating stage(Suruga Seiki Inc.) to control the angle of incident light. The data is collected by a computer connected to the experimental apparatus using a homemade Labview program.