Experimental Validations of Divergent Beam Illumination and Detection Conditions in a Surface Plasmon Resonance Sensor Using a Powell Lens
J. Widjaja and J. H. Hossea
Divergent beam illumination and detection conditions in surface plasmon resonance (SPR) sensors using a Powell lens is experimentally verified by sensing air, water and ethanol. The experimental results are in good agreement with the analytical conditions even for a large range of refractive index measurements. It is also found that the sensor system has high sensitivity and accuracy of measurements and a linear response. Owing to the uniform energy distribution of the divergent beam generated by the Powell lens, surface plasmons can be efficiently resonated across a broad sensing area, yielding simplification of SPR dip detection algorithm. It is, therefore, suitable for implementation of multichannel SPR sensors.
Keywords: He-Ne laser, Powell lens, surface plasmon resonance (SPR) sensor, divergent beam illumination, resonance angle, fan angle, illumination angle, detection angle, geometrical optics