Differential ellipsometric surface plasmon resonance sensors with liquid crystal polarization modulators
Hooper, Ian R.
Sambles, J. Roy
University of Exeter
Applied Physics Letters
American Institute of Physics
Differential ellipsometric interrogation of surface plasmon (SP) resonances is a technique that gives ultrahigh sensitivity to refractive index changes, and it may provide the basis for chemical and biological sensors. In this study, a liquid crystal polarization modulator has been developed to provide such a differential technique. A refractive index sensitivity of 2×10–7 refractive index units is demonstrated, which is at least as sensitive as more established SP sensing techniques. The use of a liquid crystal modulator allows for low-voltage signal modulation and also feedback locking to zero. Possibly more important, it leads to pixelization for array sensing and for potential imaging.
Copyright © 2004 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Applied Physics Letters 85 (2004) and may be found at http://link.aip.org/link/?APPLAB/85/3017/1
85 (15), pp. 3017-3019