Numerical method for high accuracy index of refraction estimation for spectro-angular surface plasmon resonance systems

Abstract

An eigenvector analysis based algorithm is presented for estimating refractive index changes from 2-D reflectance/dispersion images obtained with spectro-angular surface plasmon resonance systems. High resolution over a large dynamic range can be achieved simultaneously. The method performs well in simulations with noisy data maintaining an error of less than 10(-8) refractive index units with up to six bits of noise on 16 bit quantized image data. Experimental measurements show that the method results in a much higher signal to noise ratio than the standard 1-D weighted centroid dip finding algorithm.

Design and analysis of a spectro-angular surface plasmon resonance biosensor operating in the visible spectrum

“…It has previously been shown that this method depends greatly on both the resolution of the camera and even more significantly on the bit depth of the data acquisition. 11 A spectro-angular SPR system built in our laboratories with a light source at 850 nm and the detection limit of the system, 1.5 × 10 −6 RIU, was found to be close to the predicted detection limit for the camera resolution and bit depth. 10 In order to improve the detection limit of the SPR biosensor, we sought to employ image sensors with greater bit depth and more pixels.…”

“…The details of the DPM method are described in Alleyne et al 11 Briefly, this method employs a set of tion is performed; the matrix of reflection images is projected on the SVD processed matrix to obtain the basis set. With the basis set in memory, every image of unknown refractive index is rearranged into a column vector and is projected against the SVD processed matrix creating a weight vector.…”

“…The analysis method developed for the spectro-angular SPR biosensor is referred to as the double projection method (DPM). 11 This method consists in creating a basis set of SPR images through single-value decomposition and evaluating each new image using this basis to extract the refractive index of the sample. It has previously been shown that this method depends greatly on both the resolution of the camera and even more significantly on the bit depth of the data acquisition.…”

Phase‐sensitive surface plasmon resonance biosensors: methodology, instrumentation and applications

“…Despite the involvement of more complicated experimental arrangements for simultaneous collecting of angularspectral data, such approach demonstrated an improvement in resolution of imaging schemes [38]. In addition, angular-spectral interrogation renders possible the application of novel advanced algorithms for the treatment of signals, yielding potentially to a much lower detection limit for refractive index estimation [39].…”

Dimensions and refractive index estimates of deeply buried optical waveguides in Lithium Fluoride

“…The increase ( ) in the spatial RI profile and the waveguide core dimensions can be estimated by different techniques, such as reflectivity method [2], scattering pattern [3], surface plasmon resonance [4], prism coupling [5,6], surface topography [7], refraction method and estimate from near field profile (NFP) [8,9]. An inversion of the scalar wave equation to estimate the dimensions and the RI profile of the waveguide is possible with good signal noise ratio NFP [10].…”