Spectral interferometry-based surface plasmon resonance sensor

Spectropolarimetric Surface Plasmon Resonance Sensor and the Selection of the Best Polarimetric Function

“…Assuming the accuracy level of the analyzer rotation stage is 3 10  degrees, and the noise in the intensity is 10 counts, we get a LOD of 6 10 4 . 2   RIU, which is comparable to the best newly reported works based on the spectral interrogation such as [24,31] and [37]. With more sophisticated systems this figure can be lowered by two orders of magnitudes.…”

“…They relate to the reflectance ratio TE TM R R / as the polarimetric parameter, while this is not accurate because this represents  2 tan without any relation to the phase difference. So, even in our case, which is far away from optimal, we achieved higher detection accuracy than theirs [31].…”

“…2    nm for the phase difference derivative, but here we managed to achieve better detection accuracy of  nm for a 62nm silver thickness (which is not the optimal thickness) with water as the analyte. It seems that the definition that was given to the polarimetric method in that work [31] is not correct. They relate to the reflectance ratio TE TM R R / as the polarimetric parameter, while this is not accurate because this represents  2 tan without any relation to the phase difference.…”

“…A recent work based on spectral interferometry [31] claimed that the detection accuracy of the interferometric measurements is three times higher than that of the polarimetric measurements. They reported a detection accuracy of 1 2 10 9 .…”

“…Phase sensitive SPR sensors show a lower LOD [12][13][14] than other SPR sensors. However, phase measurement setups are in general more complicated compared to the intensity measurement setups [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31], require more stability and are very sensitive to external vibrations and noise. These measurement setups include heterodyne interferometry [15,16], phase quadrature interferometry [17], Mach-Zehnder interferometer [18][19][20], Fabry-Perot interferometer [21][22][23], Michelson interferometer [24,25], interferometry based on a liquid crystal variable wave plate and an inverted white light optical microscope [26] and configurations with an electro-optic modulator [27] or a photoelastic phase modulator [28].…”