Figure 2
From: Diffractive Optical Analysis for Refractive Index Sensing using Transparent Phase Gratings
NaCl-DI water mixtures with varying salt content were introduced inside the sample cell at instances indicated by the black arrows.
Drift compensation by ratioing the zeroth and first order diffraction intensities is apparent (0.3 M step in (a)) in R-mode as well as in the T-mode (2 M step in(b)). The response of the sensor in this range was roughly linear as shown in (c) for both R (main figure) and T-mode (inset) measurements. The limit of detection (LoD) was estimated for R-mode measurements using NaCl-DI water mixtures of lower concentration (d). The noise-equivalent LoD was found to be around 6 × 10−7 RIU.
