Analysis of the Sensitivity of Self-focused Nonlinear Optical Evanescent Waveguide Sensors

Abstract

This article presents an extensive theoretical analysis of nonlinear sensors consisting of a thin dielectric film surrounded by a self-focusing nonlinear cladding and a linear substrate. The sensitivity in evanescent optical waveguide sensors is derived when the effective index is greater and smaller than the refractive index of the guiding layer. The behavior of the sensitivity with different parameters of the structure is presented. Closed form analytical expressions and normalized charts are given to provide the conditions for the maximum sensitivity of nonlinear sensors when the measurand is homogeneously distributed in the semi-infinite waveguide cover (homogeneous sensing). The results will be compared with those of the well known linear evanescent waveguide sensors.

Lossy double negative guiding layer optical sensors

“…(6). In our analysis, the free space wavelength l is con− sidered to have the value of 1550 nm, and the fundamental mode for which the mode order is zero is considered since it has the highest sensitivity [19]. Figure 3 shows the real part of the sensitivity of the pro− posed sensor vs. the real part of the guiding layer per− mittivity at t = 100 nm and μm = -μ o (m = -1).…”

“…Therefore the sensitivity S of the opti− cal waveguide sensor is defined as the rate of change of the effective refractive index under an index change of the cover ( ) S N n c = ¶ ¶ [19]. Differentiating the characteristic equation given by Eq.…”

Symmetrical Five - Layer Slab Waveguide Sensors including Two Identical Left Handed Materials as Mid-Layers = مجسات المرشدات الموجية المتماثلة ذات خمس طبقات تحتوي على طبقتين وسطيتين متماثلتين من المواد اليسارية

“…Many theoretical studies concerning analysis of dispersion equations were introduced for many planar waveguide structures comprising linear and nonlinear media (Ankiewicz andTran 1991, Fontaine 1991). The slab (planar) optical waveguides have been intensively studied in optical sensors (Shabat et al 2007, Tiefenthaler 1998and Shi et al 2016 in which the effective refractive index is used to probe the variations in the refractive index of an analyte. Sensing is performed by the evanescent tail of the field in the cover medium (Veldhuis et al 2000, Kunz 1997.…”

Nonlinear planar asymmetrical optical waveguides for sensing applications

“…The reverse symmetry waveguide has been tested for bacterial and cell detection and it showed a considerably high sensitivity compared with the conventional waveguide sensor. We have investigated the sensitivity of nonlinear waveguide structure where one of the layers of the waveguide structure is considered to be nonlinear medium [13,14].…”