A study on refractive index sensors based on optical micro-ring resonators

Abstract

Abstract:In this work, the behavior of refractive index sensors based on optical micro-ring resonators is studied in detail. Using a result of waveguide perturbation theory in combination with numerical simulations, the optimum design parameters of the system, maximizing the sensitivity of the sensor, are determined. It is found that, when optimally designed, the sensor can detect relative refractive index changes of the order of n/n310 4 , assuming that the experimental setup can detect relative wavelength shifts of the order of /310 5. The behavior of the system as bio-sensor has also been examined. It is found that, when optimally designed, the system can detect refractive index changes of the order of n10 3 for a layer thickness of t=10 nm, and changes in the layer thickness of the order of t0.24 nm, for a refractive index change of n=0.05.

A semi-empirical integrated microring cavity approach for 2D material optical index identification at 1.55 μm

“…!" , here, for our case, since the resonance shift occurs over a narrow wavelength range, where dneff/dλ <<1, considering first order dispersion term, we approximate ng as neff [30,31]. Therefore, the change in effective mode index (∆ !""…”

Critical-Angle Differential Refractometry of Lossy Media: A Theoretical Study and Practical Design Issues

“…Other quantities are dimensionless. Sensor's linear range can be deduced from available data by use of Equation (16). Minimum useful signal (i.e., relative intensity change) at the detector amounts to S · DL ≈ 4%, 2% and 0.4%, for Cases 1, 2 and 3, respectively.…”

“…Refractive index sensors are intensely investigated for numerous biomedical [1][2][3], chemical [4,5] and industrial [6,7] applications. An indicative yet far from exhaustive list of sensing mechanisms relies on plasmonic [8][9][10][11], photonic crystal [12][13][14][15], micro-cavity [16][17][18][19], optical fiber [20][21][22][23] and wave-guide [24][25][26][27] configurations. Associated with Fresnel reflectance properties at planar interfaces, differential refractometry offers an alternative path to sensing refractive index changes, by exploitation of interference [28], deflection [29] or (more relevant to the present work) critical-angle [30][31][32][33][34][35] effects.…”

Vertical silicon nanowire-based racetrack resonator optical sensor

“…In this section we investigate the capability of our silicon nanowire sensor to function as a biosensor with thin biolayers attached on the surface of the SiNWs. We simulate the biosensing situation where a thin biomaterial layer of only 10 nm thickness [26] gets attached to the surface of the SiNWs of our proposed sensor. The refractive index of such biolayer was varied from 1.35 to 1.60 to account for a number of biomaterials in that index range such as the n = 1.47 bovine serum albumin [27] and the n = 1.5 biotin-streptavidin [28].…”