Grating coupler sensor

In grating coupler sensors, a diffraction grating is used to couple light in (Figure 12) or out of (Figure 13) a waveguide18. In the input grating coupler... 

Table 2. Responses of a grating coupler sensor coated with multilayers of monoclonal antibodies to the respective analytes. The response values are related to that of an adsorbed antibody monolayer (B2M p2-microglobulin, HCG human choriogonadotropin, HRP horseradish peroxidase.

Table 1 Different detection limits of grating coupler sensors...

Clerc D., Lukosz W., Integrated optical output grating coupler as biochemical sensor, Sensors and Actuators B 1994 19 581-586. 

Nellen, Ph. Tiefenthaler, K. Lukosz, W., Integrated optical input grating couplers as bio chemical sensors, Sens. Actuators 1988, 15, 285 295... 

D. Clerc and W. Lukosz, "Integrated Optical Output Grating Coupler as Biochemical Sensor," Sensors and Actuators B19, 581-586 (1994). 

Fig. 10 Different refractive-index-based sensors, a A grating coupler, where Ns, Nw and Nm are the refractive indexes of the substrate, the waveguide and the surrounding medium respectively, b A resonant mirror, where Nm, Nr and Nc are the refractive indexes of the medium, the resonant layer and the coupling layer...

For refractive-index-type sensors, the waveguide is intrinsically the sensing element, and then chemical processes are measured with the variations of the refractive index, n, of guided modes. The majority of the various sensor types and published configurations make use of grating couplers (Fig. 10a) [83,84], resonant mirrors (Fig. 10b) [52,86-89] or interferometric sensors (Fig. 11) as... 

The biosensing devices focus mainly on affinity principles such as antibody -antigen reactions and are based on surface plasmon resonance [25], grating couplers[26] or interferometers [27]. It seems possible to get stable and highly sensitive devices based on these principles [28], and further investigations can lead to miniaturized sensor modules with reduced cost, size and complexity. 

A chemical sensor is a device that transforms chemical information into an analytically useful signal. Chemical sensors contain two basic functional units a receptor part and a transducer part. The receptor part is usually a sensitive layer, therefore a well founded knowledge about the mechanism of interaction of the analytes of interest and the selected sensitive layer has to be achieved. Various optical methods have been exploited in chemical sensors to transform the spectral information into useful signals which can be interpreted as chemical information about the analytes [1]. These are either reflectometric or refractometric methods. Optical sensors based on reflectometry are reflectometric interference spectroscopy (RIfS) [2] and ellipsometry [3,4], Evanescent field techniques, which are sensitive to changes in the refractive index, open a wide variety of optical detection principles [5] such as surface plasmon resonance spectroscopy (SPR) [6—8], Mach-Zehnder interferometer [9], Young interferometer [10], grating coupler [11] or resonant mirror [12] devices. All these optical... 

Tiefenthaler K, Lukosz W (1989) Sensitivity of grating couplers as integrated-optical chemical sensors. J Opt Soc Am B 6 209-220... 

Nellen PM, Lukosz W (1990) Integrated optical input grating couplers as chemo- and immunosensors. Sensors Actuators B Chem 1 592-596... 

Lukosz W, Nellen PM, Stamm C, Weiss P (1990) Output grating couplers on planar waveguides as integrated optical chemical sensors. Sensors Actuators B Chem 1 585-588... 

Brandenburg A, Gombert A (1993) Grating couplers as chemical sensors a new optical configuration. Sensors Actuators B Chem 17 35 0... 

Tiefenthaier K, Lukosz W (1985) Grating couplers as integrated optical humidity and gas sensors. Thin Solid Films 126 205-211... 

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