Evanescent waves enhancement

The absorption-based platforms described previously employed evanescent wave interrogation of a thin sensing layer coated onto a planar waveguide. A sensitivity enhancement strategy for optical absorption-based sensors based on planar, multimode waveguides was developed recently by us18. The objective was to apply this theory to the development of low-cost, robust and potentially mass-producible sensor platforms and the following section outlines the assumptions and predictions of this theoretical model. 

Krioukov E., Klunder D.J.W., Driessen A., Greve J., Otto C., Integrated optical microcavities for enhanced evanescent-wave spectroscopy, Optics Letters 2002 27 1504-1506. 

The cavity-enhanced evanescent-wave sensing method described in Sect. 5.2 and applied to gases in Sect. 5.3 can also be employed for the detection of chemicals in liquid solution. In addition, the intracavity enhancement provided by the high-g... 

The enhancement techniques briefly described in this section are just a few of those that can be used to make cavity-enhanced evanescent-wave chemical detection even more sensitive. The use of dielectric microresonators with tapered-fiber coupling enables performance that is difficult to achieve in other configurations, while minimizing the sensor size. 

In conclusion, when a WGM is excited in a dielectric microresonator, its evanescent component provides a convenient probe of the microresonator s surroundings. Various ways to implement evanescent-wave sensing have been devised, but the emphasis of this chapter has been on microcavity-enhanced absorption spectroscopy. The techniques described here have broad applicability, can even be used with broadband sources, and lend themselves well to further enhancement methods. We are looking forward to continuing our development of these sensors. 

Farca, G., Cavity Enhanced Evanescent Wave Chemical Sensing Using Microresonators, PhD dissertation, Oklahoma State University, 2006... 

Blair, S. Chen, Y., Resonant enhanced evanescent wave fluorescence biosensing with cylin drical optical cavities, Appl. Opt. 2001, 40, 570 582... 

Krioukov, E. Klunder, D. J. W. Driessen, A. Greve, J. Otto, C., Integrated optical micro cavities for enhanced evanescent wave spectroscopy, Opt. Lett. 2002, 27, 1504 1506... 

B.D. MacCraith, Enhanced evanescent wave sensors based on sol-gel-derived porous glass coatings, Sensor Actuat. B-Chem., 11(1-3) (1993) 29-34. 

The utihzation of fluorescence dyes for analytical measurements enhances the sensitivity for the detection of the molecules of interest. First, Cronick and Little made use of evanescent wave excitation for a fluorescence immunoassay, in 1975. By using totally internally reflected light, they excited the fluorescence of a fluorescein-labeled antibody which has become bound to a hapten-protein conjugate adsorbed on a quartz-plate in an antibody solution [41]. Contrary to the label-free high-refractive-index sensors where the mass of the molecule of interest is... 

Lezec HJ, Thio T (2004) Diffracted evanescent wave model for enhanced and suppressed optical transmission through subwavelength hole arrays. Opt Express 12 3629-3651 Flammer PD, Schick IC, Collins RT, Hollingsworth RE (2007) Interference and resonant cavity effects explain enhanced transmission through subwavelength apertures in thin metal films. Opt Express 15 7984-7993... 

Kaiser, R., Levy, Y., Vansteenkiste, N., Aspect, A., Seifert, W., Leipold, D., and Mlynek, J. (1994). Resonant enhancement of evanescent waves with a thin dielectric waveguide. Optics Comm. 104 234-240. 

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