EOT-based chemical and biological sensing (for example, improving ELISA based antibody detection) is another major area of research. Much like in a traditional surface plasmon resonance sensor, the EOT efficiency varies with the wavelength of the incident light, and the value of the in-plane wavevector component. This can be exploited as a means of transducing chemical binding events by measuring a change in the local dielectric constant (due to binding of the target species) as a shift in the spectral location and/or intensity of the EOT peak. Variation of the hole geometry alters the spectral location of the EOT peak such that the chemical binding events can be optically detected at a desired wavelength. EOT-based sensing offers one key advantage over a Kretschmann-style SPR chemical sensor, that of being an inherently nanometer-micrometer scale device; it is therefore particularly amenable to miniaturization.