Page 307 - Organic Electronics in Sensors and Biotechnology

284 Chapter Seven

4. Resonant methods
A very promising principle for an integrated optical sensor is
the utilization of resonant effects in a photonic cavity coupled
to a waveguide. A chemical modification of the cavity by an
infiltrated analyte or a binding molecule results in a shift of the
resonant frequency ω → ω . This shift can then be detected.
0 1
See Fig. 7.18.
The photonic cavity can be of various types. The quality
factor which determines the width of the resonance peak

ω 0 ω 1

ω 0 ω 1

FIGURE 7.18 Scheme of the resonant detection method.