Interferometric sensor for detection of surface-bound bioreactions.
An integrated optical interferometer for direct detection of affinity reactions is presented. A modern version of a Young's interferometer is built with a waveguide structure as beam splitter and as sensing element. Resistive waveguides were produced by plasma-enhanced chemical vapor deposition of silicon oxinitride. At the output of this device a fringe pattern is detected by a CCD line camera. The adsorption of molecules on top of the waveguides is observed with a detection limit of 750 fg/mm(2). The resolvable variation of effective refractive index is 9 x 10(-8).
Brandenburg
A
A
Fraunhofer-Institute of Physical Measurement Techniques, Heidenhohstrasse 8, Freiburg D-79110, Germany. albrecht.brandenburg@ipm.fhg.de
Krauter
R
R
Künzel
C
C
Stefan
M
M
Schulte
H
H