Abstract
We describe a highly sensitive sensor which uses the evanescent field of a reusable planar optical waveguide as the sensing element. The waveguide used is optimized to obtain a steep dependence of the propagation velocity on the refractive-index profile near the surface. The adsorption of a layer of proteins thus results in a phase change, which is measured interferometrically using a Mach-Zehnder interferometer set-up. The stability of the interferometer is such that phase changes = (1 × 10-2)2pi per hour can be measured. Immunoreactions have been monitored down to concentrations of 5 × 10-11 M of a 40 kDa protein.
Original language | English |
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Pages (from-to) | 209-217 |
Number of pages | 9 |
Journal | Sensors and Actuators B: Chemical |
Volume | 10 |
Issue number | 3 |
DOIs | |
Publication status | Published - 1993 |