An integrated optical capillary electrophoresis system for analyzing an analyte.
A modulated optical pump beam impinges on an capillary containing the analyte/buffer
solution which is separated by electrophoresis. The thermally-induced change in
the index of refraction of light in said electrophoresis capillary is monitored
using an integrated micro-interferometer. The interferometer includes a first interferometer
arm intersecting the electrophoresis capillary proximate the excitation beam and
a second, reference interferometer arm. Changes in index of refraction in the analyte
measured by interrogating the interferometer state using white light interferometry
and a phase-generated carrier demodulation technique. Background thermo-optical
activity in the buffer solution is cancelled by splitting the pump beam and exciting
pure buffer solution in a second section of capillary where it crosses the reference
arm of the interferometer.
