| 摘要 |
<p>Apparatus for measuring a phase shift induced in a light signal has a first light source for emitting a light signal along a measurement optical path that includes a sample, for example a fluorescent sample, and a second light source for emitting a light signal along a dummy measurement optical path. A measurement electronic circuit is provided for receiving the light signals and providing outputs separated in time which are indicative of the phase of the respective light signals. In use, a phase shift is induced in light in the measurement optical path by the fluorescent sample. A reference electronic circuit is provided for receiving a signal indicative of the phase of the light signals emitted by the first and second light sources. Circuitry is provided to compare the respective phases of light output from the two circuits to provide an output indicative of a first measured phase difference during operation of the first light source. A correction is then applied to this measurement by taking a similar phase difference measurement during operation of the second light source and comparing the two phase differences.</p> |
