Optical phase shift measurement
Figure 1 Schematic diagram of the system
|
An optical phase shift measurement system based on a Michelson interferometer and a linear photo detector was developed. The schematic diagram of the system is shown in Figure 1.
The signal of the equidistant fringe detected by the linear photo detector was sent to an oscilloscope and averaged, thereafter the signal was acquired and processed by a computer for extracting the phase information. A so called trough integration method was used in the data processing. The efficacy of this method in the improvement of measurement precision is confirmed both theoretically and experimentally. |
Figure 2 The displacement versus the driving voltage of a piezo crystal actuated mirror.
|
The measurement precision of the system was tested by measuring the phase shift of a piezo crystal actuated mirror. And the measurement result shows that a 0.12-nm standard deviation was achieved in the displacement measurement as shown in Figure 2.
|
More detail about this work can be found here.