The application of capacitance micrometry to the control of Fabry-Perot etalons

Abstract

Using the technique of capacitance micrometry it is possible to measure very small displacements. The authors describe the application of this technique to the control of piezo-scanned Fabry-Perot etalons using a closed-loop feedback system. This system removes the problem of the nonlinear response and hysteresis associated with piezoelectric transducers and allows precise control of both etalon gap and parallelism.