Dynamic response of a Fabry–Perot interferometer

We predict and measure the temporal response of a Fabry–Perot cavity field to changes in cavity length and frequency of the incident laser field. We outline the theoretical differences between changes in the cavity-length and laser-frequency modulation and present a theoretical derivation of the time response of the resulting cavity field and its effect on the reflected field, the transmitted field, and the Pound–Drever–Hall error signal. We show that oscillations in the resulting signals are due to oscillations in the amplitude and the phase of the cavity field itself. Finally, we demonstrate how induced cavity-field oscillations may be used to determine the mirror velocity or the frequency change of the injected laser field.