Control and tuning of a suspended Fabry-Perot cavity using digitally-enhanced heterodyne interferometry

摘要

We present the first demonstration of real-time closed-loop control anddeterministic tuning of an independently suspended Fabry-Perot optical cavityusing digitally-enhanced heterodyne interferometry, realising a peaksensitivity of $\sim$10 pm$/\sqrt{\mathrm{Hz}}$ over the 10-1000 Hz frequencyband. The methods presented are readily extensible to multiple coupledcavities. As such, we anticipate that refinements of this technique may findapplication in future interferometric gravitational-wave detectors.