Zhang, YaBandutunga, ChathuraGray, Malcolm BChow, Jong2020-06-192020-06-191094-4087http://hdl.handle.net/1885/205384We present a free-space, continuous-wave laser interferometric system capable of multi-target dynamic phase measurement at acoustic frequencies up to a Nyquist bandwidth of 10.2 kHz. The system uses Digitally-enhanced Heterodyne Interferometry to range gate acoustic signals simultaneously from multiple in-line reflections while isolating coherent cross-talk between them. We demonstrate sub-nanometer displacement sensitivity across the audio band for each individual reflection surface and 1.2 m resolution between successive surfaces. Signals outside the 1.2 m range-gate of the system were suppressed by greater than 30 dB in amplitude, enabling high fidelity independent acoustic measurements.Australian Government Research Training Program (RTP) Scholarshipapplication/pdfen-AU© 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement201910.1364/OE.27.0184772020-01-19