For the astronomer, x-ray interferometry is the theory and practice of building dilute aperture telescopes for studying celestial x-ray sources. The short wavelengths and high surface brightness of x-ray sources will make the eventual scientific payoff very high, with direct imaging of the event horizons of black holes as the centerpiece. In this article we review the history of x-ray interfero...

Digitally enhanced heterodyne interferometry is a laser metrology technique employing pseudo-random codes phase modulated onto an optical carrier. We present the first characterization of the technique's displacement sensitivity. The displacement of an optical cavity was measured using digitally enhanced heterodyne interferometry and compared to a simultaneous readout based on conventional Poun...

We retrieve reflected plane waves by applying seismic interferometry to the recorded ground motion from a cluster of earthquakes. We employ upgoing/downgoing P/S wavefield decomposition, time windows, time reversal, and multi-dimensional deconvolution (MDD) to improve the quality of the extraction of reflected waves with seismic interferometry. Because MDD interferometry requires the separation...