Superresolution imaging with entanglement-enhanced telescopy

Abstract

Long-baseline interferometry will be possible using pre-shared entanglement between two telescope sites to mimic the standard phase-scanning interferometer, but without physical beam combination. We show that spatial-mode sorting at each telescope, along with pre-shared entanglement, can be used to realize the most general multimode interferometry on light collected by any number of telescopes, enabling achieving quantitative-imaging performance at the ultimate limit pursuant to the baseline as afforded by quantum theory. We work out an explicit example involving two telescopes imaging two point sources.

Figures (2)

• Figure 1: (a) A two-telescope array of baseline $b$ points toward two weakly emitting stars of angular separation $2\theta$. A star photon arriving at site A is shown. (b) The incoming photon is fed into a spatial mode demultiplexer (SPADE). An excitation is shown to occur in the second mode basis and in the fifth time bin of a block of integration time in which roughly one photon arrives. (c) The photonic state is loaded into the memory qubits via photon-memory CNOT gates, a compressive binary encoding, and performing X-basis measurements on the photon. (d) Entangled pairs pre-distributed among the telescope sites assist in performing a sequence of operations that reveal the arrival time and spatial mode index, which combined with (e) The X measurement results of relevant memory atoms, resuls in a single-bit post-processed outcome whose empirical probability over measurements of many time blocks containing one photon each, is the sufficient statistic to estimate $\theta$ at the QFI-mandated precision limit.
• Figure 2: CFI normalized to the QFI, plotted as a color chart, versus separation $\theta/\sigma$ and baseline to aperture-diameter ratio $r$. Four values of the spatial-mode cuffoff $K$ are shown, with the top right corresponding to a binary SPADE ($K=2$) attaining the QFI in the sub-Rayleigh regime ($\theta/\sigma < 1$).