Spatially Addressable Readout and Erasure of an Image in a Gradient Echo Memory

TL;DR

This paper demonstrates spatially selective readout and erasure of images stored in a gradient echo memory using a warm rubidium vapor, advancing quantum signal processing capabilities.

Contribution

It introduces a method for targeted retrieval and erasure of image portions in a quantum memory using local optical addressing and scattering techniques.

Findings

Spatially addressable readout achieved with a control beam.

Optical erasure induces decoherence, enabling image erasure.

Atomic diffusion limits the memory's spatial capacity.

Abstract

We show that portions of an image written into a gradient echo memory can be individually retrieved or erased on demand, an important step towards processing a spatially multiplexed quantum signal. Targeted retrieval is achieved by locally addressing the transverse plane of the storage medium, a warm 85Rb vapor, with a far-detuned control beam. Spatially addressable erasure is similarly implemented by imaging a bright beam tuned near the 85Rb D1 line in order to scatter photons and induce decoherence. Under our experimental conditions atomic diffusion is shown to impose an upper bound on the effective spatial capacity of the memory. The decoherence induced by the optical eraser is characterized and modeled as the response of a two level atom in the presence of a strong driving field.