Scientists discovered a new platform for quantum technologies by suspending two-dimensional (2D) crystals over pores in a slab of gold. When heated, the metal reflows to form a porous structure and the gold atoms lock into registry with the atoms in the 2D layer on top. Instead of droplets forming on the glass base underneath the gold, heating caused a reorientation of the underlying metal slab. The gold became porous throughout and this physical change led researchers to test for other side effects of the merger.

Suspended 2D crystals over pores in a slab of gold (center image) allow scientists to connect quantum light sources (inset images) in a ready-made network. (Image: Jeremy Robinson/U.S. Naval Research Laboratory)

They also discovered that the combination can create a large number of quantum light sources in a ready-made network. The alignment between atomic layers may facilitate energy transfer between the emitters through the gold framework that connects them.

Researchers verified that light emanating from the 2D semiconductors comes out as single light particles, or photons. These emitters can transfer energy to each other through the gold layer. The light shines on one part of the sample and researchers look at the light coming off at another part. This shows how energy can be coupled into the gold layer at one point, propagated to a different quantum emitter site far away, and re-emitted as visible light.

The ability to remotely control the piping of energy to a single-photon emitter makes this an attractive system for quantum technology. Sensors are a first application; they can take advantage of the atomically thin membranes stretched across the porous metal framework.

While researchers conducted this work using a gold slab underneath the thin semiconductor layer, other metals can respond the same way as the gold. The team continues to investigate how various material combinations and structures can create single photon sources with unique properties, a key component of secure communications.

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