Researchers at Purdue University have trapped alkali atoms (cesium) on an integrated photonic circuit, which behaves like a transistor for photons. This discovery has the potential to build a quantum network based on cold-atom integrated nanophotonic circuits.
The team used lasers to cool and tightly trap the atoms on the integrated circuit, where light propagates in a small photonic “wire.” The atoms were “frozen” at negative 459.67 degrees Fahrenheit, or just above absolute zero temperature, and are essentially standing still.
A key aspect of this research is that this atom-coupled microring resonator serves as a “transistor” for photons. The trapped atoms can be used to gate the flow of light through the circuit. If the atoms are in the correct state, photons can transmit through the circuit. Photons are entirely blocked if the atoms are in another state.
The team has successfully trapped up to 70 atoms that could collectively couple to photons and gate their transmission on an integrated photonic chip. This has not been realized before.
This platform demonstrated in this research could provide a photonic link for future distributed quantum computing based on neutral atoms, or serve as a new experimental platform for studying collective light-matter interactions and for synthesizing quantum degenerate trapped gases or ultracold molecules.
Source: https://phys.org/news/2024-07-atoms-photonic-transistors.html