The prospects for optical quantum networks—in which information is transmitted by encoding data using the quantum state of photons—has been on the upswing lately, leading to some commercial quantum photonics products currently on the market.
However, optical quantum memory, which is one of the key technologies for the realization of widespread, optical, quantum networks, remains a sticking point. Optical quantum memory is a device that takes a photon and encodes it with information. Unfortunately, the devices developed to date have been too large and inefficient to operate in a chip-scale quantum device.
Now an international team of researchers led by a group from the California Institute of Technology (Caltech) has managed to create an optical quantum memory device that is over 1000 times smaller than anything previously available. Not only is the device significantly smaller than anything that has come before it—ensuring will fit into on-chip devices—it is capable of on-demand retrieval of the stored data.
In research described in the journal Science, researchers from Caltech, the National Institute of Standards and Technology (NIST), and the University of Verona, Italy have collaborated on the development of a nano-sized cavity containing neodymium. That cavity in turn creates a crystal cavity that enhances the interaction between light and the cavity’s neodymium at the single photon level.