New Hebrew University research has made a major breakthrough by successfully implementing single-photon sources into small chips that operate at room temperature. This development marks a crucial advance in the field of quantum photonics, opening up possibilities for its use in quantum computing and cryptography. This is a key advance in the creation of usable quantum photonic devices, signaling an optimistic outlook for the full realization of quantum technologies, including computing, communication and sensing.
A recent study led by Boaz Lubocki during his Ph.D. Research with Professor Ronen Rapaport from the Cancer Physics Institute at the Hebrew University of Jerusalem in collaboration with teams from Los Alamos National Laboratory (LANL) in the US and the University of Ulm in Germany has revealed significant progress towards — single-photon source integration chip at room temperature. This achievement is a significant step forward in the field of quantum photonics and holds promise for various applications including quantum computing, cryptography and sensing.
Innovations in antenna design
The key innovation is the introduction of a hybrid metal-dielectric apple antenna, which provides exceptional photon directivity. This new antenna design provides efficient back-excitation of photons by placing the emitter in a subwavelength hole located in the center of the antenna. This configuration provides both direct back-excitation and highly efficient forward coupling of radiation to low numerical aperture optics or optical fibers.
The study demonstrates the versatility of this concept by fabricating devices containing either colloidal quantum dots or nanodiamonds containing silicon vacancy centers, both of which are excellent single photon emitters even at room temperature. These emitters were precisely positioned using two different nanopositioning techniques.
Notably, both types of reverse-excitation devices showed a forward collection efficiency of about 70% at numerical apertures as low as 0.5. This means that it is possible to use very simple and compact optical elements and still collect most of the photons into the desired channel or accurately send the emitted photons to the adjacent optical fiber without the need for any additional communication optics. This is a key ingredient in the integration of quantum light sources into real quantum systems. This simplified process promises to simplify future integration efforts and accelerate the realization of practical quantum photonic devices.
Boaz Lubocki commented on the importance of this achievement, stating: "By overcoming the key challenges associated with the integration of single-photon sources on a crystal, we have opened up exciting new opportunities for the development of advanced quantum technologies.
The successful integration of single-photon sources into tiny microcircuits at room temperature, achieved through the innovative use of a hybrid metal-dielectric “apple” antenna, has direct applications in the improvement of quantum cryptography for secure communication, improvements in sensing technologies and optimization of the integration process for practical quantum photonic devices. The research results open the door to commercial applications and the development of new products in the emerging field of quantum technology.