Science Advances posts photon-extraction study

Science Advances highlighted a new paper on May 24 that tackles a basic bottleneck in quantum hardware: getting useful photons out of solid materials in the first place. (x.com) The study, published in *Science Advances* as “Probing individual quantum emitters in bulk semiconductors via photonic nanojets,” comes from Behrooz Semnani, Sai Sreesh Venuturumilli, Mohammad Soltani, Pratik Adhikary, Abdolreza Pasharavesh, Nikolay Videnov, Paul Anderson, Supratik Sarkar, Vinodh Raj Rajagopal Muthu and Michal Bajcsy. It was published on May 20, 2026, according to the journal record. (science.org) At the center of the paper is a familiar problem in quantum photonics. Solid-state quantum emitters — defects embedded inside materials such as diamond — can act as single-photon sources and spin qubits, but the host materials’ high refractive index makes the emitted light hard to collect efficiently. The paper says that low photon-collection efficiency and the difficulty of isolating individual emitters have both limited practical use. (science.org) The authors’ approach is to pattern monolithic nanostructures directly into the bulk material. Using free-form topology optimization, they designed structures that create tightly confined “photonic nanojets,” meaning highly localized beams that can selectively excite individual emitters while also improving how many photons escape into the measurement system. (science.org) In their demonstration platform, the team used negatively charged nitrogen-vacancy, or NV−, centers in a low-cost diamond sample at room temperature. The paper reports a 10-fold power enhancement for selective single-emitter excitation and more than a 15-fold improvement in photon-extraction efficiency for photoluminescence collection in confocal microscopy. (science.org) That matters because the work is aimed at bulk materials rather than only carefully isolated emitters in highly engineered nanophotonic devices. The paper says the method works in a relatively dense ensemble of randomly distributed quantum emitters, and the optimized geometries also suppress background photoluminescence from near-surface defects and other emitters in the bulk, improving signal-to-noise. (science.org) A University of Waterloo research summary described the device as a diamond structure that “funnels and aims” a highly localized beam of photons at single engineered defects while being optimized to extract photons. The same summary said the group used an automated inverse-design approach to shape a two-dimensional structure on the diamond surface. (uwaterloo.ca) The broader claim in the paper is that the concept could extend beyond diamond. The authors write that inverse-designed structures producing subwavelength photonic nanojets should also apply to other semiconductor materials containing emitters and could be generalized to fiber-integrated platforms. That leaves the next step less about announcing a device product and more about testing the geometry across other materials and integration schemes already named in the paper. (science.org)