Science Advances posts photon extraction paper

Science Advances published a paper on May 20 detailing a way to improve photon extraction from quantum emitters embedded in bulk semiconductors, according to the journal’s website. The study, “Probing individual quantum emitters in bulk semiconductors via photonic nanojets,” was led by Behrooz Semnani and Michal Bajcsy and appeared in volume 12 of the journal. The authors said the work uses inverse-designed nanostructures to generate photonic nanojets inside high–refractive index materials. They reported that the approach can both isolate individual emitters and raise the number of photons collected from them. ### Why is photon extraction a problem in bulk materials? The paper says bulk semiconductor hosts such as diamond trap much of the light emitted by quantum defects because of their high refractive index. That makes photon collection inefficient, even when the emitters themselves are useful for quantum information processing, telecommunications and sensing. The authors also wrote that isolating a single emitter in bulk materials often requires high-purity samples and precise defect implantation, which adds fabrication complexity. (science.org) Science Advances’ paper frames that bottleneck as a hardware issue for quantum devices that rely on stable single-photon sources or optically addressable spin defects. In the case discussed in the paper, the target system was the negatively charged nitrogen-vacancy, or NV-, center in diamond, a defect platform already used for spin control and optical readout. ### What did the researchers build? The authors reported designing monolithic photonic structures inside high-index materials using free-form topology optimization. (science.org) Those structures were fabricated with standard top-down patterning techniques, the paper said, and were built to generate tightly confined photonic nanojets. The paper says those nanojets let the team selectively excite individual emitters from a relatively dense and randomly distributed ensemble. (science.org) The same structures also suppressed background photoluminescence from near-surface defects and other emitters in the bulk, which the authors said improved the signal-to-noise ratio. ### What were the main experimental results? The researchers used NV- centers in a low-cost diamond sample at room temperature as their case study. (science.org) In that setup, they achieved selective single-emitter excitation with a 10-fold power enhancement and more than 15-fold improvement in photon extraction efficiency for photoluminescence collection in confocal microscopy, according to the paper. The supplementary materials posted by Science Advances include additional design details, methods and figures labeled S1 through S11. (science.org) The supplement identifies Semnani and Bajcsy as corresponding authors and outlines the nanojet design process used to reach the final structures. ### Who wrote the paper and where was it published? Science Advances lists Behrooz Semnani, Sai Sreesh Venuturumilli, Mohammad Soltani, Pratik Adhikary, Abdolreza Pasharavesh, Nikolay Videnov, Paul Anderson, Supratik Sarkar, Vinodh Raj Rajagopal Muthu and Michal Bajcsy as authors. (science.org) The journal page identifies the article as open access under a Creative Commons Attribution license. The article was published on May 20, 2026, according to the journal record. (science.org) A Science Advances social-media post on May 21 highlighted the study as work on photon extraction for scalable quantum technologies in bulk materials. ### What comes next in the paper itself? The authors wrote that the approach is not limited to NV centers in diamond. The paper says inverse-designed structures that generate subwavelength photonic nanojets could be applied to other semiconductor materials containing emitters and could be generalized to fiber-integrated platforms. (science.org) That next-step claim appears in the published article and accompanying supplementary file now available through Science Advances. (science.org)