{"id":846863,"date":"2026-08-07T14:18:20","date_gmt":"2026-08-07T14:18:20","guid":{"rendered":"https:\/\/www.newsbeep.com\/au\/846863\/"},"modified":"2026-08-07T14:18:20","modified_gmt":"2026-08-07T14:18:20","slug":"researchers-generate-quantum-entanglement-using-sunlight","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/au\/846863\/","title":{"rendered":"Researchers generate quantum entanglement using sunlight"},"content":{"rendered":"

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Using a new cone-shaped solar concentrator, researchers showed that sunlight can be used to create entangled photons. This could one day enable satellites to create secure encryption keys using the sunlight already abundant in space<\/p>\n

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Credit: Florian Sterl<\/p>\n

WASHINGTON \u2014 Today\u2019s quantum technologies rely on energy-intensive lasers, raising concerns that scaling them up could further increase energy demands. In new work, researchers have demonstrated that quantum entanglement between photons can be generated directly from sunlight, offering a potential alternative.<\/p>\n

\u201cQuantum entanglement is crucial for applications such as secure communication, ultra-precise sensing and high-performance computation,\u201d said Cheng Li, a recent graduate of the University of Ottawa<\/a> in Canada. \u201cOur work shows that abundant natural light sources can be used for quantum entanglement, opening the possibility of more energy-efficient and accessible quantum technologies.\u201d<\/p>\n

In Optica<\/a>, Optica Publishing Group<\/a>\u2019s<\/a> journal for high-impact research, the researchers report that the entanglement they achieved using sunlight was comparable to laser-based approaches after accounting for differences in the bandwidth of the input light.. The advance combined theoretical advances from Robert Boyd\u2019s team at the University of Ottawa with a new solar concentrator developed by Hanieh Fattahi\u2019s team at the Max Planck Institute for the Science of Light<\/a> (MPL) in Germany.<\/p>\n

\u201cThis technology could one day enable satellites to create secure encryption keys using the sunlight already abundant in space, reducing the need for onboard lasers and much of the supporting hardware,\u201d said Li, first author of the paper. \u201cSunlight-driven entanglement generation could also provide the crucial ingredient needed to scale up quantum computing without adding to the energy burden.\u201d<\/p>\n

Rethinking quantum light sources<\/p>\n

For some time, scientists have thought that the strong correlations required to achieve photon entanglement could only be achieved with coherent light \u2014 meaning that the light waves stay synchronized, with their peaks and valleys aligned in a predictable pattern. This is why lasers, which produce highly coherent light in a single color, are typically used to create entangled photons.<\/p>\n

In earlier work, Boyd\u2019s team theoretically predicted and experimentally observed that incoherent light can produce quantum entanglement. Their experiments used an LED, which produces incoherent light, to generate polarization-entangled photons. This laid an important foundation by showing that light can remain disordered in one property \u2014 such as the directions it travels \u2014 while still producing photons that are entangled in another property, such as their polarization.<\/p>\n

The research reported in the Optica paper takes this idea a step further by using sunlight, which is highly divergent and encompasses a broad range of colors. To create entanglement, the researchers used spontaneous parametric down-conversion (SPDC), a well-known process in which a pump beam interacts with a nonlinear crystal, causing individual photons to split into pairs that can become quantum entangled.<\/p>\n

Instead of the traditional laser-based pump beam, they used sunlight that was highly polarized but still highly incoherent in space and time. In other words, the overall field of sunlight oscillated in the same direction but contained different-colored photons that could propagate in various directions.<\/p>\n

\u201cWe designed our experimental setup so that differences introduced by the different colors and propagation directions didn\u2019t influence the photons’ polarization,\u201d said Li. \u201cAs our theory predicts, if the entanglement lives only in polarization, then it should only depend on the pump\u2019s orderliness in its oscillation direction and not on its direction or color. This allowed us to produce high-quality polarization entanglement from highly spatially and temporally incoherent sunlight.\u201d<\/p>\n

Another challenge was how to focus sunlight onto a tiny millimeter-sized nonlinear crystal. To solve this problem, Fattahi’s team at MPL developed an all-glass solar concentrator. The cone-shaped device concentrates sunlight collected by a household window-sized Fresnel lens into an optical fiber the width of a human hair, allowing it to be focused onto the tiny nonlinear crystal that drives entanglement generation.<\/p>\n

Putting the theory to the test<\/p>\n

To test their theory and the solar concentrator, the researchers conducted an outdoor experiment at MPL. Using quantum state tomography to characterize the resulting quantum state, they found that the entanglement generated from sunlight was about 94% similar to a perfectly entangled state. Additionally, the photons produced during the experiment were correlated in such a way that violates Bell’s inequality, indicating that the correlation has no classical explanation and must be a result of quantum entanglement.<\/p>\n

Now that the proof-of-principle demonstration is complete, the researchers are working toward a field-deployable product by making improvements in brightness and the quality of entanglement.<\/p>\n

Although this work used SPDC, the researchers say that the approach could be extended to other nonlinear optical methods, such as four-wave mixing, potentially opening new directions in quantum photonics research.<\/p>\n

\u201cSince the inception of this project, our idea has met with repeated doubt and pushback,\u201d said Li. \u201cSome world-renowned researchers in the field even questioned whether it would be possible to detect any photons \u2014 not to mention entangled photons \u2014 from sunlight-driven nonlinear optical processes. However, we trusted our calculations, continued improving the experimental setup and eventually showed that it was possible.\u201d<\/p>\n

Method of Research<\/p>\n

Experimental study<\/p>\n

Subject of Research<\/p>\n

Not applicable<\/p>\n

Article Publication Date<\/p>\n

6-Aug-2026<\/p>\n

Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.<\/p>\n","protected":false},"excerpt":{"rendered":"image:\u00a0 Using a new cone-shaped solar concentrator, researchers showed that sunlight can be used to create entangled photons.…\n","protected":false},"author":2,"featured_media":846864,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[24],"tags":[64,63,292,128],"class_list":["post-846863","post","type-post","status-publish","format-standard","has-post-thumbnail","category-physics","tag-au","tag-australia","tag-physics","tag-science"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/posts\/846863","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/comments?post=846863"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/posts\/846863\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/media\/846864"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/media?parent=846863"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/categories?post=846863"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/tags?post=846863"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}