{"id":623723,"date":"2026-08-06T15:01:09","date_gmt":"2026-08-06T15:01:09","guid":{"rendered":"https:\/\/www.europesays.com\/ie\/623723\/"},"modified":"2026-08-06T15:01:09","modified_gmt":"2026-08-06T15:01:09","slug":"researchers-generate-quantum-entanglement-directly-from-sunlight","status":"publish","type":"post","link":"https:\/\/www.europesays.com\/ie\/623723\/","title":{"rendered":"Researchers generate quantum entanglement directly from sunlight"},"content":{"rendered":"

\"Using<\/a>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

Credit Florian Sterl
\n Researchers from the University of Ottawa and the Max Planck Institute for the Science of Light have generated quantum entanglement using natural sunlight, demonstrating a viable, energy efficient alternative to power future quantum technology systems
\nAddressing the energy demands of quantum systems<\/p>\n

Modern quantum technologies rely on energy-intensive laser systems to generate entangled photon pairs, which are essential for applications in ultra-secure communication, high-precision sensing, and quantum computing. As these systems expand, their growing energy consumption presents a major bottleneck for widespread adoption and orbital deployments.<\/p>\n

To overcome this limitation, a joint research team demonstrated that natural light sources can produce quantum-entangled photons directly.<\/a> Published in the journal Optica, the study proves that abundant sunlight can yield entanglement quality comparable to conventional laser-driven approaches after accounting for spectral bandwidth differences.<\/p>\n

Overcoming coherence assumptions in quantum optics<\/p>\n

For decades, conventional optical theory held that generating strong quantum correlations required highly coherent light waves, such as those produced by single-colour lasers with aligned phase patterns. However, recent theoretical work from the University of Ottawa demonstrated that disordered, incoherent light can still yield entangled photon pairs.<\/p>\n

Building on prior experiments that used incoherent light from light-emitting diodes, the researchers applied spontaneous parametric down-conversion to natural sunlight. Spontaneous parametric down-conversion is a non-linear process where individual incoming pump photons split into entangled photon pairs inside a non-linear crystal.<\/p>\n

Sunlight is highly divergent and contains a broad spectrum of colours, but the team designed an optical configuration where colour variations and propagation angles did not disrupt the polarisation states of the emitted photons, successfully isolating pure polarisation entanglement<\/a>.<\/p>\n

Solar concentration engineering for small crystals<\/p>\n

Focusing natural sunlight onto a tiny, millimetre-sized non-linear crystal required specialised optical engineering. A team at the Max Planck Institute for the Science of Light developed an all-glass solar concentrator to solve the spatial delivery challenge.<\/p>\n

The setup uses a window-sized Fresnel lens to collect ambient sunlight, which is then funnelled through a cone-shaped glass device into a thin optical fibre no wider than a human hair. This optical fibre directs concentrated, highly polarised sunlight onto the non-linear crystal to trigger the down-conversion process.<\/p>\n

Outdoor validation and quantum fidelity<\/p>\n

To confirm the validity of their theoretical models, the researchers conducted outdoor field tests. Using quantum state tomography to reconstruct the generated quantum state, the team measured a 94 per cent state fidelity compared to an ideal entangled state.<\/p>\n

Furthermore, the photon pairs demonstrated correlations that violated Bell\u2019s inequality. This violation serves as strict physical proof that the observed photon relationships stem from true quantum entanglement<\/a> rather than classical optical effects.<\/p>\n

Satellite encryption and future extensions<\/p>\n

Generating entangled photons directly from sunlight holds immediate promise for space-based quantum communication networks. Satellites equipped with solar concentrators could generate secure encryption keys using ambient solar radiation, eliminating the need for heavy onboard lasers and power supplies.<\/p>\n

The research team plans to refine the experimental setup to increase photon generation brightness and entanglement quality. Additionally, researchers noted that the solar concentration approach could be adapted to other non-linear optical processes, such as four-wave mixing, creating new pathways for sustainable quantum photonics.<\/p>\n","protected":false},"excerpt":{"rendered":"Using a new cone-shaped solar concentrator, researchers showed that sunlight can be used to create entangled photons. This…\n","protected":false},"author":2,"featured_media":623724,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":"","_share_on_mastodon":"0"},"categories":[74],"tags":[18,19,17,317,56294,82],"class_list":["post-623723","post","type-post","status-publish","format-standard","has-post-thumbnail","category-technology","tag-eire","tag-ie","tag-ireland","tag-quantum","tag-research-and-science-funding","tag-technology"],"share_on_mastodon":{"url":"","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts\/623723","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/comments?post=623723"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts\/623723\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/media\/623724"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/media?parent=623723"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/categories?post=623723"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/tags?post=623723"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}