{"id":197729,"date":"2025-11-24T14:40:15","date_gmt":"2025-11-24T14:40:15","guid":{"rendered":"https:\/\/www.europesays.com\/ie\/197729\/"},"modified":"2025-11-24T14:40:15","modified_gmt":"2025-11-24T14:40:15","slug":"single-photon-switch-could-enable-photonic-computing","status":"publish","type":"post","link":"https:\/\/www.europesays.com\/ie\/197729\/","title":{"rendered":"Single-Photon Switch Could Enable Photonic Computing"},"content":{"rendered":"<p><strong>Insider Brief<\/strong><\/p>\n<ul class=\"wp-block-list\">\n<li>Purdue University researchers have demonstrated a single-photon photonic transistor, enabling light-based switching at ultralow power levels.<\/li>\n<li>The device leverages avalanche multiplication in commercial SPADs to achieve nonlinear optical effects strong enough for single-photon control of powerful optical beams.<\/li>\n<li>The approach operates at room temperature, is CMOS-compatible, and could scale to gigahertz\u2013hundreds-of-gigahertz speeds for future photonic and quantum computing systems.<\/li>\n<\/ul>\n<p>There are few technologies more fundamental to modern life than the ability to control light with precision. From fiber-optic communications to quantum sensors, the manipulation of photons underpins much of our digital infrastructure. Yet one capability has remained frustratingly out of reach: controlling light with light itself at the most fundamental level using single photons to switch or modulate powerful optical beams.<\/p>\n<p>Now, researchers at Purdue University have achieved this long-sought milestone, demonstrating what they call a \u201cphotonic transistor\u201d that operates at single-photon intensities. Their findings, published in the journal\u00a0<a href=\"https:\/\/www.nature.com\/articles\/s41565-025-02056-2\" rel=\"nofollow noopener\" target=\"_blank\">Nature Nanotechnology<\/a>, report a nonlinear refractive index several orders of magnitude higher than the best-known materials, a leap that could finally make photonic computing practical.<\/p>\n<p>\u201cWe demonstrated a way to realize a photonic transistor working at single-photon intensities. This was a long-standing problem, and we found a potential way of solving it.\u201d \u2014 said\u00a0<a href=\"https:\/\/engineering.purdue.edu\/ECE\/People\/ptProfile?resource_id=3322\" rel=\"nofollow noopener\" target=\"_blank\">Vladimir Shalaev<\/a>, Purdue\u2019s Bob and Anne Burnett Distinguished Professor in Electrical and Computer Engineering. <\/p>\n<p><a href=\"https:\/\/thequantuminsider.com\/data\/\" onclick=\"_gs(&#039;event&#039;, &#039;DATA IN CONTENT NEW&#039;)\" class=\"responsive-image\" rel=\"nofollow noopener\" target=\"_blank\"><img decoding=\"async\" src=\"https:\/\/www.europesays.com\/ie\/wp-content\/uploads\/2025\/10\/Website-Banner-Quantum-2.gif\" alt=\"Responsive Image\"\/><\/a><\/p>\n<p>The achievement addresses a fundamental challenge in photonics: Traditional optical nonlinearity, where one beam of light affects another, requires enormous power levels.<\/p>\n<p>\u201cUsually there is optical nonlinearity, which allows two beams to interact with each other. But typically, this interaction works only for macroscopic beams, for classical light, because the nonlinear refractive index is very small. This is a problem because this method cannot be used for single photons.\u201d \u2014 said <a href=\"https:\/\/scholar.google.ru\/citations?user=VdDc2-sAAAAJ&amp;hl=en\" rel=\"nofollow noopener\" target=\"_blank\">Demid Sychev<\/a>, a postdoctoral researcher and the first author of this paper.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" width=\"766\" height=\"508\" src=\"https:\/\/www.europesays.com\/ie\/wp-content\/uploads\/2025\/11\/image-7.png\" alt=\"\" class=\"wp-image-2382560\" style=\"width:790px;height:auto\"  \/>Demid Sychev, a postdoctoral researcher in Shalaev\u2019s group and the first author of this paper, is seen in the reflection of one of many mirrors in Shalaev\u2019s nanophotonics laboratory.<\/p>\n<p><strong>Amplifying the quantum world<\/strong><\/p>\n<p>The solution came from an unexpected source: the avalanche multiplication process used in commercial single-photon detectors. When a single photon strikes silicon and creates a single electron, that electron can trigger an avalanche that generates up to 1 million new electrons, a cascade that bridges the microscopic quantum world with macroscopic, measurable effects.<\/p>\n<p>\u201cThis multiplication is a very powerful tool for connecting the microscopic quantum world with the macroscopic world. This principle was often used for single-photon detection, but what we did was apply this process to create a huge nonlinearity for optical beams, where one single-photon beam can control a huge macroscopic beam.\u201d \u2014 said Sychev.<strong> <\/strong><\/p>\n<p>Peigang Chen, a fourth-year PhD student in Shalaev\u2019s group, noted the elegance of the approach. \u201cWhen I first came to the group, I just thought this was a genius idea from Demid. In the future, we\u2019re going to fabricate our own single-photon avalanche diodes (SPAD) for this specific design. But the easiest way for us to get this first result was to use a commercial SPAD.\u201d \u2014 said Peigang Chen.<\/p>\n<p>The device functions as an optical switch: A single photon in the control beam can modulate the properties of a much more powerful probe beam, effectively switching it on or off.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" width=\"769\" height=\"504\" src=\"https:\/\/www.europesays.com\/ie\/wp-content\/uploads\/2025\/11\/image-8.png\" alt=\"\" class=\"wp-image-2382561\" style=\"width:793px;height:auto\"  \/>Peigang Chen, a fourth-year PhD student in Shalaev\u2019s group.<\/p>\n<p><strong>Three critical advantages<\/strong><\/p>\n<p>The Purdue team\u2019s approach offers three key advantages over alternative methods that have been explored for single-photon nonlinearity:<\/p>\n<ul class=\"wp-block-list\">\n<li>First \u2014 it operates at room temperature. \u201cTypically, what people use for single-photon nonlinearity these days are quantum systems where they use two-level systems, like a single-photon emitter coupled to a cavity,\u201d Sychev<strong> <\/strong>said. \u201cBut this method is very sensitive to temperature. It cannot be applied at room temperature.\u201d<\/li>\n<li>Second \u2014 the technology is compatible with complementary metal-oxide-semiconductor, meaning it can be integrated into existing semiconductor manufacturing processes. \u201cThis is seamless and compact,\u201d Chen<strong> <\/strong>said. \u201cFor the others, it\u2019s very different and complicated physics systems. This one is semiconductor, and it can always be fabricated on chip.\u201d<\/li>\n<li>Third \u2014 and perhaps most importantly, it operates at gigahertz speeds and could potentially reach hundreds of gigahertz, dramatically faster than existing approaches. \u201cClock rates of such systems may go up to gigahertz, but with the methods we developed, in principle, it can be extended to hundreds of gigahertz,\u201d Sychev said.<\/li>\n<\/ul>\n<p><strong>Applications: From quantum to classical<\/strong><\/p>\n<p>While the research has obvious applications in quantum computing, where it could increase the efficiency of generating single photons and enable faster quantum teleportation protocols, Sychev believes classical computing applications may be even more transformative.<\/p>\n<p>he said \u2014 \u201cThe reason why a photonic computer is not realized is because the current approaches using photons are supposed to be much better. Photons consume less energy; they are faster,. Ideally, from photons, you can get terahertz clock rates of CPUs, compared to currently existing 5 gigahertz in the best cases. But the problem is that there are no photonic switches like this. The needed interaction between photons typically requires high powers of optical light. With our method, in principle, you can do it with single photons.\u201d<\/p>\n<p>The implications extend beyond computing to data centers, optical communications and data transfer systems \u2014 anywhere that the speed and energy efficiency of photons could replace slower, more power-hungry electronics.<\/p>\n<p>\u201cI feel like here I\u2019m starting to change the world, this work really means a lot, not only for my career, but also because this device can make a difference in the industry and the science community.\u201d \u2014 said Chen.<\/p>\n<p><strong>A four-year journey into unknown territory<\/strong><\/p>\n<p>The path from concept to publication was neither quick nor straightforward. Sychev had been working on the idea for about a year when Chen joined the group three years ago. Over four years, the team tried several different experiments before achieving success.<\/p>\n<p>\u201cIt was an iterative process, it took a lot of experimental efforts because it\u2019s completely unknown territory.\u201d Sychev said.<\/p>\n<p>The work was conducted at Purdue\u2019s Birck Nanotechnology Center under the guidance of professors Shalaev and\u00a0<a href=\"https:\/\/engineering.purdue.edu\/ECE\/People\/ptProfile?resource_id=46150\" rel=\"nofollow noopener\" target=\"_blank\">Alexandra Boltasseva<\/a>, the Ron and Dotty Garvin Tonjes Distinguished Professor in Electrical and Computer Engineering. Both Sychev and Chen are affiliated with the\u00a0<a href=\"https:\/\/quantum.research.purdue.edu\/\" rel=\"nofollow noopener\" target=\"_blank\">Purdue Quantum Science and Engineering Institute<\/a>.<\/p>\n<p><strong>Next steps and broader impact<\/strong><\/p>\n<p>The team is now focused on optimizing the technology. They plan to explore different device geometries and materials to further enhance performance.<\/p>\n<p>\u201cPreviously, all commercially available SPADs we used were not designed for this purpose, now our goal is to make a device which will be optimized to work as a single-photon switch.\u201d \u2014 said Sychev.<\/p>\n<p>Sychev emphasized that while the demonstration is significant, substantial work remains. <\/p>\n<p>\u201cThis work indeed can bring more results in the future for industry and for academia, for science and technology, It\u2019s a long-standing problem, and we found some potential way of solving that problem. It still requires a lot of work toward this goal, but at least some interesting direction was found, and we are very happy about this.\u201d \u2014 said Sychev.<\/p>\n<p>The research team also includes Yuheng Chen, Morris Yang and Colton Fruhling, all from Purdue\u2019s Elmore Family School of Electrical and Computer Engineering, who performed optical measurements alongside Sychev and Chen. Alexei Lagutchev, a senior research scientist at the Birck Nanotechnology Center, conceived and planned the experiments and analyzed the experimental data. Alexander Kildishev, a professor of electrical and computer engineering at Purdue, performed finite-element simulations to support the work.<\/p>\n<p>The researchers believe their breakthrough has created what Shalaev and Boltasseva have described in related work as a new \u201cplayground\u201d for physics and engineering, a platform where fundamental discoveries in controlling light at its most basic level can lead to transformative applications across quantum and classical technologies. As the demand for faster, more efficient computing and communication systems continues to grow, the ability to manipulate photons at the single-photon level represents a critical step toward realizing the full potential of light-based technologies.<\/p>\n<p>Quantum research is a pillar of\u00a0<a href=\"https:\/\/www.purdue.edu\/computes\/\" rel=\"nofollow noopener\" target=\"_blank\">Purdue Computes<\/a>, a strategic university initiative to further scale Purdue\u2019s research and educational excellence in computing.<\/p>\n<p>The paper acknowledges cooperative research with DEVCOM Army Research Laboratory supported by ACC-APG-RTP Agency. \u00a0A provisional patent application related to this work has been filed by the\u00a0<a href=\"https:\/\/purdueinnovates.org\/\" rel=\"nofollow noopener\" target=\"_blank\">Purdue Innovates Office of Technology Commercialization<\/a>.<\/p>\n<p><strong>Source: <a href=\"https:\/\/engineering.purdue.edu\/Engr\/AboutUs\/News\/Spotlights\/2025\/2025-1120-Single-photon-switch-could-enable-photonic-computing\" rel=\"nofollow noopener\" target=\"_blank\">Purdue University<\/a><\/strong><\/p>\n","protected":false},"excerpt":{"rendered":"Insider Brief Purdue University researchers have demonstrated a single-photon photonic transistor, enabling light-based switching at ultralow power levels.&hellip;\n","protected":false},"author":2,"featured_media":197730,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[74],"tags":[18,19,17,109761,54307,109762,109763,82],"class_list":{"0":"post-197729","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-technology","8":"tag-eire","9":"tag-ie","10":"tag-ireland","11":"tag-optical-switching","12":"tag-purdue-university","13":"tag-semiconductor-photonics","14":"tag-single-photon-devices","15":"tag-technology"},"share_on_mastodon":{"url":"https:\/\/pubeurope.com\/@ie\/115605197811621562","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts\/197729","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=197729"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts\/197729\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/media\/197730"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/media?parent=197729"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/categories?post=197729"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/tags?post=197729"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}