tag:theconversation.com,2011:/africa/topics/night-vision-5721/articlesNight vision – The Conversation2022-12-21T13:42:42Ztag:theconversation.com,2011:article/1969202022-12-21T13:42:42Z2022-12-21T13:42:42ZReindeer eyes change color, putting Rudolph’s red nose in the shade – new research podcast<figure><img src="https://images.theconversation.com/files/502245/original/file-20221220-22-ecence.jpg?ixlib=rb-1.1.0&rect=562%2C1059%2C2994%2C1934&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Reindeer have adapted to the dim, blue light of the Arctic winter.</span> <span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Reindeer_in_Winter_-_geograph.org.uk_-_3371243.jpg#/media/File:Reindeer_in_Winter_-_geograph.org.uk_-_3371243.jpg">Alice/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>Reindeer noses may not glow red, but these creatures of cold climes have evolved the ability to change the color of their eyes to help them thrive in dark, northern winters. In this Discovery episode, we speak with <a href="https://scholar.google.com/citations?user=UYlObKkAAAAJ&hl=en&oi=ao">Glen Jeffery</a>, a professor of neuroscience at the Institute of Opthamology at UCL (University College London) in the U.K. about what makes reindeer eyes truly unique in the animal kingdom. </p>
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<p>Most people have seen the gold, glowing eyes of a cat, a raccoon or some other nocturnal animal staring back at them during a nighttime drive. The part of the eye that produces that golden reflection, as Jeffery explains, “is a mirror that lots of animals have called the tapetum lucidum.” A taptetum helps animals see better in the dark by bouncing light from the back of the eye through the retina a second time. In most mammals, the tapetum is a “standard golden,” as Jeffery describes the color, and that color doesn’t change.</p>
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<a href="https://images.theconversation.com/files/502246/original/file-20221220-12-k4w2js.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A photo of a raccoon with glowing, gold eyes." src="https://images.theconversation.com/files/502246/original/file-20221220-12-k4w2js.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/502246/original/file-20221220-12-k4w2js.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=514&fit=crop&dpr=1 600w, https://images.theconversation.com/files/502246/original/file-20221220-12-k4w2js.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=514&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/502246/original/file-20221220-12-k4w2js.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=514&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/502246/original/file-20221220-12-k4w2js.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=645&fit=crop&dpr=1 754w, https://images.theconversation.com/files/502246/original/file-20221220-12-k4w2js.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=645&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/502246/original/file-20221220-12-k4w2js.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=645&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Many animals’ eyes shine in the darkness because of a reflective layer called the tapetum lucidum that is usually gold.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Raccoon_red_eye.JPG#/media/File:Raccoon_red_eye.JPG">Bowlhover/Wikimedia Commons</a></span>
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<p>One day, Jeffery received a box in the mail out of the blue. It contained two jars filled with reindeer eyes from a slaughterhouse in Norway. One jar was labeled summer and one was labeled winter.</p>
<p>“I opened up the summer ones first and I thought, ‘I’m wasting my time here,’” says Jeffery. He saw golden eyes, just what he expected.</p>
<p>“But then we opened up the other eyes, and that was when there was a shock, because the winter eyes were blue,” he said. “I’d never seen anything like that in my life.”</p>
<p>Jeffery and his colleagues spent years studying the biology of reindeer eyes and the environment they are made for – the dim, blue-hued months of the Arctic winter. What they discovered is a marvelous bit of evolution that has given reindeer some of the most interesting eyes on Earth. Listen to this Discovery episode of the Conversation to hear about how Jeffery and his colleagues study reindeer eyes, why winter eyes are such a unique color and how light pollution can alter this finely tuned adaptation.</p>
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<p>This episode was written and produced by Katie Flood with Gemma Ware and hosted by Dan Merino. Eloise Stevens does our sound design, and our theme music is by Neeta Sarl.</p>
<p>You can find us on Twitter <a href="https://twitter.com/TC_Audio">@TC_Audio</a>, on Instagram at <a href="https://www.instagram.com/theconversationdotcom/">theconversationdotcom</a> or <a href="mailto:podcast@theconversation.com">via email</a>. You can also sign up to The Conversation’s <a href="https://theconversation.com/newsletter">free daily email here</a>. A transcript of this episode is <a href="https://cdn.theconversation.com/static_files/files/2795/Discovery_Ep3_Reindeer_Eyes_Transcript.pdf?1694453126">now available</a>.</p>
<p>Listen to “The Conversation Weekly” via any of the apps listed above, download it directly via our <a href="https://feeds.acast.com/public/shows/60087127b9687759d637bade">RSS feed</a> or find out <a href="https://theconversation.com/how-to-listen-to-the-conversations-podcasts-154131">how else to listen here</a>.</p><img src="https://counter.theconversation.com/content/196920/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Glen Jeffery receives funding from the Biotechnology and Biological Sciences Research Council of the UK.</span></em></p>In winter, light in the northern latitudes is dim and very blue compared to summer light. Reindeer eyes have evolved to be better suited at seeing in this unique environment.Daniel Merino, Associate Science Editor & Co-Host of The Conversation Weekly Podcast, The ConversationLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1626152021-06-16T07:00:52Z2021-06-16T07:00:52ZSeeing the invisible: tiny crystal films could make night vision an everyday reality<figure><img src="https://images.theconversation.com/files/406613/original/file-20210616-3738-1hg0363.png?ixlib=rb-1.1.0&rect=8%2C2%2C902%2C444&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Artist's impression of the view through future night-vision glasses.</span> <span class="attribution"><span class="source">Lei Xu / NTU</span>, <span class="license">Author provided</span></span></figcaption></figure><p>It’s a familiar vision to anyone who has watched a lot of action movies or played Call of Duty: a ghostly green image that makes invisible objects visible. Since the development of the first night-vision devices in the mid-1960s, the technology has captured the popular imagination.</p>
<p>Night vision goggles, infrared cameras and other similar devices detect infrared light reflected from objects or rather detect infrared light emitted from objects in the form of heat. Today these devices are widely used not only by the military, but also by law enforcement and emergency services, the security and surveillance industries, wildlife hunters, and camping enthusiasts.</p>
<p>But current technology is not without its problems. Commercial infrared cameras block visible light, disrupting normal vision. The gear is bulky and heavy, and requires low temperatures — and, in some cases, even cryogenic cooling — to work.</p>
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<img alt="" src="https://images.theconversation.com/files/406606/original/file-20210616-15-1skecj7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/406606/original/file-20210616-15-1skecj7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/406606/original/file-20210616-15-1skecj7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/406606/original/file-20210616-15-1skecj7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/406606/original/file-20210616-15-1skecj7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/406606/original/file-20210616-15-1skecj7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/406606/original/file-20210616-15-1skecj7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Rocio Camacho Morales in the optics lab.</span>
<span class="attribution"><span class="source">Jamie Kidston / ANU</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>We have proposed a new technology that uses ultra-thin layers of nanocrystals to make infrared light visible, addressing many of the longstanding problems with current devices. Our research is published in <a href="https://doi.org/10.1117/1.AP.3.3.036002">Advanced Photonics</a>. </p>
<p>Our eventual goal is to produce a light, film-like layer that can sit on glasses or other lenses, powered by a tiny built-in laser, allowing people to see in the dark.</p>
<h2>Conventional infrared detection</h2>
<p>Commercial infrared cameras convert infrared light to an electric signal, which is then shown on a display screen. They require low temperatures, because of the low energy and frequency of infrared light. This makes conventional infrared detectors bulky and heavy – some security personnel have reported
chronic neck injury due to <a href="https://doi.org/10.3357/AMHP.4027.2015">regular use of night vision goggles</a> . </p>
<p>Another drawback of the current technology is that it blocks the transmission of visible light, thereby disrupting normal vision. In some cases, infrared images could be sent to a display monitor, leaving normal vision intact. However, this solution is not feasible when users are on the move.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/looking-at-the-universe-through-very-different-eyes-86068">Looking at the universe through very different 'eyes'</a>
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<h2>All-optical alternatives</h2>
<p>There are also some all-optical <a href="https://doi.org/10.1063/1.1651902">alternatives</a>, which do not involve electrical signals. Instead, they directly convert infrared light into visible light. The visible light can then be captured by the eye or a camera.</p>
<p>These technologies work by combining incoming infrared light with a strong light source – a laser beam – inside a material known as “nonlinear crystal”. The crystal then emits light in the visible spectrum. </p>
<p>However, nonlinear crystals are bulky and expensive, and can only detect light in a narrow band of infrared frequencies.</p>
<h2>Metasurfaces provide the solution</h2>
<p>Our work advances this all-optical approach. Instead of a non-linear crystal, we set out to use carefully designed layers of nanocrystal called “metasurfaces”. Metasurfaces are ultra-thin and ultra-light, and can be tweaked to manipulate the color or frequency of the light that passes through them.</p>
<p>This makes metasurfaces an attractive platform to convert infrared photons to the visible. Importantly, transparent metasurfaces could enable infrared imaging and allow for normal vision at the same time.</p>
<p>Our group set out to demonstrate infrared imaging with metasurfaces. We designed a metasurface composed of hundreds of incredibly tiny crystal antennas made of the semiconductor gallium arsenide. </p>
<p>This metasurface was designed to amplify light by resonance at certain infrared frequencies, as well as the frequency of the laser and the visible light output. We then fabricated the metasurface and transferred it to a transparent glass, forming a layer of nanocrystals on a glass surface.</p>
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<img alt="" src="https://images.theconversation.com/files/406071/original/file-20210614-23-1cjuozk.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/406071/original/file-20210614-23-1cjuozk.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=416&fit=crop&dpr=1 600w, https://images.theconversation.com/files/406071/original/file-20210614-23-1cjuozk.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=416&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/406071/original/file-20210614-23-1cjuozk.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=416&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/406071/original/file-20210614-23-1cjuozk.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=523&fit=crop&dpr=1 754w, https://images.theconversation.com/files/406071/original/file-20210614-23-1cjuozk.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=523&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/406071/original/file-20210614-23-1cjuozk.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=523&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A scanning electron microscope image shows the nanocrystal structures of the metasurface used to make infrared light visible.</span>
<span class="attribution"><span class="source">Mohsen Rahmani/ NTU</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>To test our metasurface, we illuminated it with infrared images of a target and saw that the infrared images were converted to visible green images. We tested this with various positions of the target, and also with no target at all — so we could see the green emission of the metasurface itself. In the images obtained, the dark stripes correspond to the infrared target, surrounded by the green visible emission.</p>
<p>Despite different parts of the infrared images being up-converted by independent nanocrystals composing the metasurface, the images were well reproduced in visible light.</p>
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<a href="https://images.theconversation.com/files/406072/original/file-20210614-25-1ngrt1e.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/406072/original/file-20210614-25-1ngrt1e.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/406072/original/file-20210614-25-1ngrt1e.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=367&fit=crop&dpr=1 600w, https://images.theconversation.com/files/406072/original/file-20210614-25-1ngrt1e.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=367&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/406072/original/file-20210614-25-1ngrt1e.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=367&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/406072/original/file-20210614-25-1ngrt1e.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=461&fit=crop&dpr=1 754w, https://images.theconversation.com/files/406072/original/file-20210614-25-1ngrt1e.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=461&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/406072/original/file-20210614-25-1ngrt1e.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=461&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">These pairs of images show the shape of the infrared target at left and the visible-light view through the metasurface at right.</span>
<span class="attribution"><span class="source">Rocio Camacho Morales</span>, <span class="license">Author provided</span></span>
</figcaption>
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<p>While our experiment is only a proof of concept, this technology can in principle do many things that are not possible with conventional systems, such as a broader angle of view and multi-colour infrared imaging.</p>
<h2>The future of metasurfaces in novel technologies</h2>
<p>The demand for detecting infrared light, invisible to human eyes, is constantly growing, due to a wide variety of applications beyond night vision. The technology could be used in the agricultural industry to help monitor and maintain food quality control, and in remote sensing techniques such as LIDAR – a technology that is helping to map natural and manmade environments. </p>
<p>In a wider context, the use of metasurfaces to detect, generate and manipulate light is booming. Harnessing the power of metasurfaces will bring us closer to technologies such as real-time holographic displays, artificial vision for autonomous systems, and ultra-fast light-based wifi. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/small-and-bright-what-nanophotonics-means-for-you-58747">Small and bright: what nanophotonics means for you</a>
</strong>
</em>
</p>
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<img src="https://counter.theconversation.com/content/162615/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Rocio Camacho Morales would like to acknowledge the support of the ARC Centre of Excellence for Transformative Meta-Optical Systems (TMOS) and the Consejo Nacional de Ciencia y Tecnología (CONACYT),</span></em></p>New ‘nanocrystal metasurfaces’ can convert infrared light into the visible spectrumRocio Camacho Morales, Postdoctoral fellow, ARC Center of Excellence for Transformative Meta-Optical Systems (TMOS), Australian National UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1601522021-05-06T18:12:42Z2021-05-06T18:12:42ZNocturnal dinosaurs: Night vision and superb hearing in a small theropod suggest it was a moonlight predator<figure><img src="https://images.theconversation.com/files/398999/original/file-20210505-17-16fmhv4.png?ixlib=rb-1.1.0&rect=32%2C9%2C1511%2C788&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Fossils of _Shuvuuia deserti_ depict a small predatory creature with exceptional night vision and hearing.</span> <span class="attribution"><span class="source">Mick Ellison/American Natural History Museum</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>Today, barn owls, bats, leopards and many other animals rely on their keen senses to live and hunt under the dim light of stars. These <a href="https://doi.org/10.1086/702250">nighttime specialists avoid the competition of daylight hours</a>, hunting their prey under the cloak of darkness, often using a combination of night vision and acute hearing.</p>
<p>But was there nightlife 100 million years ago? In a world without owls or leopards, were dinosaurs working the night shift? If so, what senses did they use to find food and avoid predators in the darkness? To better understand the senses of the dinosaur ancestors of birds, <a href="https://scholar.google.com/citations?user=kHIW_0cAAAAJ&hl=en&oi=ao">our team</a> of <a href="https://scholar.google.com/citations?user=6qODxwoAAAAJ&hl=en&oi=ao">paleontologists</a> and <a href="https://scholar.google.com/citations?user=m_p_Lc0AAAAJ&hl=en&oi=ao">paleobiologists</a> scoured research papers and museum collections looking for fossils that preserved delicate eye and ear structures. And we found some. </p>
<p>Using scans of fossilized dinosaur skulls, in a paper <a href="https://science.sciencemag.org/content/372/6542/610?intcmp=trendmd-sci">published in the journal Science on May 6, 2021</a>, we describe the most convincing evidence to date for nocturnal dinosaurs. Two fossil species – <em>Haplocheirus sollers</em> and <em>Shuvuuia deserti</em> – likely had extremely good night vision. But our work also shows that <em>S. deserti</em> also had incredibly sensitive hearing similar to modern-day owls. This is the first time these two traits have been found in the same fossil, suggesting that this small, desert-dwelling dinosaur that lived in ancient Mongolia was probably a specialized night-hunter of insects and small mammals.</p>
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<a href="https://images.theconversation.com/files/399011/original/file-20210505-23-hnil4h.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="An artistic reconstruction showing _S. deserti as a small, feathered bipedal dinosaur with an owlish face." src="https://images.theconversation.com/files/399011/original/file-20210505-23-hnil4h.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/399011/original/file-20210505-23-hnil4h.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=848&fit=crop&dpr=1 600w, https://images.theconversation.com/files/399011/original/file-20210505-23-hnil4h.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=848&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/399011/original/file-20210505-23-hnil4h.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=848&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/399011/original/file-20210505-23-hnil4h.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1066&fit=crop&dpr=1 754w, https://images.theconversation.com/files/399011/original/file-20210505-23-hnil4h.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1066&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/399011/original/file-20210505-23-hnil4h.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1066&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption"><em>Shuvuuia deserti</em> had acute hearing and low-light vision that would have allowed it to hunt at night.</span>
<span class="attribution"><span class="source">Viktor Radermaker</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Looking to theropods</h2>
<p>By studying fossilized eye bones, one of us, Lars Schmitz, had previously found that some small predatory dinosaurs <a href="https://doi.org/10.1126/science.1200043">may have hunted at night</a>. Most of these potentially nocturnal hunters were theropods, the group of three-toed dinosaurs that includes <em>Tyrannosaurus rex</em> and modern birds. But to date, fossils for only <a href="https://doi.org/10.1126/science.1200043">12 theropod species included the eye structures</a> that can tell paleontologists about night vision.</p>
<p>Our team identified four more species of theropods with clues for their sense of vision – for a total of 16. We then looked for fossils that preserve the structures of the inner ear and found 17 species. Excitingly, for four species, we were able to get measurements for both eyes and ears.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/399012/original/file-20210505-23-usv75o.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A close up photo of the skull of _S. deserti_ showing a large eye socket." src="https://images.theconversation.com/files/399012/original/file-20210505-23-usv75o.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/399012/original/file-20210505-23-usv75o.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=378&fit=crop&dpr=1 600w, https://images.theconversation.com/files/399012/original/file-20210505-23-usv75o.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=378&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/399012/original/file-20210505-23-usv75o.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=378&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/399012/original/file-20210505-23-usv75o.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=475&fit=crop&dpr=1 754w, https://images.theconversation.com/files/399012/original/file-20210505-23-usv75o.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=475&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/399012/original/file-20210505-23-usv75o.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=475&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The eye socket – and specifically the sclerical ring – of <em>S. deserti</em> shows an eye with a very large pupil capable of letting in large amounts of light.</span>
<span class="attribution"><span class="source">Mick Ellison/American Museum of Natural History</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Eye bones built for night vision</h2>
<p>Scleral ossicles are thin, rectangular bone plates that form a <a href="https://doi.org/10.1002/ar.24043">ring-like structure surrounding the pupils</a> of lizards as well as birds and their ancestors – dinosaurs. Scleral rings define the largest possible size of an animal’s pupil and can tell you how well that animal <a href="https://doi.org/10.1016/j.visres.2010.03.009">can see at night</a>. The larger the pupil compared to the size of the eye, the better a dinosaur could see in the dark.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/399017/original/file-20210505-19-1imtqg9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="An owl skull with a cone like ring attached to the eye socket." src="https://images.theconversation.com/files/399017/original/file-20210505-19-1imtqg9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/399017/original/file-20210505-19-1imtqg9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=456&fit=crop&dpr=1 600w, https://images.theconversation.com/files/399017/original/file-20210505-19-1imtqg9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=456&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/399017/original/file-20210505-19-1imtqg9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=456&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/399017/original/file-20210505-19-1imtqg9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=573&fit=crop&dpr=1 754w, https://images.theconversation.com/files/399017/original/file-20210505-19-1imtqg9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=573&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/399017/original/file-20210505-19-1imtqg9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=573&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">This owl skull clearly shows the large scleral ring that helps animals see in darkness.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Bubo_virginianus_8zz.jpg#/media/File:Bubo_virginianus_8zz.jpg">David J. Stang/WikimediaCommons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Since the individual bony ossicles of these rings fell apart after these animals died more than 60 million years ago, our team made scans of the fossils and then digitally reconstructed the eyes. Of all the theropods we examined, <em>H. sollers</em> and <em>S. deserti</em> had some of the proportionally largest pupils.</p>
<p><em>S. deserti</em>‘s pupil made up more than half of its eye, very similar to night-vision specialists that live today like geckos and nightjars. Our team then compared the fossils to 55 living species of lizards and 367 species of birds with known day or night activity patterns. According to the statistical analyses our team performed, there is a very high chance – higher than 90% – that <em>H. sollers</em> and <em>S. deserti</em> were nocturnal.</p>
<p>But those were not the only two theropods our team looked at. Our analysis also found a few other likely nighttime specialists – such as <em>Megapnosaurus kayentakatae</em> – as well as daylight specialists like <em>Almas ukhaa</em>. But we also found some species – like <em>Velociraptor mongoliensis</em> – with eyesight seemingly adapted for medium light levels. This might suggest that they hunted around dawn or dusk.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/399020/original/file-20210505-19-62si2q.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two white plastic molds on a black background both with an elongated vertical base splitting into a 'y' shape at the top." src="https://images.theconversation.com/files/399020/original/file-20210505-19-62si2q.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/399020/original/file-20210505-19-62si2q.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/399020/original/file-20210505-19-62si2q.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/399020/original/file-20210505-19-62si2q.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/399020/original/file-20210505-19-62si2q.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/399020/original/file-20210505-19-62si2q.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/399020/original/file-20210505-19-62si2q.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Molds of the inner ear canal from a barn owl (left) and <em>S. deserti</em> (right) are almost identical, suggesting that the small dinosaur had incredible hearing.</span>
<span class="attribution"><span class="source">Shivan Parusnath/Wits University</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Incredible ears of a dinosaur</h2>
<p>In today’s nocturnal animals, <a href="https://doi.org/10.1002/bies.201600006">hearing can be as important as keen eyesight</a>. To figure out how well these extinct dinosaurs could hear, we scanned the skulls of 17 fossil theropods to decipher the structure of their inner ears and then compared our scans to the ears of modern animals.</p>
<p>All vertebrates have a tube-like canal called the cochlea deep in their inner ear. Studies of living mammals and birds show that the longer this canal, the <a href="https://doi.org/10.1098/rspb.2008.1390">wider the range of frequencies an animal can hear</a> and the better they can hear <a href="https://doi.org/10.1098/rspb.2008.1390">very faint sounds</a>.</p>
<p>Our scans showed that <em>S. deserti</em> had an extremely elongated inner ear canal for its size – also similar to that of the living barn owl and proportionally much longer than all of the other 88 living bird species we analyzed for comparison. Based on our measurements, among dinosaurs, we found that predators had generally better hearing than herbivores. Several predators – including <em>V. mongoliensis</em> – also had moderately elongated inner ears, but none rivaled <em>S. deserti</em>’s. </p>
<h2>The life of a nocturnal dinosaur</h2>
<p>By studying the sensory abilities of dinosaurs, paleontologists like us not only are learning what species roamed the night, but can also begin to infer how these dinosaurs lived and shared resources.</p>
<p><a href="https://doi.org/10.1126/science.abe7941"><em>S. deserti</em> had extreme night vision and sensitive hearing</a>, and this little dinosaur probably used its incredible senses to hunt prey at night. It could likely hear and follow rustling from a distance before visually detecting its prey and digging it up from the ground with its short single-clawed arms. In the dry, desert-like habitats of millions of years ago, it might have been an evolutionary advantage to be active in the cooler temperatures of the night. </p>
<p>But according to our analysis, <em>S. deserti</em> wasn’t the only dinosaur active at night. Other dinosaurs like <em>V. mongoliensis</em> and the plant-eating <em>Protoceratops mongoliensis</em> both lived in the same habitat and had some level of night vision.</p>
<p>Paleontologists currently do not know the full suite of animals that shared <em>S. deserti</em>’s extreme nocturnal lifestyle in the ancient deserts of Mongolia – it is rare to find fossils with the right bones intact that allow paleontologists to investigate their senses. However, the presence of a specialized night forager highlights that much like today, some dinosaurs avoided the dangers and competition of daylight hours and roamed under the stars.</p>
<p>[<em>Get the best of The Conversation, every weekend.</em> <a href="https://theconversation.com/us/newsletters/weekly-highlights-61?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=weeklybest">Sign up for our weekly newsletter</a>.]</p><img src="https://counter.theconversation.com/content/160152/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jonah Choiniere receives funding from the National Research Foundation of South Africa. </span></em></p><p class="fine-print"><em><span>Roger Benson receives funding from the European Research Council, National Environments Research Council and Leverhulme Trust. </span></em></p><p class="fine-print"><em><span>Lars Schmitz does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>By looking at the eye bones and ear canals of extinct dinosaurs, researchers show that a small ancient predator likely hunted at night and had senses as good as a modern barn owl.Lars Schmitz, Associate Professor of Biology, Scripps CollegeJonah Choiniere, Professor of Dinosaur Paleontology, University of the WitwatersrandRoger Benson, Professor of Palaeobiology, University of OxfordLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/741012017-03-13T12:12:31Z2017-03-13T12:12:31ZHow do animals see in the dark?<figure><img src="https://images.theconversation.com/files/160493/original/image-20170313-19270-be2f9q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">_Megalopta genalis_.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/usgsbiml/15121397069/">United States Geological Survey</a></span></figcaption></figure><p>On a moonless night, light levels can be more than 100m times <a href="http://bit.ly/2mZLkEL">dimmer than in bright daylight</a>. Yet while we are nearly blind and quite helpless in the dark, cats are out stalking prey, and moths are flying agilely between flowers on our balconies.</p>
<p>While we sleep, millions of other animals rely on their visual systems to survive. The same is true of animals who inhabit the eternal darkness of the deep sea. In fact, the overwhelming majority of the world’s animals are primarily active in dim light. How is their formidable visual performance possible, especially in insects, with tiny eyes and brains less than the size of a grain of rice? What optical and neural strategies have they evolved to allow them to see so well in dim light?</p>
<p>To answer these questions, we turned our attentions to nocturnal insects. Despite their diminutive visual systems, it turns out that nocturnal insects see amazingly well in dim light. In recent years we have discovered that nocturnal insects can avoid and fixate on obstacles <a href="http://science.sciencemag.org/content/348/6240/1245">during flight</a>, <a href="http://www.nature.com/nature/journal/v419/n6910/full/nature01065.html">distinguish colours</a>, <a href="http://bit.ly/2mi1XqU">detect faint movements</a>, learn visual landmarks and <a href="http://bit.ly/2miaSIF">use them for homing</a>. They can even orient themselves using the faint celestial polarisation pattern <a href="http://www.nature.com/nature/journal/v424/n6944/full/424033a.html">produced by the moon</a>, and navigate using the constellations of <a href="http://bit.ly/2nvmNUu">stars in the sky</a>.</p>
<p>In many cases, this visual performance seems almost to defy what’s physically possible. For example, the nocturnal Central American sweat bee, <em>Megalopta genalis</em>, absorbs just five photons (light particles) into its tiny eyes when light levels are at their lowest – a <a href="http://bit.ly/2miaSIF">vanishingly small visual signal</a>. And yet, in the dead of night, it can navigate the dense and tangled rainforest on a foraging trip and make it safely back to its nest – an inconspicuous hollowed-out stick suspended within the forest understorey.</p>
<p>To find out how this kind of performance is possible, we recently began to study nocturnal hawkmoths. These beautiful insects –- the hummingbirds of the invertebrate world –- are sleek, fast-flying moths that are constantly on the lookout for nectar-laden flowers. Once a flower is found, the moth hovers in front of it, sucking the nectar out using its proboscis, a mouth-like tube.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/160495/original/image-20170313-19263-1u8f9id.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/160495/original/image-20170313-19263-1u8f9id.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/160495/original/image-20170313-19263-1u8f9id.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/160495/original/image-20170313-19263-1u8f9id.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/160495/original/image-20170313-19263-1u8f9id.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/160495/original/image-20170313-19263-1u8f9id.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/160495/original/image-20170313-19263-1u8f9id.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"><em>Deilephila elpenor</em>.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>The nocturnal European Elephant hawkmoth, <em>Deilephila elpenor</em>, is a gorgeous creature cloaked in feathery pink and green scales and does all its nectar gathering in the dead of night. A number of years ago we discovered that this moth can distinguish colours at night, the first nocturnal animal <a href="http://www.nature.com/nature/journal/v419/n6910/full/nature01065.html">known to do so</a>.</p>
<p>But this moth recently revealed another of its secrets: the neural tricks it uses to see well in extremely dim light. These tricks are certainly used by other nocturnal insects like <em>Megalopta</em>. By studying the physiology of neural circuits in the visual centres of the brain, we discovered that <em>Deilephila</em> can see reliably in dim light by effectively adding together the photons it has collected from different points <a href="http://bit.ly/2mi1XqU">in space and time</a>.</p>
<p>For time, this is a little like increasing the shutter time on a camera in dim light. By allowing the shutter to stay open longer, more light reaches the image sensor and a brighter image is produced. The downside is that anything moving rapidly – like a passing car – will not be resolved and so the insect won’t be able to see it.</p>
<h2>Neural summation</h2>
<p>To add together photons in space, the individual pixels of the image sensor can be pooled together to create fewer but larger (and so more light-sensitive) “super pixels”. Again, the downside of this strategy is that even though the image becomes brighter, it also becomes blurrier and finer spatial details disappear. But for a nocturnal animal straining to see in the dark, the ability to see a brighter world that is coarser and slower is likely to be better than seeing nothing at all (which would be the only alternative).</p>
<p>Our physiological work has revealed that this neural summation of photons in time and space is immensely beneficial to nocturnal <em>Deilephila</em>. At all nocturnal light intensities, from dusk to starlight levels, summation substantially boosts <em>Deilephila</em>’s ability to see well in dim light. In fact, thanks to these neural mechanisms, <em>Deilephila</em> can see at light intensities around 100 times dimmer than it could otherwise. The benefits of summation are so great that other nocturnal insects, like <em>Megalopta</em>, very likely rely on it to see well in dim light as well.</p>
<p>The world seen by nocturnal insects may not be as sharp or as well resolved in time as that experienced by their day-active relatives. But summation ensures that it is bright enough to detect and intercept potential mates, to pursue and capture prey, to navigate to and from a nest and to negotiate obstacles during flight. Without this ability it would be as blind as the rest of us.</p><img src="https://counter.theconversation.com/content/74101/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Eric Warrant receives funding from the Swedish Research Council (VR), the European Research Council (ERC), the Air Force Office of Scientific Research (ERC), the Wallenberg Foundation and the Royal Physiographic Society. He is a Fellow of the Royal Danish Academy of Sciences and Letters, Fellow and Board Member of the Royal Physiographic Society, Member and President Elect of the International Society of Neuroethology, Chairman of the Organismic Biology Panel of the Swedish Research Council and Vice Chair of the National Committee for Biology at the Royal Swedish Academy of Sciences.</span></em></p>Nocturnal insects have eyes that act like cameras to enhance their light-gathering abilities.Eric Warrant, Professor of Zoology, Lund UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/313492014-09-07T20:38:23Z2014-09-07T20:38:23ZLooking at the future through graphene goggles<figure><img src="https://images.theconversation.com/files/58321/original/ssh2tm4k-1409897403.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">There's definitely room for improvement in night-vision goggle technology – and graphene could make a huge contribution.</span> <span class="attribution"><a class="source" href="http://www.flickr.com/photos/defenceimages/9241716090">UK Ministry of Defence/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p><a href="https://theconversation.com/from-pencil-to-high-speed-internet-graphene-is-a-modern-wonder-3146">Graphene</a> – an atom-thick sheet of carbon – has been touted as a new wonder material: it is stronger than steel and conducts electricity better than copper. </p>
<p>In the journal <a href="http://www.nature.com/nnano/index.html">Nature Nanotechnology</a> today, my colleagues and I show how graphene can be used to build a detector of long wavelength (far infrared or <a href="http://en.wikipedia.org/wiki/Terahertz_radiation">terahertz</a>) light that is as sensitive as any existing detector, but far smaller and more than a million times faster. The detector could improve night-vision goggles, chemical analysis tools and airport body scanners.</p>
<p>But before I go into the research, I’d like to talk about how we get from the discovery of a new wonder material such as graphene to new technologies that are useful. </p>
<p>As a researcher working on new materials, I am constantly asked “what is it good for?” To answer this, the first thing we researchers often try is to imagine the new material as a replacement for an existing one in an existing technology. </p>
<p>The problem with that approach is that any existing technology has a lot of momentum. For example, consider computer processors. The electrons in graphene move about 70 times faster than those in silicon (used in most computer processors today) under the same conditions, so graphene could arguably be used to make faster computer chips. </p>
<p>But it’s not that simple. There are many reasons we use silicon besides the speed at which electrons travel – it readily forms a strong oxide coating and it is easy to <a href="http://electronics.howstuffworks.com/diode1.htm">dope</a>, to name a couple. And changing to a radically different material would mean throwing away all the infrastructure used to make silicon chips that was developed at enormous expense over the past several decades.</p>
<p>So a better question — though much more difficult to answer — is to ask what a new material might enable us to do that no other material has before. The answers to that question don’t always come immediately, and sometimes they come serendipitously.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/6cmZ2IGacsQ?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">A walk-through of some of the research in the Fuhrer laboratory: created by Anna Grieve, Big Stories Co.</span></figcaption>
</figure>
<h2>Two layers are better than one</h2>
<p>One property of graphene that interested me was that bilayer graphene (two layers stacked one on another) has a bandgap — the basic property of a semiconductor — that can be tuned by applying an electric field to the material.</p>
<p>I teamed up with researchers at the University of Maryland to try to measure this bandgap using infrared light, since infrared photons have energies which are similar to bilayer graphene’s bandgap. When we measured the conductance of our bilayer graphene under infrared illumination, we found that it changed much more than we expected. </p>
<p>In fact, the change in conductance in our graphene was greater than that of the commercial silicon photodetector we were using to measure the power of our infrared beam! For some reason, our graphene was an excellent photodetector. </p>
<p>We knew enough about graphene to figure out what was happening. When the electrons in graphene absorb light, they heat up. In most materials, the electrons quickly lose energy to vibrations of the atoms, which we sense as heat. </p>
<p>But in graphene this process of heat loss is very inefficient, which gives graphene its extraordinarily high electrical conductivity. What we realised is that bilayer graphene with a bandgap has a conductance that varies strongly with electron temperature, allowing us to read out the change in electron temperature caused by the light heating the electrons. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/58322/original/gr9mcq95-1409897608.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/58322/original/gr9mcq95-1409897608.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/58322/original/gr9mcq95-1409897608.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=210&fit=crop&dpr=1 600w, https://images.theconversation.com/files/58322/original/gr9mcq95-1409897608.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=210&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/58322/original/gr9mcq95-1409897608.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=210&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/58322/original/gr9mcq95-1409897608.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=264&fit=crop&dpr=1 754w, https://images.theconversation.com/files/58322/original/gr9mcq95-1409897608.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=264&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/58322/original/gr9mcq95-1409897608.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=264&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A graphene photothermoelectric detector. The active area of the device is a 0.5 mm by 0.5 mm square which consists of strips of graphene contacted by partially overlapping gold and chromium electrodes.</span>
<span class="attribution"><span class="source">Michael Fuhrer</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Such a device is called a “hot electron bolometer” and bilayer graphene makes a very good one. We <a href="http://www.nature.com/nnano/journal/v7/n7/full/nnano.2012.88.html">published our result</a> in the journal Nature Nanotechnology in 2012, and several research groups are interested in developing graphene bolometers as exquisitely sensitive cryogenic detectors for use in radio astronomy.</p>
<p>Unfortunately, the bolometric effect only works well at low temperature, where bilayer graphene’s resistance changes strongly with temperature. But we knew from our measurements that hot electron effects should be important in graphene at room temperature. </p>
<p>Our team designed a device which could measure the hot electrons at room temperature, using an effect called thermoelectricity. Our first graphene photothermoelectric detectors were comparable in sensitivity to the best available room-temperature detectors of light in the far infrared, or terahertz, regime of the electromagnetic spectrum, and we saw room for orders of magnitude improvements in sensitivity with new designs. </p>
<p>Interestingly, our devices were more than a million times faster than those detectors, and it’s these results we publish today, once again in Nature Nanotechnology.</p>
<h2>Graphene shows us the light</h2>
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<a href="https://images.theconversation.com/files/58324/original/4t3yfn3c-1409898948.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/58324/original/4t3yfn3c-1409898948.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/58324/original/4t3yfn3c-1409898948.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/58324/original/4t3yfn3c-1409898948.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/58324/original/4t3yfn3c-1409898948.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/58324/original/4t3yfn3c-1409898948.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/58324/original/4t3yfn3c-1409898948.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/58324/original/4t3yfn3c-1409898948.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1005&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption"></span>
<span class="attribution"><a class="source" href="http://www.flickr.com/photos/plushplex/5267461232/in/photostream/">plushplex/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
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<p>Detection of infrared and terahertz light has numerous uses, from chemical analysis to night-vision goggles to body scanners used in airport security. </p>
<p>But since an ultra-fast, sensitive terahertz detector had never been considered a possibility before, it’s hard to say where our devices might be applied. </p>
<p>Our detector could be used to speed up chemical analysis techniques such as Fourier transform infrared spectroscopy, or <a href="http://chemwiki.ucdavis.edu/Physical_Chemistry/Spectroscopy/Vibrational_Spectroscopy/Infrared_Spectroscopy/How_an_FTIR_Spectrometer_Operates">FTIR</a>. </p>
<p>Because the graphene detector is easily microfabricated, we envision arrays of detector pixels suitable for imaging, which could lead to inexpensive infrared cameras or night-vision goggles.</p>
<p>Our calculations show that the hot electron photothermoelectric effect can be an efficient means of gathering energy from light. Perhaps our devices could be used to gather the infrared light escaping the Earth into the night sky, and turn it into electricity. Maybe they will be used for something that we haven’t even thought of yet. </p>
<p>But had we never set out to investigate a new material simply for the sake of understanding how it works, we never would have discovered these new answers to the question, “what is it good for?”</p><img src="https://counter.theconversation.com/content/31349/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Michael Fuhrer receives funding from the Australian Research Council, U.S. National Science Foundation, U.S. Office of Naval Research, and U.S. Intelligence Advanced Research Projects Activity.</span></em></p>Graphene – an atom-thick sheet of carbon – has been touted as a new wonder material: it is stronger than steel and conducts electricity better than copper. In the journal Nature Nanotechnology today, my…Michael Fuhrer, Professor of Physics, Monash UniversityLicensed as Creative Commons – attribution, no derivatives.