World"s most powerful terahertz laser chip

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University of Leeds researchers have taken the lead in the race to build the world’s most powerful terahertz laser chip.A paper in the Institution of Engineering and Technology’s (IET) journal Electronics Letters reports that the Leeds team has exceeded a 1 Watt output power from a quantum cascade terahertz laser.The new record more than doubles landmarks set by the Massachusetts Institute of Technology (MIT) and subsequently by a team from Vienna last year.Terahertz waves, which lie in the part of the electromagnetic spectrum between infrared and microwaves, can penetrate materials that block visible light and have a wide range of possible uses including chemical analysis, security scanning, medical imaging, and telecommunications.Widely publicised potential applications include monitoring pharmaceutical products, the remote sensing of chemical signatures of explosives in unopened envelopes, and the non-invasive detection of cancers in the human body.However, one of the main challenges for scientists and engineers is making the lasers powerful and compact enough to be useful.Professor Edmund Linfield, Professor of Terahertz Electronics in the University’s School of Electronic and Electrical Engineering, said: “Although it is possible to build large instruments that generate powerful beams of terahertz radiation, these instruments are only useful for a limited set of applications. We need terahertz lasers that not only offer high power but are also portable and low cost.”The quantum cascade terahertz lasers being developed by Leeds are only a few square millimetres in size.In October 2013, Vienna University of Technology announced that its researchers had smashed the world record output power for quantum cascade terahertz lasers previously held by Massachusetts Institute of Technology (MIT). The Austrian team reported an output of 0.47 Watt from a single laser facet, nearly double the output power reported by the MIT team. The Leeds group has now achieved an output of more than 1 Watt from a single laser facet.Professor Linfield said: “The process of making these lasers is extraordinarily delicate. Layers of different semiconductors such as gallium arsenide are built up one atomic monolayer at a time. We control the thickness and composition of each individual layer very accurately and build up a semiconductor material of between typically 1,000 and 2,000 layers. The record power of our new laser is due to the expertise that we have developed at Leeds in fabricating these layered semiconductors, together with our ability to engineer these materials subsequently into suitable and powerful laser devices.”Professor Giles Davies, Professor of Electronic and Photonic Engineering in the School of Electronic and Electrical Engineering, said: “The University of Leeds has been an international leader in terahertz engineering for many years. This work is a key step toward increasing the power of these lasers while keeping them compact and affordable enough to deliver the range of applications promised by terahertz technology.”This work was mainly funded by the Engineering and Physical Sciences Research Council (EPSRC).Story Source:The above story is based on materials provided by University of Leeds. Note: Materials may be edited for content and length.


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Four unknown galaxy clusters containing thousands of galaxies discovered 10 billion light years from Earth

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Four unknown galaxy clusters each potentially containing thousands of individual galaxies have been discovered some 10 billion light years from Earth.An international team of astronomers, led by Imperial College London, used a new way of combining data from the two European Space Agency satellites, Planck and Herschel, to identify more distant galaxy clusters than has previously been possible. The researchers believe up to 2000 further clusters could be identified using this technique, helping to build a more detailed timeline of how clusters are formed.Galaxy clusters are the most massive objects in the universe, containing hundreds to thousands of galaxies, bound together by gravity. While astronomers have identified many nearby clusters, they need to go further back in time to understand how these structures are formed. This means finding clusters at greater distances from Earth.The light from the most distant of the four new clusters identified by the team has taken over 10 billion years to reach us. This means the researchers are seeing what the cluster looked like when the universe was just three billion years old.Lead researcher Dr David Clements, from the Department of Physics at Imperial College London, explains: “Although we’re able to see individual galaxies that go further back in time, up to now, the most distant clusters found by astronomers date back to when the universe was 4.5 billion years old. This equates to around nine billion light years away. Our new approach has already found a cluster in existence much earlier than that, and we believe it has the potential to go even further.”The clusters can be identified at such distances because they contain galaxies in which huge amounts of dust and gas are being formed into stars. This process emits light that can be picked up by the satellite surveys.Galaxies are divided into two types: elliptical galaxies that have many stars, but little dust and gas; and spiral galaxies like our own, the Milky Way, which contain lots of dust and gas. Most clusters in the universe today are dominated by giant elliptical galaxies in which the dust and gas has already been formed into stars.”What we believe we are seeing in these distant clusters are giant elliptical galaxies in the process of being formed,” says Dr Clements.Observations were recorded by the Spectral and Photometric Imaging Receiver (SPIRE) instrument as part of Herschel Multi-tiered Extragalactic Survey (HerMES). Seb Oliver, Head of the HerMES survey said: “The fantastic thing about Herschel-SPIRE is that we are able to scan very large areas of the sky with sufficient sensitivity and image sharpness that we can find these rare and exotic things. …


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Genetic chip will help salmon farmers breed better fish

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Atlantic salmon production could be boosted by a new technology that will help select the best fish for breeding.The development will enable salmon breeders to improve the quality of their stock and its resistance to disease.A chip loaded with hundreds of thousands of pieces of DNA — each holding a fragment of the salmon’s genetic code — will allow breeders to detect fish with the best genes.It does so by detecting variations in the genetic code of each individual fish — known as single nucleotide polymorphisms (SNPs). These variations make it possible to identify genes that are linked to desirable physical traits, such as growth or resistance to problematic diseases, for example sea lice infestations.Salmon breeders will be able to carry out the test by taking a small sample of fin tissue.The chip carries over twenty times more genetic information than existing tools. Similar chips have already transformed breeding programmes for land-farmed livestock including cattle and pigs.Salmon farming contributes around half a billion pounds to the UK economy each year and provides healthy, high quality food. Worldwide, approximately 1.5 million tonnes of Atlantic salmon are produced every year.Scientists from the University of Edinburgh’s Roslin Institute and Edinburgh Genomics initiative developed the chip with researchers from the Universities of Stirling and Glasgow. They worked with industrial partners Affymetrix UK and Landcatch Natural Selection. The work was funded by the UK’s innovation agency — the Technology Strategy Board — and the Biotechnology and Biological Sciences Research Council.The chip is highlighted in a study published today in the journal BMC Genomics and it will be available to breeders and farmers from March 2014.Dr Ross Houston, of The Roslin Institute, said: “Selective breeding programmes have been used to improve salmon stocks since the 1970s. This new technology will allow the best breeding fish to be selected more efficiently and accurately, particularly those with characteristics that are difficult to measure such as resistance to disease”Dr Alan Tinch, director of genetics at Landcatch Natural Selection, said: “This development takes selective breeding programmes to a whole new level. It is an extension to the selective breeding of salmon allowing more accurate identification of the best fish to create healthier and more robust offspring.”Story Source:The above story is based on materials provided by University of Edinburgh. Note: Materials may be edited for content and length.


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Arctic biodiversity under serious threat from climate change

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Unique and irreplaceable Arctic wildlife and landscapes are crucially at risk due to global warming caused by human activities according to the Arctic Biodiversity Assessment (ABA), a new report prepared by 253 scientists from 15 countries under the auspices of the Conservation of Arctic Flora and Fauna (CAFF), the biodiversity working group of the Arctic Council.”An entire bio-climatic zone, the high Arctic, may disappear. Polar bears and the other highly adapted organisms cannot move further north, so they may go extinct. We risk losing several species forever,” says Hans Meltofte of Aarhus University, chief scientist of the report.From the iconic polar bear and elusive narwhal to the tiny Arctic flowers and lichens that paint the tundra in the summer months, the Arctic is home to a diversity of highly adapted animal, plant, fungal and microbial species. All told, there are more than 21,000 species.Maintaining biodiversity in the Arctic is important for many reasons. For Arctic peoples, biodiversity is a vital part of their material and spiritual existence. Arctic fisheries and tourism have global importance and represent immense economic value. Millions of Arctic birds and mammals that migrate and connect the Arctic to virtually all parts of the globe are also at risk from climate change in the Arctic as well as from development and hunting in temperate and tropical areas. Marine and terrestrial ecosystems such as vast areas of lowland tundra, wetlands, mountains, extensive shallow ocean shelves, millennia-old ice shelves and huge seabird cliffs are characteristic to the Arctic. These are now at stake, according to the report.”Climate change is by far the worst threat to Arctic biodiversity. Temperatures are expected to increase more in the Arctic compared to the global average, resulting in severe disruptions to Arctic biodiversity some of which are already visible,” warns Meltofte.A planetary increase of 2 C, the worldwide agreed upon acceptable limit of warming, is projected to result in vastly more heating in the Arctic with anticipated temperature increases of 2.8-7.8 C this century. …


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