Tunable quantum cascade laser

first_img Copyright 2010 PhysOrg.com. All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of PhysOrg.com. More information: Kazuue Fujita, Tadataka Edamura, Shinichi Furuta, and Masamichi Yamanishi, “High-performance, homogenous broad-gain quantum cascade lasers based on dual-upper-state design,” Applied Physics Letters (2010). Available online: link.aip.org/link/APPLAB/v96/i24/p241107/s1 Explore further (PhysOrg.com) — One of the issues associated with lasers is their tunability. In many cases, if you want to produce a particular wavelength, you have to build a laser to accomplish this. In order to get another wavelength, you may have to build a different laser. A tunable laser would provide an opportunity to adjust the wavelength, without the use of another laser. One novel quantum cascade laser design that could achieve this is based on a dual upper state design. Citation: Tunable quantum cascade laser (2010, July 7) retrieved 18 August 2019 from https://phys.org/news/2010-07-tunable-quantum-cascade-laser.htmlcenter_img A team at the Central Research Laboratory at Hamamatsu Photonics K.K. in Japan has come up with, and tested, a tunable quantum cascade laser design that demonstrates broad optical gain. Their work is published in Applied Physics Letters: “High-performance, homogenous broad-gain quantum cascade lasers based on dual-upper-state design.”“Usually, quantum cascade laser designs have only one upper state, except for superlattice active region,” Kazuue Fujita, the lead author on the paper, tells PhysOrg.com in an email interview. In this case, though, there is an additional upper state added to the design of the laser. “The additional upper state is created by a first quantum well adjacent to the injection barrier. This state corresponds to a lowest energy state in the first quantum well.”Fujita goes on to explain that the regular upper state, seen in most conventional quantum cascade lasers, is designed to be nearly the same energy at operating condition as the state in the first quantum well. “Electrons are injected into the higher upper state via resonant tunneling from the previous injector. And then, electrons populated in the both upper states transit from both upper states to a lower state.” Both of these transitions contribute to optical gain.This new laser design would have a number of advantages over current quantum cascade laser designs insists Fujita. This laser design allows for broadband tuning. On top of that, there is weak dependence on voltage by these lasers, and they are not sensitive to temperature change. “Slow efficiency at threshold is observed to be nearly constant over the wide range. Also I-L characteristics show super-linear behavior. These distinctive features have never been observed in a quantum cascade laser so far,” Fujita explains. “I think this design concept holds large potentialities.”Fujita says that the design has actually been tested. “We have already fabricated and measured many lasers with the design. The lasers demonstrate very good performances. In addition, high temperature, continuous wave operation of the laser has also been achieved.”In terms of application, Fujita sees a great deal of usefulness, especially in terms of spectroscopy. Trace gas sensing is considered one of the more likely applications, since wide tunability is desired. “The external cavity quantum cascade laser with this design may operate very stable due to its low dependences on voltage and temperature,” he says. Due to its tunability, this quantum cascade laser design could also increase the cost efficiency of some applications. “This design can lead to high-performance broadband tuning. Therefore, the laser allows a reduction in the number of lasers in a spectroscopic analysis system.” Compact, wavelength-on-demand Quantum Cascade Laser chip created This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.last_img read more

Selfinflating bike tires campaign for dollars

first_imgPumpTire developers have in mind two end products, one for casual cyclists and the other for cyclists who want high performance. For the latter, The City Pro has a max 100 psi, and the City Cruiser is a 26″ x 1.5″ tire with a maximum 65 psi.In the video showing how it works, the founder of the project, Benjamin Krempel, hops on his bicycle and takes it for a ride. We see the pressure on the tire rising from 22 to 52 psi in over a mile. As for the higher-performance tire product, the user is allowed to set the pressure from 65 to 95 psi.True to the Kickstarter project practice, Krempel and team are posting project details on the Kickstarter site, hoping backers will donate toward their goal, which is $250,000. They want to use that money to work with vendors and engineers to put in place the right materials and processes and to get tools and materials for assembly. The project will only be funded if at least $250,000 is pledged by October 5, according to the site. At the time of this writing, they have $3,619 with 43 backers. As offers to those who pledge, they give those who pledge $75 two Cruiser tires, two valves and two tubes at the expected retail value of $129.90. Those who pledge $45 get one Cruiser tire, (you guessed it). one valve and one tube at the expected retail price of $64.95. Pledges of one dollar or more get the team’s warm thanks for doing a good deed. Explore further (PhysOrg.com) — Bicycle owners are being offered a no-hassle solution to keeping their bicycle tires sidewalk and road-worthy. The solution is called the PumpTire, billed as the world’s first self-inflating bicycle tire. Thanks simply to the rolling motion of the tire, and inventor ingenuity, it can happen. Right now, it’s an advanced prototype, not something to yank off any shelf. PumpTire is promoting this off the Kickstarter project site. The PumpTire team hopes that, with enough donations, they can transform their prototype into products for cyclists everywhere. Citation: Self-inflating bike tires campaign for dollars (2011, August 26) retrieved 18 August 2019 from https://phys.org/news/2011-08-self-inflating-bike-campaign-dollars.html © 2011 PhysOrg.com PumpTire is the company and product name of a set of items that consist of a tire, a tube, and detachable valve. The inner tube clips into the tire to allow the air to pass from the tire to the tube. Once the desired pressure is reached, the pump stops. The valve senses the increase in pressure. and closes the air pathway so that no more air is pumped into the tire. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. PumpTire prototype takes riders off of pumping grind More information: www.kickstarter.com/projects/8 … flating-bicycle-tirelast_img read more

Uhoh Intel Globalfoundries to fastforward into 14nm

first_img Citation: Uh-oh, Intel. Globalfoundries to fast-forward into 14nm (2012, September 24) retrieved 18 August 2019 from https://phys.org/news/2012-09-uh-oh-intel-globalfoundries-fast-forward-14nm.html © 2012 Phys.org This is a nonplanar architecture optimized for low-power, mobile system-on-chip (SoC) designs. These chips will deliver a 40 percent to 60 percent improvement in battery life compared to two-dimension planar transistors at the 20nm node. Globalfoundries will go “3-D” in the use of three-dimensional “FinFET” transistors. The big deal about “FinFET” rests in its promoted superior low-power attributes. The FinFET architecture takes a traditional two-dimensional transistor design and turns the conductive channel on its side, resulting in a three-dimensional fin structure, surrounded by a gate controlling the flow of current. The 3-D transistor design operates at a lower voltage with minimal current leakage. This leads to a longer battery life for mobile applications and less power consumption for plugged-in applications. The power-consumption advantage could have important implications for networking chips in data centers.Intel’s challenge is not only in the rival company’s technology but also in 14nm timelines. Globalfoundries is speeding up its timeline for its 14nm process. Chip watchers note that in so doing it is playing leapfrog over other companies. The company will be ready to roll with a 14-nanometer process that will include its three-dimensional transistor architecture. This is said to be similar to Intel’s Tri-Gate method. Enthusiasts say that the 14nm-XM design is expected to carry performance and power benefits of three-dimensional FinFET transistors, possibly influencing a newer generation of mobile devices.With the Globalfoundries plan, chip designers will be able to start producing sample 14 nanometer chips in 2013. In 2014 or early 2015, the 14 nm chips will be part of the consumer marketplace. Technology development of the 14nm-XM has begun in Globalfoundries’ Fab 8, a fabrication plant in Saratoga County, New York. The company is making early process design kits (PDKs) which are available now. Customer tape-outs—the final result of the design—are expected in 2013. Globalfoundries was formerly a manufacturing arm of AMD. Headquartered in Milpitas, California, Globalfoundries now counts itself as one of the largest foundries in the world by revenue. Imec releases industry’s first 14nm process development kit More information: www.globalfoundries.com/technology/14XM.aspx Explore further (Phys.org)—Globalfoundries has made an announcement that amounts to a direct challenge to Intel, in the latter’s race to get further ahead in the mobile device ecosystem. Both Globalfoundries and Intel will be racing for a more dominant position with higher performing and power efficient systems for smartphones and other devices. In short, Globalfoundries announced Thursday that it is accelerating its technology roadmap. Its newest design achievement for the mobile market is in the form of 14nm chip technology. The company provided some details about its 14nm-XM (“extreme mobility”) process. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.last_img read more

Researchers investigate stellar populations in the central region of the Andromeda galaxy

first_imgThe Andromeda galaxy. Credit: Adam Evans. German astronomers have conducted a study of the central bulge of the Andromeda galaxy and analyzed its stellar populations. The research could improve our understanding of the bulge’s structure and formation history. Results of the study are presented in a paper published July 24 on the arXiv pre-print repository. More information: The stellar populations of the central region of M31, arXiv:1807.09284 [astro-ph.GA] arxiv.org/abs/1807.09284AbstractWe continue the analysis of the dataset of our spectroscopic observation campaign of M31, by deriving simple stellar population properties (age metallicity and alpha-elements overabundance) from the measurement of Lick/IDS absorption line indices. We describe their two-dimensional maps taking into account the dust distribution in M31. 80% of the values of our age measurements are larger than 10 Gyr. The central 100 arcsec of M31 are dominated by the stars of the classical bulge of M31. They are old (11-13 Gyr), metal-rich (as high as [Z/H]~0.35 dex) at the center with a negative gradient outwards and enhanced in alpha-elements ([alpha/Fe]~ 0.28+- 0.01 dex). The bar stands out in the metallicity map, where an almost solar value of [Z/H] (~0.02+-0.01 dex) with no gradient is observed along the bar position angle (55.7 deg) out to 600 arcsec from the center. In contrast, no signature of the bar is seen in the age and [alpha/Fe] maps, that are approximately axisymmetric, delivering a mean age and overabundance for the bar and the boxy-peanut bulge of 10-13 Gyr and 0.25-0.27 dex, respectively. The boxy/peanut-bulge has almost solar metallicity (-0.04+- 0.01 dex). The mass-to-light ratio of the three components is approximately constant at M/LV ~ 4.4-4.7 Msol/Lsol. The disk component at larger distances is made of a mixture of stars, as young as 3-4 Gyr, with solar metallicity and smaller M/LV (~3+-0.1 Msol/Lsol). We propose a two-phase formation scenario for the inner region of M31, where most of the stars of the classical bulge come into place together with a proto-disk, where a bar develops and quickly transforms it into a boxy-peanut bulge. Star formation continues in the bulge region, producing stars younger than 10 Gyr, in particular along the bar, enhancing its metallicity. The disk component appears to build up on longer time-scales. Groundbreaking study sheds new light on galaxy evolution © 2018 Phys.org Located some 2.5 million light years away from the Earth, the barred spiral Andromeda galaxy, also known as Messier 31, or M31 for short, is the nearest major galaxy to the Milky Way. Due to its proximity, M31 is an excellent target to study the detailed evolutionary history of large spiral galaxies.Andromeda’s central bulge is crucial for such studies, so recently, a team of researchers from Germany led by Roberto Philip Saglia of the Max Planck Institute for Extraterrestrial Physics in Garching, decided to analyze the stellar populations of this region in detail.For their research, the team used the 2.7 meter telescope at the McDonald Observatory in Texas to obtain spectroscopic data of M31. The observational campaign allowed the astronomers to uncover simple stellar population properties of the central region of this galaxy, including age, metallicity and alpha-elements abundance.”We observed M31 for 14 nights with the integral-field spectrograph VIRUS-W attached to the 2.7m telescope at the McDonald Observatory, Texas, covering the bulge area with a filling factor of 1/3 and sampling the disk along six different directions, reaching approximately one scalelength along the major axis,” the scientists wrote in the paper.According to the study, the stellar populations in the central region of M31 are fairly old—more than 10 billion years old. In comparison, the stars of the galaxy’s disk are younger by 5 to 6 billion years.In particular, the researchers found that the central 100 arcsec of this galaxy is dominated by old, metal-rich stars at the center with a negative gradient outwards and enhanced in alpha elements.The study reveals that M31’s bulge as well as bar have solar metallicities. The team also found that the bar and bulge have a mean age of 10 and 13 billion years respectively.The authors of the paper concluded that their result suggest a two-phase formation scenario for the inner region of M31.”A classical stellar bulge forms together with a primordial disk, from a quasi-monolithic collapse or violent instability of the turbulent inner proto-disk. On larger scales, the proto-disk develops a bar. The bar buckles and transforms the proto-disk into the boxy-peanut B/P bulge. The stars in this region are mainly old,” the researchers concluded.The team plans further studies of M31 that might shed further light on the sequence of events that built the central regions of this galaxy. Moreover, they will try to calculate the rate of microlensing events expected from the self-lensing of the different populations of the central region of the Andromeda galaxy. Explore further This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Citation: Researchers investigate stellar populations in the central region of the Andromeda galaxy (2018, August 6) retrieved 18 August 2019 from https://phys.org/news/2018-08-stellar-populations-central-region-andromeda.htmllast_img read more

Lets pimp the disco

first_imgTell us a bit about yourselves and how did you guys come together as a band?We’ve both been individual musicians for awhile now prior to this collaboration. Saba has been singing with a bunch of other bands as well as working as a professional sessions vocalist and playback singer, and Imaad is the frontman/ guitarist for The Pulp Society, as well as produces solo under the moniker Madboy. Imaad heard Saba’s voice at a late night jam with some friends and immediately knew he had to get her to sing on some of his productions. Also Read – ‘Playing Jojo was emotionally exhausting’And how did the name come about?It’s basically a combination of two solo projects. Madboy is Imaad’s project as a solo producer and Mink is Saba’s moniker as a producer and DJ. So we just thought combining the two would be simple and non-pretentious. Tell us about what drives you guys, what are your influences?Our personal influences are extremely varied and diverse but for this project we are focusing on a sound which is driven by old style Harlem swing and bringing that into context with production that’s rooted in disco and funk. It’s our own trademark sound and it’s hard to explain too much- it’s something that needs to be experienced. Also Read – Leslie doing new comedy special with NetflixTell us a bit about the songs you have planned for this chapter at Raasta?We haven’t been releasing too much of our material online, because we like each of our releases to be really special and when the EP is released, It’s going to be pretty hyped. But in spite of that, a lot of our tunes have been spreading by word of mouth and gigs that have travelled all over the place. Our songs – Pimp the Disco, Taste your kiss, Lemonade (which was our first single release and is on Soundcloud) Trouble, Soulboy etc and many more will all be on the set list. What’s next in the pipeline for you guys?We play Sunburn in Goa which is the last gig for the year for us coming at the end of our first year as ‘Madboy/Mink’ and it’s been a very busy year in terms of gigs. We’re just going to take stock, lock ourselves in the studio for a little while, and complete the final mixes for our EP which will be out most probably by the end of Feb or beginning of March – and will be followed by a comprehensive tour across the country.WHEN: 25 December, 9 pm onwardsWHERE: Raasta, Hauz Khas Villagelast_img read more

Knots and stitches

first_imgThe 29th edition of India Carpet Expo showcases more than 275 reputed manufacturer exporters from all over country like – U.P., Rajasthan, Haryana, Jammu and Kashmir, Punjab, Madhya Pradesh, Himachal Pradesh, Andhra Pradesh etc. A record number of 450 overseas carpet buyers from around 57 countries mainly USA, Germany, France, UK, Turkey, Brazil, China, Canada, Denmark, Japan, Korea, European Union Countries etc shall be visiting the expo to generate business for this rural based cottage sector. Also Read – ‘Playing Jojo was emotionally exhausting’The event is organised by Carpet Export Promotion Council of India (CEPC) setup by Ministry of Textiles government o?f India. CEPC was established to promote the exports of hand-made / hand-knotted carpets and other floor coverings. CEPC therefore, helps in skill enhancement of weavers, artisans, entrepreneurs, strengthening base in existing markets, identifying potential markets, educating about government policies and its compliances, providing financial assistance for brand building of Indian hand-made carpets, through publicity, participating in world renowned trade fairs and expositions.Where: Hall no. 8- 11, Pragati MaidanWhen: March 27 – 30last_img read more

15 dead 10 injured in road accident in AP

first_imgAt least 15 people, including three children, were killed on Saturday and 21 injured when a mini truck carrying a marriage party collided with a bus near Kandukur town in Prakasam district of Andhra Pradesh.Police said a mini truck carrying a marriage party coming from Kandukur hit the bus coming from the opposite direction.Fifteen people have been killed in the mishap after the bus caught fire in the mishap, Inspector of Police (Kandukur) M Lakshman said. Also Read – Punjab on alert after release of excess water from Bhakra damThe mini truck was carrying 40 passengers while there were no passengers on board in the bus. Fire tenders were pressed into service to douse the flames.The officer said the injured are being shifted to Kandukur, Ongole and Nellore districts for treatment. Andhra Pradesh transport minister Sidda Raghava Rao also reached the spot and is supervising the rescue operations.District Collector Sujatha Sarma also visited the mishap site.The deceased were identified as — N Subhasini (31), P Prasad (30), R Subba Rao (50), E Chiranjeevi (45), S Chandu (10), S Adinarayana (10), Srilakha (8), M Padma (40), K Sushela (47), S Venkateswara Rao (40), S Rajamma (40), V Subbaiah (30), V Chinnaya, S Rajayya, and B Hazarataiah.last_img read more

Live better with strawberries

first_imgStrawberries or garden strawberry, commonly known as Fragaria ananassa an edible fruit which is a hybrid species of French and Argentinean varieties, is cultivated across the globe. The fruit is juicy and hence keeps your body rehydrated during summers. Also, it is very useful for cognitive development and gives you a strong vision. 1.Vitamin C in strawberries strengthens the immunity system of the body. The content of vitamin C fights against cough, cold, flu and viral infections. Strawberries contain antioxidants which allow proper functioning of the cells in the body. Vitamin C, itself being an antioxidant, prevents inflammation and free radicals. Also Read – Add new books to your shelf 2. Strawberry consists of an element called alpha-hydroxy acid which acts as a natural scrubber. Thus it can be used as a scrubber to remove the dead skin cells. Also, aspartic acid in strawberry removes the toxins from the skin. So experience complete rejuvenation and get the naturally embraceable glowing skin with strawberries to feel that touch! 3. Blessed with antioxidants, flavonoids, fibre, potassium, vitamin C and folate, strawberry is a great fruit to successfully fight against a variety of heart ailments. These essential nutrients help to lower the levels of bad cholesterol in the body. Flavonoids help to regulate the proper functioning of arteries and prevent blood clotting even. Vitamin C is effective in making the heart muscles strong and efficient. Potassium and magnesium reduce the risk of high blood pressure. So, all the heart patients will surely embrace strawberries with joy!last_img read more

Bhangar project Construction suspended after inconclusive meeting

first_imgKolkata: The construction work for installing a tower at the power grid project in Bhangar has been suspended as the meeting held between the local people and the district administration officials on Friday failed to arrive at a consensual decision.Another meeting would take place on 31 December in this regard. The local residents and the members of the Jami Jibika Bastutantra O Paribesh Rakshya Committee (JJBPRC) refused to allow the construction of the tower unless their demands are met by the district administration. Also Read – Rain batters Kolkata, cripples normal lifeThe meeting was held for nearly five hours on Friday morning but the issue was not resolved. The members of the JJBPRC staged a demonstration at the project site on Thursday, stalling the construction work of the tower. Some of the villagers and committee members alleged that other development projects which were promised by the government earlier have been stalled as well and hence they would not allow the power project to continue. JJBPRC members also alleged that the local administration had assured them that dredging of river would take place and a hospital would be set up but no steps have been taken so far. Also Read – Speeding Jaguar crashes into Mercedes car in Kolkata, 2 pedestrians killedThey also alleged that the district administration had agreed to meet certain demands of them, including the introduction of vocational training for the unemployed youths in the area and also setting up of a cold storage for fishermen and farmers. But nothing has happened, they said. It may be mentioned here that a logjam had been created in the power grid project in Bhangar for sometime as they local people did not want the project to take place. The matter was finally resolved following the intervention of the Power department and administration officials in the district. Chief Minister Mamata Banerjee, during her administrative meeting in the district on Thursday, expressed her dissatisfaction over the non-completion of the power grid project and sought an explanation from the Power department officials as to why the project has not been completed despite the efforts made by the state government in this regard.last_img read more

Sleep well to avoid eating junk food due to job stress

first_imgStress at your job can lead to overeating and intake of junk food at dinnertime, but there could be a buffer to this harmful pattern. New research suggests that a good night’s sleep can serve as a protecting factor between job stress and unhealthy eating in the evening.”We found that employees who have a stressful workday tend to bring their negative feelings from the workplace to the dinner table, as manifested in eating more than usual and opting for more junk food instead of healthy food,” said study co-author Chu-Hsiang Chang, Associate Professor of Psychology at Michigan State University in the US. Also Read – Add new books to your shelfThe research, published online in the Journal of Applied Psychology, involved two studies of 235 workers in China. One study dealt with information technology employees who regularly experienced high workload and felt there was never enough time in the workday. The second study involved call-centre workers who often got stressed from having to deal with rude and demanding customers.In both cases, workday stress was linked to employees’ negative mood while on the job, which in turn was linked to unhealthy eating in the evening, study co-author Yihao Liu, Assistant Professor at the University of Illinois, said. Also Read – Over 2 hours screen time daily will make your kids impulsiveThe study proposed two potential explanations, Liu said.”First, eating is sometimes used as an activity to relieve and regulate one’s negative mood, because individuals instinctively avoid aversive feelings and approach desire feelings,” he said. “Second, unhealthy eating can also be a consequence of diminished self-control. When feeling stressed out by work, individuals usually experience inadequacy in exerting effective control over their cognitions and behaviours to be aligned with personal goals and social norms,” Liu added.The finding that sleep protects against unhealthy eating following workday stress shows how the health behaviours are related, Chang pointed out.”A good night’s sleep can make workers replenished and feel vigorous again, which may make them better able to deal with stress at work the next day and less vulnerable to unhealthy eating,” she said.last_img read more