文章来源:未知 文章作者:meng 发布时间:2010-12-21 02:21 字体: [ ]  进入论坛

Researchers at the University of California, Berkeley, have developed a new technique that allows plasmon(胞质基因,等离子体振子) lasers to operate at room temperature, overcoming a major barrier to practical utilization1 of the technology. The achievement, described Dec. 19 in an advanced online publication of the journal Nature Materials, is a "major step towards applications" for plasmon lasers, said the research team's principal investigator2, Xiang Zhang, UC Berkeley professor of mechanical engineering and faculty3 scientist at Lawrence Berkeley National Laboratory.

"Plasmon lasers can make possible single-molecule4 biodetectors, photonic(光激性的) circuits and high-speed optical communication systems, but for that to become reality, we needed to find a way to operate them at room temperature," said Zhang, who also directs at UC Berkeley the Center for Scalable and Integrated Nanomanufacturing, established through the National Science Foundation's (NSF) Nano-scale Science and Engineering Centers program.

In recent years, scientists have turned to plasmon lasers, which work by coupling electromagnetic waves with the electrons that oscillate(振荡,摆动) at the surface of metals to squeeze light into nanoscale spaces far past its natural diffraction limit of half a wavelength5. Last year, Zhang's team reported a plasmon laser that generated visible light in a space only 5 nanometers wide, or about the size of a single protein molecule.

But efforts to exploit such advancements6 for commercial devices had hit a wall of ice.

"To operate properly, plasmon lasers need to be sealed in a vacuum chamber7 cooled to cryogenic temperatures(制冷温度,低温) as low as 10 kelvins, or minus 441 degrees Fahrenheit8, so they have not been usable for practical applications," said Renmin Ma, a post-doctoral researcher in Zhang's lab and co-lead author of the Nature Materials paper.

In previous designs, most of the light produced by the laser leaked out, which required researchers to increase amplification9 of the remaining light energy to sustain the laser operation. To accomplish this amplification, or gain increase, researchers put the materials into a deep freeze.

To plug the light leak, the scientists took inspiration from a whispering gallery, typically an enclosed oval-shaped room located beneath a dome10 in which sound waves from one side are reflected back to the other. This reflection allows people on opposite sides of the gallery to talk to each other as if they were standing11 side by side. (Some notable examples of whispering galleries include the U.S. Capitol's Statuary Hall, New York's Grand Central Terminal, and the rotunda12 at San Francisco's city hall.)

Instead of bouncing back sound waves, the researchers used a total internal reflection technique to bounce surface plasmons back inside a nano-square device. The configuration13 was made out of a cadmium sulfide(硫化镉) square measuring 45 nanometers thick and 1 micrometer long placed on top of a silver surface and separated by a 5 nanometer gap of magnesium14 fluoride.

The scientists were able to enhance by 18-fold the emission15 rate of light, and confine the light to a space of about 20 nanometers, or one-twentieth the size of its wavelength. By controlling the loss of radiation, it was no longer necessary to encase the device in a vacuum cooled with liquid helium. The laser functioned at room temperature.

"The greatly enhanced light matter interaction rates means that very weak signals might be observable," said Ma. "Lasers with a mode size of a single protein are a key milestone16 toward applications in ultra-compact light source in communications and biomedical diagnostics. The present square plasmon cavities not only can serve as compact light sources, but also can be the key components17 of other functional18 building-blocks in integrated circuits, such as add-drop filters, direction couplers(耦合器,连接器) and modulators(调节器) ."


1 utilization Of0zMC     
  • Computer has found an increasingly wide utilization in all fields.电子计算机已越来越广泛地在各个领域得到应用。
  • Modern forms of agricultural utilization,have completely refuted this assumption.现代农业利用形式,完全驳倒了这种想象。
2 investigator zRQzo     
  • He was a special investigator for the FBI.他是联邦调查局的特别调查员。
  • The investigator was able to deduce the crime and find the criminal.调查者能够推出犯罪过程并锁定罪犯。
3 faculty HhkzK     
  • He has a great faculty for learning foreign languages.他有学习外语的天赋。
  • He has the faculty of saying the right thing at the right time.他有在恰当的时候说恰当的话的才智。
4 molecule Y6Tzn     
  • A molecule of water is made up of two atoms of hygrogen and one atom of oxygen.一个水分子是由P妈?f婘??妈?成的。
  • This gives us the structural formula of the molecule.这种方式给出了分子的结构式。
5 wavelength 8gHwn     
  • The authorities were unable to jam this wavelength.当局无法干扰这一波长。
  • Radio One has broadcast on this wavelength for years.广播1台已经用这个波长广播多年了。
6 advancements d9d88b0aa041a51f56ca9b4113bf311c     
n.(级别的)晋升( advancement的名词复数 );前进;进展;促进
  • Today, the pace of life is increasing with technological advancements. 当今, 随着科技进步,生活节奏不断增快。 来自《现代汉英综合大词典》
  • Great advancements in drought prediction have been made in recent years. 近年来,人们对干旱灾害的预报研究取得了长足的进步。 来自互联网
7 chamber wnky9     
  • For many,the dentist's surgery remains a torture chamber.对许多人来说,牙医的治疗室一直是间受刑室。
  • The chamber was ablaze with light.会议厅里灯火辉煌。
8 Fahrenheit hlhx9     
  • He was asked for the boiling point of water in Fahrenheit.他被问到水的沸点是华氏多少度。
  • The thermometer reads 80 degrees Fahrenheit.寒暑表指出华氏80度。
9 amplification pLvyI     
  • The voice of despair may be weak and need amplification.绝望的呼声可能很微弱,需要扩大。
  • Some of them require further amplification.其中有些内容需进一步详细阐明。
10 dome 7s2xC     
  • The dome was supported by white marble columns.圆顶由白色大理石柱支撑着。
  • They formed the dome with the tree's branches.他们用树枝搭成圆屋顶。
11 standing 2hCzgo     
  • After the earthquake only a few houses were left standing.地震过后只有几幢房屋还立着。
  • They're standing out against any change in the law.他们坚决反对对法律做任何修改。
12 rotunda rX6xH     
  • The Capitol at Washington has a large rotunda.华盛顿的国会大厦有一圆形大厅。
  • The rotunda was almost deserted today,dotted with just a few tourists.圆形大厅今天几乎没有多少人,只零星散布着几个游客。
13 configuration nYpyb     
  • Geographers study the configuration of the mountains.地理学家研究山脉的地形轮廓。
  • Prices range from $119 to $199,depending on the particular configuration.价格因具体配置而异,从119美元至199美元不等。
14 magnesium bRiz8     
  • Magnesium is the nutrient element in plant growth.镁是植物生长的营养要素。
  • The water contains high amounts of magnesium.这水含有大量的镁。
15 emission vjnz4     
  • Rigorous measures will be taken to reduce the total pollutant emission.采取严格有力措施,降低污染物排放总量。
  • Finally,the way to effectively control particulate emission is pointed out.最后,指出有效降低颗粒排放的方向。
16 milestone c78zM     
  • The film proved to be a milestone in the history of cinema.事实证明这部影片是电影史上的一个里程碑。
  • I think this is a very important milestone in the relations between our two countries.我认为这是我们两国关系中一个十分重要的里程碑。
17 components 4725dcf446a342f1473a8228e42dfa48     
(机器、设备等的)构成要素,零件,成分; 成分( component的名词复数 ); [物理化学]组分; [数学]分量; (混合物的)组成部分
  • the components of a machine 机器部件
  • Our chemistry teacher often reduces a compound to its components in lab. 在实验室中化学老师常把化合物分解为各种成分。
18 functional 5hMxa     
  • The telephone was out of order,but is functional now.电话刚才坏了,但现在可以用了。
  • The furniture is not fancy,just functional.这些家具不是摆着好看的,只是为了实用。
TAG标签: room temperature lasers