科学家找到使白炽灯发光效率到达100%的途径！
本帖最后由 precession 于 2009-6-4 14:10 编辑这篇文章的大概意思是：用飞秒激光对钨丝进行表面处理，可使其表面形成纳米大小的脊装突起（ridges），这些突脊能够促使热激发的表面“等离子基元”（plasmons）与自由空间的电磁辐射相耦合，从而提升辐射率…………
这可是要发表在物理学权威刊物《Physical Reviews Letter》上的文章奥，不是闹着玩的
Jun 3, 2009
Laser boosts light bulb efficiency
http://images.iop.org/objects/physicsweb/news/thumb/13/5/29/guo.jpg
Chunlei Guo, University of Rochester
The prevalence of cold, blue energy-saving light bulbs might soon begin to fade. That’s according to researchers in the US, who claim to have discovered how to make traditional incandescent bulbs 100% efficient.
“Many people still love incandescent light bulbs because they create the most pleasant light and are cheaper to buy,” Chunlei Guo of the University of Rochester, New York, told physicsworld.com. “The downside is the low efficiency of the conventional incandescent bulbs. This research addresses that very problem.”
Guo, together with colleague Anatoliy Vorobyev, made the discovery having spent several years investigating how intense laser pulses can affect the structure of metal surfaces. In 2006 the two researchers found that by applying a series of femtosecond (10-15 second) laser bursts to a metal, its surface would become pitch black. In other words, the metal’s ability to absorb light would soar.
But according to Kirchhoff’s law, at thermal equilibrium the absorptivity of a surface equals its emissivity. So Guo and Vorobyev figured the same “blackening” technique could enhance the emission, and hence efficiency, of an incandescent bulb’s metal filament.
Kirchoff’s law standsTo see if this could work, the researchers used an amplified laser to expose part of a tungsten filament to a number of 65-femtosecond pulses at a wavelength of 800 nm and a repetition rate of 1 kHz. Once they had inserted the blackened filament inside a bulb, they pre-heated it to its equilibrium temperature of 900°C before monitoring its emission with a photomultiplier tube.
Guo and Vorobyev found that the number of laser pulses given to the filaments strongly affected the emission. Up to about 500 pulses there was a sharp increase, while towards 4000 pulses the increase levelled out. The researchers also found that the enhancement depended on the wavelength of light emitted from the bulb — at 400 nm the increase was about 25% but at 800 nm the increase rose to 55%.
Scanning-electron-microscopy images showed the laser pulses had caused the tungsten surface to adopt a structure of periodic, nano-sized ridges. The researchers believe these ridges encourage thermally excited surface “plasmons” — quanta of plasma oscillations — to couple with electromagnetic emission in free space, and thereby boost emissivity.
Super efficientGuo says that, over the entire visible spectrum, the efficiency rose from roughly 50% to 100%. However, Shawn Lin, a photonics researcher at the Rensselaer Polytechnic Institute in Troy, New York, is not so sure. “The higher emissivity is over visible and near-infrared wavelengths, which means it would generate a lot of wasted heat — 80 to 95% — in the infrared regime,” he says. If there is wasted heat, adds Lin, the researchers could reduce it by further nano-structuring.
Nevertheless, according to the researchers, the boosted efficiency is not the only benefit of the technique. Guo and Vorobyev found that the strength and duration of the laser treatment could alter the colour balance of the emission. Moreover, they found that the emission was somewhat polarized, possibly because of the direction of the surface ridges.
“Light polarization has a variety of applications, from liquid crystal displays to polarized sunglasses,” explains Guo. “If we start to illuminate with polarized light, a wide variety of perceptive effects can be achieved, such as brightness and clarity.”
However, the immediate future may not be looking too dark for today’s energy saving bulbs — the possibility of commercial devices is not yet at the front of the researchers’ minds. “The research just came out,” says Guo. “This is too early to say at this point.”
This research will be published tomorrow in Physical Review Letters.
About the authorJon Cartwright is a freelance journalist based in Bristol, UK 本帖最后由 silrock 于 2009-6-4 13:19 编辑
好东西~哪个公司快量产吧 2# silrock
The possibility of commercial devices is not yet at the front of the researchers’ minds
达到100%？要我我不信，除非发明这东西的人能看见红外线 肯定不是100%。。。 是比现有灯泡效率提高“最多"100%
over the entire visible spectrum, the efficiency rose from roughly 50% to 100%
20-30流明/瓦变成40-60流明/瓦 可是这些纳米结构在通电钨丝蒸发下是不是很快被破坏？ 得多少钱一个？ 4# POWER_RDX
的却令人感到不可思议，不过 零电阻的超导不是也令人不可思议过嘛！
在wikipedia上找到一段话（只有英文的），关于“plasmon”的解释。
In physics, a plasmon is a quantum of plasma oscillation. The plasmon is the quasiparticle resulting from the quantization of plasma oscillations just as photons and phonons are quantizations of light and sound waves, respectively. Thus, plasmons are collective oscillations of the free electron gas density, often at optical frequencies. They can also couple with a photon to create a third quasiparticle called a plasma polariton. 更正为提高100%。。。。 要想多了解的话，还是看看明天将发表在PRL上的文章吧！http://prl.aps.org/ 超导有什么不可思议的？
大家都说了，是提高100%，而不是达到100%，不要再执迷不悟了 有这可能，完全没有损耗。 超导有什么不可思议的？
大家都说了，是提高100%，而不是达到100%，不要再执迷不悟了
POWER_RDX 发表于 2009-6-4 15:02 http://www.shoudian.org/images/common/back.gif
然，也就是光效提高到原来两倍的水平。即使这样也不能100％转化电能为可见光。 真的有那么一天就好了 最关注的还是灯泡的寿命有没有提高，不然还是没有竞争力 没什么兴趣啊 楼主是标题党，明明是效率提高50-100%而已，这有啥好奇怪的。
当然这不否认这个发现的伟大意义，但目前离商品化还有很长的路呢，到时LED又不知变成怎样了。 Rochester，申请过这所学校的博士后
不知道提高的基准是多少，20lm/W？ 很多研究为了让结果更漂亮，把对照组的数据选得比较低。 继续盖楼