德國(guó)科學(xué)家發(fā)明3D“隱形斗篷”

German scientists have created a three-dimensional "invisibility cloak" that can hide objects by bending light waves.

The findings, published in the journal Science on Thursday, could in the future make it possible to make large objects invisible, but for now the researchers said they were not keen to speculate on possible applications.

"For now these...cloaking devices are just a beautiful and exciting benchmark to show what transformation optics can do," said Tolga Ergin of the Karlsruhe Institute of Technology.

Transformation optics use a class of materials called metamaterials that guide and control light.

In their study, Ergin and his colleagues used photonic crystals with a structure that looks like piles of wood to make an invisibility device, or cloak.

They used the cloak to conceal a small bump on a gold surface -- a bit like hiding a small object underneath a carpet and then making both the bump and the carpet invisible.

The "cloak" was composed of special lenses that work by partially bending light waves to suppress the light scattering from the bump.

"This is very exciting, because mankind has always thought about being invisible or having invisibility cloaks," Ergin told the reporters in a telephone interview. "This is the first proof of principle. It shows that the technique works."

He added, however, that it would be many years before anything as large as a person, car or tank could be made to disappear with this technique.

"There have been proposals in the field of transformation optics for different devices like beam concentrators, beam shifters, super antennas which concentrate light into one point from all directions, and much, much more," he said.

"It is really hard to say what the future will bring, but the field is definitely very broad and the possibilities are very large."

德國(guó)科學(xué)家近日研制出一種通過彎曲光線來(lái)隱藏物體的三維“隱形斗篷”。

這項(xiàng)發(fā)明為大型物體隱形鋪平了道路，但研究人員稱，目前他們并不想去猜測(cè)可能的應(yīng)用形式。這一最新研究成果于上周四在《科學(xué)》期刊上發(fā)表。

德國(guó)卡爾斯魯厄理工學(xué)院的研究人員托爾加•埃爾金說(shuō)：“目前，這種隱形斗篷只是光學(xué)領(lǐng)域一個(gè)‘驚艷’的開始，讓人們知道轉(zhuǎn)換光學(xué)可以做些什么。”

轉(zhuǎn)換光學(xué)通常使用一種“超材料”來(lái)引導(dǎo)和控制光束。

埃爾金及其同事在研究中使用了一種光子晶體來(lái)制造隱形斗篷。這種光子晶體的結(jié)構(gòu)看上去像成堆的木頭。

研究人員使用隱形斗篷來(lái)掩蓋黃金表面的一個(gè)小凸起，其原理就如同將一個(gè)小物體隱藏在地毯下，然后再使這個(gè)凸起和地毯都隱形。

這個(gè)“斗篷”由特殊透鏡組成，它通過部分彎曲可見光線來(lái)抑制凸起發(fā)出的光。

埃爾金在接受一個(gè)電話采訪時(shí)說(shuō)：“這一發(fā)明十分令人激動(dòng)，因?yàn)槿祟愐恢倍枷腚[形或擁有隱形斗篷。這是我們的首個(gè)隱形樣本，看來(lái)這一技術(shù)是可行的。”

但他認(rèn)為，利用上述技術(shù)使人、汽車、坦克等大型物體隱形尚需時(shí)日。

他說(shuō)：“轉(zhuǎn)換光學(xué)領(lǐng)域曾出現(xiàn)過各種有關(guān)光學(xué)設(shè)備的提議，如波束集中器、波束移位器以及可將來(lái)自多個(gè)方向的光集中于一點(diǎn)的超級(jí)天線等等。”

“很難說(shuō)將來(lái)還會(huì)有什么發(fā)明，但轉(zhuǎn)換光學(xué)絕對(duì)是個(gè)范圍廣、充滿無(wú)限可能的領(lǐng)域。”