研究人员发现光穿透金属的新方法

Helping¹ bridge the gap between photonics（光电） and electronics, researchers from Purdue University have coaxed² a thin film of titanium nitride（氮化物） into transporting plasmons, tiny electron excitations coupled to light that can direct and manipulate optical signals on the nanoscale. Titanium nitride's addition to the short list of surface-plasmon-supporting materials, formerly³ composed only of metals, could point the way to a new class of optoelectronic（光电子的） devices with unprecedented⁴ speed and efficiency. "We have found that titanium nitride is a promising⁵ candidate for an entirely⁶ new class of technologies based on plasmonics and metamaterials," said Alexandra Boltasseva, a researcher at Purdue and an author on a paper published March 27 in the Optical Society's (OSA) open-access journal Optical Materials Express. "This is particularly compelling（引人注目的） because surface plasmons（胞质基因） resolve a basic mismatch between wavelength-scale optical devices and the much smaller components⁷ of integrated electronic circuits."

Metals carry electricity with ease, but normally do nothing to transmit light waves. Surface plasmons, unusual light-coupled oscillations that form on the surface of metallic⁸ materials, are the exception to that rule. When excited on the surface of metals by light waves of specific frequencies, plasmons are able to retain that same frequency, but with wavelengths⁹ that are orders-of-magnitude smaller, cramming¹⁰ visible and near-infrared light into the realm of the nanoscale.

In the world of electronics and optics, that 100-fold contraction¹¹ is a boon¹². Circuits that direct the paths of electrons operate on a much smaller scale than optical light waves, so engineers must either rely on small but relatively¹³ sluggish¹⁴（萧条的） electrons for information processing or bulk up to accommodate the zippy photons. Plasmons represent the best of both worlds and are already at the heart of a number of optoelectronic devices. They have not had widespread use, however, due to the dearth¹⁵ of materials that readily generate them and the fact that metals, in most cases, cannot be integrated with semiconductor¹⁶ devices.