ADVERTISEMENT
2 /3 FREE ARTICLES LEFT THIS MONTH Remaining
Chemistry matters. Join us to get the news you need.

If you have an ACS member number, please enter it here so we can link this account to your membership. (optional)

ACS values your privacy. By submitting your information, you are gaining access to C&EN and subscribing to our weekly newsletter. We use the information you provide to make your reading experience better, and we will never sell your data to third party members.

ENJOY UNLIMITED ACCES TO C&EN

Materials

Metal-free metamaterials switch between blocking and transmitting light

Removing metals opens up possibilities for the engineered structures

by Mitch Jacoby
August 21, 2016 | APPEARED IN VOLUME 94, ISSUE 33

A flash of light is all it takes to convert a metal-free metamaterial from a state that blocks certain wavelengths of light to one that transmits them, according to a study (App. Phys. Lett. 2016, DOI: 10.1063/1.4959272). The advance could lead to photonic and optoelectronic devices for use in telecommunications and other areas.

Metamaterials exhibit unnatural properties—for example, the ability to selectively reflect, absorb, or transmit light or sound—by virtue of the geometry of their engineered structures. Many metamaterials are made from metals. This includes versions that switch between “on” and “off” states in response to electric or thermal stimulus. Because metals generally absorb visible and infrared light, these metamaterials can’t be used in various optical devices.

So Kevin F. MacDonald and coworkers at the University of Southampton used a 300-nm-thick film of germanium antimony telluride (Ge2Sb2Te5), or GST, to make a grating featuring parallel lines of GST, roughly 750 nm wide, spaced apart by 130 nm. GST is a phase-change material widely used in DVDs as a data storage medium.

The grating blocks the transmission of near-IR wavelengths between 1,300 and 1,600 nm. But when irradiated with green laser light, GST switches from amorphous to crystalline, making the grating transparent at these wavelengths. The team is now working to encapsulate GST between protective layers of ZnS and SiO2, as is done with DVDs, to avoid damaging the grating when it is briefly heated to switch it back to its amorphous state.

X

Article:

This article has been sent to the following recipient:

Leave A Comment

*Required to comment