‘Gatekeeper’ material could act as optical switch

1 min read

Researchers from the University at Buffalo’s School of Engineering and Applied Sciences have discovered that if a non periodic material is sandwiched between two boundary layers of material with a periodic shape, the result will be transparent to certain wavelengths of light and opaque to others. The team has also found that, by moving one of the boundaries, the wavelengths allowed through can be changed.

Describing such material as a ‘gatekeeper’, the team says applications could include electronic and optical devices, including those that rely on transistors or other components that switch on and off.

The structure of a periodic material comprises parts that repeat, such as crystals. Bragg’s Law will show which wavelengths will pass through and which will be blocked. However, the researchers say that a completely periodic material structure is not needed predictable reflection and add the effect not only applies to light waves, but also to a broad range of wave phenomena.

“We have shown that Bragg’s Law is a special case of a more generalised phenomenon that was discovered in this study and named as a Bloch wave resonance,” said researcher Victor Pogrebnyak. “This opens up new opportunities in photonics, nanoelectronics, optics and acoustics.”

“Electrons behave as waves that can also exhibit a Bloch resonance,” said Professor Edward Furlani, “which can be used as a powerful method to control currents in nanoelectronic circuits.”

Applications that could take advantage of this development include white light lasers and a new type of fast switching transistor.