A New Gatekeeper for Light (IMAGE) University at Buffalo Caption A photograph (left) shows the experimental set-up used to confirm the existence of the Bloch wave resonance, which was first predicted theoretically. An illustration (right) shows the interior of the experimental device, called a hollow periodic waveguide, which consists of two corrugated metallic plates separated by a variable distance of about one inch, and the upper plate can slide with respect to the lower. When researchers shot microwaves between the plates through the air, they were able to control which wavelengths of microwaves were allowed through by varying the position of the upper plate. Credit Credit: Lab of Victor Pogrebnyak/University at Buffalo Usage Restrictions This image may only be used with news reports discussing the research outlined in the associated press release. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.