Stacking the Deck: Single Photons Observed at Seemingly Faster-than-Light Speeds (1 of 2) (image) National Institute of Standards and Technology (NIST) Share Print E-Mail Caption A single photon travels through alternating layers of low (blue) and high (green) refractive index material more slowly (top) or quickly (bottom) depending upon the order of the layers. A strategically placed additional layer (bottom) can dramatically reduce photon transit time. Credit JQI Usage Restrictions None Share Print E-Mail 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.