Hark! Group Demonstrates First Heralded Single Photon Source Made from Silicon (image) National Institute of Standards and Technology (NIST) Share Print E-Mail Caption This is an illustration of the process of photon pair generation, in which input pump photons spontaneously generate special pairs of new photons that emerge at precisely the same time, with one at a slightly lower frequency and the other a slightly higher frequency, after which heralding occurs. Credit Srinivasan, Davanco/NIST 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.