A semiconductor device can amplify the tiny signal from incoming photons using much less power and creating much less noise than current methods.

Previously, converting a signal from photons into a usable electrical signal required the use of two devices running at relatively high voltages — one device to convert the photon to an electrical signal and another to amplify it.

Yu-Hwa Lo at the University of California, San Diego, and his colleagues exploited a different amplification mechanism to consolidate the process into a single device. By engineering a special junction between layers of silicon with two different kinds of impurities, the team amplified the light signals by more than a factor of 4,000 and induced 30 times less noise in the signal than conventional methods.

Appl. Phys. Lett. 107, 053505 (2015)