NIST Photon Detectors Have Record Efficiency

http://www.nist.gov/public_affairs/techbeat/tb2005_0602.htm#photon

Sensors that detect and count single photons, the smallest quantities of light, with 88 percent efficiency have been demonstrated by physicists at the National Institute of Standard and Technology (NIST). This record efficiency is an important step toward making reliable single photon detectors for use in practical quantum cryptography systems, the most secure method known for ensuring the privacy of a communications channel.