Photon-counting optical coherence-domain reflectometry using   superconducting single-photon detectors
  We consider the use of single-photon counting detectors in coherence-domain imaging. Detectors operated in this mode exhibit reduced noise, which leads to increased sensitivity for weak light sources and weakly reflecting samples. In particular, we experimentally demonstrate the possibility of using superconducting single-photon detectors (SSPDs) for optical coherence-domain reflectometry (OCDR). These detectors are sensitive over the full spectral range that is useful for carrying out such imaging in biological samples. With counting rates as high as 100 MHz, SSPDs also offer a high rate of data acquisition if the light flux is sufficient. 
Nishant Mohan, Olga Minaeva, Gregory N. Goltsman, Magued B. Nasr,   Bahaa E. A. Saleh, Alexander V. Sergienko, and Malvin C....