Practical quantum cryptography in free space

W. T. Buttler, R. J. Hughes, P. G. Kwiat, S. K. Lamoreaux, G. G. Luther, G. L. Morgan, J. E. Nordholt, C. G. Peterson, C. M. Simmons, A. G. White

Research output: Contribution to conferencePaperpeer-review


The quantum cryptography, or quantum key distribution (QKD) in free space over an outdoor optical path of approximately 950 m under nighttime conditions was demonstrated. The success of free-space QKD against a high background depends on the transmission and detection of single photons through optically thick and turbulent medium. A combination of sub-nanosecond tuning, narrow filters, spatial filtering, and adaptive optics can render the difficult detection problem tractable. The nonbirefringent nature of the atmosphere at optical wavelengths allows the transmission of the single-photon polarization states used in the free-space QKD protocol.

Original languageEnglish (US)
Number of pages2
StatePublished - 1998
Externally publishedYes
EventProceedings of the 1998 International Quantum Electronics Conference - San Francisco, CA, USA
Duration: May 3 1998May 8 1998


OtherProceedings of the 1998 International Quantum Electronics Conference
CitySan Francisco, CA, USA

ASJC Scopus subject areas

  • General Physics and Astronomy


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