Detectability of Extraterrestrial Technological Activities

Optical Waves

       In the radio domain, there have been several proposals  to  use  the
       visible region of  the  spectrum  for  interstellar  communications.
       Since the first proposal by Schwartz  and  Townes  (1961), intensive
       research has been  performed  on  the  possible use  of  lasers  for
       interstellar communication.

       Ross (1979) examined  the  great advantages of using short pulses in
       the nanosecond regime at high energy  per  pulse  at  very  low duty
       cycle.

       This proposal was  experimentally explored by Shvartsman  (1987) and
       Beskin (1993), using a Multichannel Analyzer of Nanosecond Intensity
       Alterations (MANIA), from  the  six-meter telescope in Russia.  This
       equipment allows photon arrival  times  to  be  determined  with  an
       accuracy of 5x10exp(-8)  seconds,  the  dead time being  3x10exp(-7)
       seconds and the  maximum  intensity  of  the incoming photon flux is
       2x10exp4 counts/seconds.