1 kW (SETI) Signals At 1000 Light Years
This graph shows the relative efficacy of the three types of cw beacons at a range of 1000 light years. This range encompasses about 1 million solar-type stars. Clearly, if diffraction-limited performance is allowed for the optical systems, then the visible optical link is superior to the microwave, despite what has been previously suggested in most of the SETI literature. Note however, that the very modest 1 kW transmitters modelled here would not be detectable at visible wavelengths in a 1 Hz bandwidth without signal integration.
Interstellar absorption by dust and grains in the galactic plane is insignificant at visible wavelengths out to ranges of several thousand light years.
Compare this graph to 9301-027.
For more information see 9008-004.
The Columbus Optical SETI Observatory