Re: problems with beaming

[T.L.G.vanderLinden@student.utwente.nl (Timothy van der Linden)]

To Lee,

>Not necessarily, it depends upon what type of laser you are discussing. Two
>types seem to be popular here for two very different reasons. One is a
>simple laser augmented solar sail which is propelled solely by the pressure
>of light. With a properly constructed sail, this can utilize almost ANY
>frequency of radiation, so the easiest way to decrease the aperture would be
>to increase the frequency.

In this case something like far ultra violet or Rontgen waves may decrease
the size of the aperture by a thousandfold (compared to visible light). 
Do you know if there are lasers that can transmit EM-radiation with these
wavelenths?

>I am not sure if phased array can be applied adequately to shorter
>wavelengths or not. I am not aware of any current research in this area. If
>it can, then lasers also become practical. Solar pumped yellow light lasers
>should be relatively cheap and easy to build and conversion efficiencies and
>loss ratios would not be too much of a concern.

Phased lasers are these femto or pico second lasers, right?


Timothy

P.S. could you tell me what the ~ in sin(theta)~theta=1.22*lambda/d means?