Richard Clark wrote:

Cecil Moore wrote:
When you superpose two 100w coherent laser beams, the resultant
power is indeed 400w

Yowza! You, with W's help, can roll your Social Security over into
investments in the CB amplifier Market.

Note the
following extremely important qualification. The extra power
must come from somewhere, either from the two sources or from
destructive interference. So says Hecht.

When you phasor add 100v to 100v, what V^2/Z0 do you get?

and must be supplied by the sources or or supplied by
destructive interference from somewhere else.

[Hecht rolling his eyes] So, this means that Hecht's formula only
works for steady state? :-)

Yep, irradiance is a quantity averaged over time. It is
steady-state by definition, an accumulated effect.

If both are 100W pulses, and the lasers are off before the target are
pulse illuminated -um-
1.) 100W
2.) 200W
3.) 400W
4.) no hundred W

You will get interference rings of 400w/unit-area and
rings of 0w/unit-area all averaging out to 200w total.
All this is covered in _Optics_. Please spare us your
ignorance and read the book.

If the sources are incapable of supplying the extra power,
For every P1+P2+2*SQRT(P1*P2), i.e. constructive interference,
there is a P1+P2-2*SQRT(P1*P2), i.e. destructive interference.
--
73, Cecil, http://www.qsl.net/w5dxp

----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==----
http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----