I was on a hunt to help out a fellow looking for cavitrons and found
this intriguing and very brief page about nonlinear amplification of
phase conjugated waves ABOVE the 'overthreshold regime'....could someone
explain this a bit better....it LOOKS like they are indicating overunity
gains which is precisely what Bearden refers to with four wave mixing
and/or phase conjugation to produce nonlinear effects. I was once told
a 'spook story' about a guy who did a test with phase conjugated laser
beams and got a tremendous amount of power, much more than was input
from the unit....the next day, he was shot as he left his home...that
was the story at any rate....check it out;
http://frontpage.crdf.inter.net/Abstracts/fund/RE1270.html
The purpose of the proposed investigation is to develop and advance the
principles underlying applications of ultrasonic wave phase conjugation
(VVTC) phenomena.
As in optics, extraordinary possibilities are provided by WPC in
acoustics, e.g., self-compensation for phase distortion selftargeting of
ultrasonic beams onto objects, and lenseless acoustic imaging.
Our investigations shall utilize a parametric method of real time WPC
with amplification. In this approach, extremely intense conjugate waves
will be generated, specifically, in the regime of operation above the
absolute parametric instability (the so-called overthreshold regime),
leading to enormous amplification of the received signal.
Practical applications require that special attention be devoted to
understanding how WPC is affected by nonlinear wave distortion during
generation and propagation of the powerful conjugate waves.
The research will involve parallel investigations based on theoretical
study, numerical calculations, and extensive experiments that simulate
real, practical conditions. The project should lead to the development
of new ultrasonic methods for use in medicine (diagnostics,
therapeutics, lithotripsy), acoustic microscopy, nondestructive testing,
etc.
-- Jerry Wayne Decker / jdecker@keelynet.com http://keelynet.com / "From an Art to a Science" Voice : (214) 324-8741 / FAX : (214) 324-3501 KeelyNet - PO BOX 870716 - Mesquite - Republic of Texas - 75187