Through the Looking Glass with Phase Conjugation
Fall 1982
Los Alamos National Laboratory

Many times in my searching through hidden documents and talking to various people... the term "Digging a very deep Rabbit Hole" comes up...

When I was looking at the tech that would be involved in 'cloaking' a secret space ship or station, I was shown the secret of the 'Cheshire Cat' then told by the 'Rabbit' that asking about this information would attract the attention of "The Kings Men'  who wouldn't be able to put 'Humpty Dumpty' together again...

I have it from a private source that over the doorway to S4 at Groom Lake there is a 3D figurine of a Rabbit holding a Watch...

At first I thought this amusing... then I realized there was more to it...

In our Stargate threads we were shown a few documents that were very interesting... and led us to  the "Looking Glass"

Join me now as we follow 'Alice' into the 'Rabbit Hole' and step through the "Looking Glass' at Los Alamos National Laboratory...

I would suggest d/ling this quickly they already moved the Warp Drive papers

 

"I don't understand . . .' " said Alice. "It's dreadfully confusing!"
"That's the effect of living backwards," the Queen said kindly: "it always makes one a little giddy at first- ''
"Living backwards!" Alice repeated in great astonishment. "I never
heard of such a thing!"
-Lewis Carroll

Abstract:

Imagine a mirror that reflects more light than was incident, that reflects a beam into the same direction regardless of the mirror's tilt, that eliminates image distortions by causing light rays to retrace their paths as if running backward in time, and that when looked at allows the observer to see absolutely nothing.

Science fiction, you say? Well, such mirrors have been the subject of intense investigation both here at Los Alamos and at other research laboratories around the world. Not only do they exist, but their practical applications may be far-reaching.

PDF FILE
http://library.lanl.gov/cgi-bin/getfile?06-01.pdf - (Archived)
 

71-07-04 ACTIVE SONAR SIGNAL PROCESSING BASED ON TIME-REVERSAL OR PHASE-CONJUGATION

82-07-01 SPACECRAFT & OPERATIONALLY RESPONSIVE SPACE
(ORS) TECHNOLOGY

The complete BAA can be found at our website:
http://heron.nrl.navy.mil/contracts/0708baa/baa.htm.

baa0701newtopics.pdf
 

A.J. Schmitt, R.H. Lehmberg, J.A. Gardner, and S.E. Bodner, Fusion Technology Institute,
University of Wisconsin UWFDM-651 (Sept. 1985).
Lehmberg.NRL.Memo.5980.1987.pdf

Laser Beam Coherent Combining Using Multiplexed Volume Holographic Optical Elements and Phase Conjugation
NewsletterApr07.pdf
 

Our current emphasis is on a communications algorithm based on a version time-reversal signal processing called passive phase conjugation [Rouseff et al. 2001]. In this approach, one uses a receiving array and matched filters based on estimating channel’s time-varying impulse response. The specific version of phase conjugate processing has two crucial communications design parameters: the length of thematched filters, and the interval at which these estimates are updated [Flynn et al. 2004]. We examine how the optimal values for these two parameters vary with the source-to-receiver range and with local environmental conditions.

D. Rouseff, “Intersymbol interference in underwater acoustic communications using time-reversal signal processing,” J. Acoust. Soc. Am. 117, 780-788 (2005).

oarousef.pdf

FINITE DIFFERENCE TIME DOMAIN, FDTD…
PROPAGATION MODELING

SOURCE LOCATION USING TIME REVERSAL
PROCESSING

Time reversal processing involves the following steps:
First, the sound signature produced by a source is recorded at
a number of sensor locations after propagation through the
complex medium; next, the time series signatures are reversed
in time; finally, the reversed time series are emitted
from the sensor locations and propagate back through the
complex medium. Because of the symmetry of the wave
equation, this procedure will refocus acoustic energy at the
original source location.
The time reversal steps were performed using the FDTD
model for the urban situation shown in Fig. 1, and Fig. 2
shows wave field snapshots of the process using eight NLOS
sensors. In the final panel, acoustic energy can be seen focusing
at the original source location
shown with an x in
Fig. 1. In Fig. 3, the final results of time reversal processing
are compared for the same case with eight NLOS sensors,
and for a case where only three NLOS sensors are used. Both
cases find the correct source location, although the result is
stronger for the case with eight sensors compared to the case
with three sensors.
To apply the time reversal method in an actual urban
area, the building locations, sensor locations, and time signatures
are required.With this information the method can be
applied to find unknown source locations using the FDTD
model as demonstrated earlier. However, before this method
could be used in practice, for example to locate gunshots in
near real time, the calculation time will need to be decreased
by about three orders of magnitude. In addition, further study
of this technique is needed to determine the resistance of the
method to errors in sensor or building locations and to ambient
noise. Despite these requirements, the method could become feasible for application to a specific location with
fixed and known sensor and building locations, if a precomputing
strategy similar to Ref. 28 was used.

JASA2005TimeReversalForSourceLocationUrbanEnvironment
 

ompor014.pdf