it is kinda late in the AM for me to post this but here ya go:
From last night "Nonlinear optics
Phase conjugate wave
The phase conjugation process can be thought of as the generation of a time-reversed wavefront. If the input signal wave in passing through a medium before entering the phase-conjugate mirror suffers a wavefront distortion, the phase conjugate wave reflected back through the medium will remove this distortion.
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From a practical perspective this implies that a phase-conjugate mirror can generate a wave propagating in reverse to the incident wave whose amplitude is the complex conjugate of the incident wave. Thus, the wavefronts of the reverse wave coincide with those of the incident wave. This concept is illustrated in Fig. 8.7.
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The phase conjugate wave was apparently discovered by Nikola Tesla. This was the secret of his wireless transmission of energy at a distance without losses. Transmitting time-reversed waves resulted in transmission of convergent, hence energy-conserving, beams. Tesla described it as if he had an invisible wire through the vacuum, and …
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Phase conjugation by four-wave mixing with a nonstationary pumping wave. … Exact solutions for the impulse responses of the phase-conjugate backward wave and of the transmitted forward wave in a …"
Then it occured to me that the unit circle/spiral of the EM wave would create a circuit of the unit circle (imaginary plane) if it was 90 degrees applied in dual wave form and be what Tesla was thinking about - me"so instead of cancelation he was spinning the animation 90 degrees completing the circle with two EM fields filling all 4 quadrants. The invisible wire is the center unit circles that are 90 degrees apart completing the Electric cycle as one and the Magnetic cycle as the 90 degree offset. That completes the circuit in the projection plane."