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 …
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In order to account for the way phase conjugate wave systems communicate it is absolutely essential to consider faster than light wave-phase velocities. We have long been working on a detailed model for how golden ratio vortex phase conjugation produces faster than light speeds.
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