Nonlinear Wave Mixing

Louis de Broglie

Tomasz Wasak, V. V. Konotop, Marek Trippenbach

The theory of the four-wave mixing in nonlinear lattices is presented. Nonlinear lattice modifies the momentum conservation condition and leaves energy conservation unaffected, contrary to the more conventional linear modulation. We study the dynamics of the moving wavepacket in the presence of a nonlinear lattice and observe the formation of two new waves which is not possible in the conventional four-wave mixing process. We design an analytical plane-wave model which agrees well with numerical simulations.

Iwo Białynicki‐Birula, Jerzy Mycielski

U. Bortolozzo, S. Residori, Jean‐Pierre Huignard

Slow-light is obtained through nonlinear wave-mixing in a liquid crystal light-valve. A deceleration of light pulses down to group velocities as small as 0.2 mm/s is achieved when two-wave-mixing is performed with a continuous pump and a time modulated signal. A model accounts for the observations in the general framework of nonlinear wave-mixing in thin media. The large group delay provided by the light-valve is exploited to enhance the spectral sensitivity of an interferometer, whereas the narrow frequency bandwidth of the two-wave-mixing gain is used to realize an adaptive holographic system that allows achieving subpicometer detection.

Pochi Yeh

Mingjun Chi, Jean‐Pierre Huignard, Paul Michael Petersen

A general theory of two-wave mixing (TWM) in nonlinear media is presented. Assuming a gain (or absorption) grating and a refractive index grating are generated because of the nonlinear process in a nonlinear medium, the coupled-wave equations of TWM are derived based on Maxwell's wave equation. The coupled-wave equations can be decoupled as coupled equations for the intensity and coupled equations for the phase of both beams, and these two sets of coupled equations can be solved analytically by using average total intensity in the medium instead of using the total intensity. Compared with the previous theory of TWM, the theory presented here is more general, and the applications of the theory to photorefractive materials, Kerr media, and semiconductor broad-area amplifiers are described.