Dynamic amplitude gratings in liquid crystals

A new approach for producing dynamic amplitude holograms in liquid crystals is proposed. A steady-state amplification of a probe wave should occur at gratings of the orientation of the molecules of a nematic liquid crystal when an orthogonally polarized pump is used. A threshold must be reached for this amplification to occur. A difference between the attenuation of the ordinary wave and that of the extraordinary wave plays a fundamental role in this process. The role played by heat evolution is determined. Under certain conditions, heat evolution can lower the amplification threshold.