All-optical delay of images by backward four-wave mixing in   metal-nanoparticle composites
  We theoretically study a novel method for all-optical delay of images based on backward four-wave mixing in composites containing metal nanoparticles. In this approach a delayed phase conjugate probe pulse is generated by the interaction of two counter-propagating pump beams and a non-collinear shaped probe pulse in the nanocomposite.The fractional delay and the reflectivity for the phase-conjugate signal pulses are studied as function of the input pump intensity. It is shown that this scheme can be used for delayed imaging combined with the elimination of optical diffraction. The advantages of this method include minituarized design, tunable wavelength range up to the telecommunication range and wide bandwidth. 
Kwang-Hyon Kim, Anton Husakou, and Joachim Herrmann
physics.optics