Patent ID: 6761999
Filing Date: 2004-07-13
Classification: B82Y,G02F,G03H

Abstract:
A method for femtosecond nondegenerate four-wave mixing in charge-transfer materials to produce an ultrafast, transient holographic grating, which comprises the steps of:(a) preparing a mixture of a charge-donor species, wherein the charge-donor species includes semiconducting polymers that absorb light in a first wavelength region with a charge-acceptor species, such that charge transfer occurs between the charge-donor species and the charge-acceptor species when the mixture is excited by the light within the first wavelength region; (b) exciting the mixture with two femtosecond scale pulsed light beams within the first wavelength region, the two pulsed light beams overlapping in the mixture and having an angle therebetween, each of the two pulsed light beams having a pulse width less than the time required for charge to be transferred back from the charge-acceptor species to the charge-donor species, whereby an ultrafast, transient holographic grating is formed in the region of the mixture surrounding the overlapping of the two light beams; (c) passing light within a second wavelength region through the holographic grating region of the blend, wherein the light within the second wavelength region is chosen so as not to be absorbed by the mixture in the absence of charge transfer; and (d) detecting the diffracted light within the second wavelength region.