Non-linear optical device sensitive to green laser

A method for modulating light, comprising the steps of:

• providing a photorefractive composition consisting essentially of a chromophore and a polymer, wherein the polymer comprises a repeating unit that includes a moiety selected from the group consisting of the following structures:
• wherein each Q in (M-2) and (M-3) independently represents an unsubstituted or substituted alkylene group;
• wherein Rb1-Rb27 and Rc1-Rc14 in (M-2) and (M-3) are each independently selected from the group consisting of hydrogen, C1-C10 alkyl, C4-C10 aryl and C4-C10 heteroaryl;
• wherein the chromophore and the polymer are together selected to render the composition photorefractive upon irradiation by a green laser;
• wherein the chromophore is 4-homopiperidino-2-fluorobenzylidene malononitrile;
• and
• irradiating the photorefractive composition with a green laser to thereby modulate a photorefractive property of the polymer.