All-optical spatial light modulator with surface plasmon resonance

An all-optical photoaddressed spatial light modulator has been demonstrated. The device consists of a prism of high refractive index coated with a thin silver film and a dye-doped polymer film. The writing beam photothermally changes the distribution of the refractive index of the dye-doped film. The reading beam, of a different wavelength, which is incident upon the prism near an angle for surface plasmon resonance at the metal–dye-doped-film interface, undergoes modulation on reflection. Both positive and negative modulation is possible when suitable angles of incidence are chosen for the reading beam. We obtained a resolution of 15 line pairs/mm, an ∼10-s rise time, a 2-s fall time.