Ultrafast all-optical spatial light modulation based on complex refractive index changes of copper phthalocyanine-doped polymer film upon photoexcitation in guided mode geometry
摘要
Ultrafast all-optical reflectance control was achieved by photoinduced complex refractive index changes in thin poly(vinyl alcohol) (PVA) films containing water-soluble phthalocyanine at the incident angle corresponding to a sharp guided mode resonance upon excitation with a ns pulsed laser as a writing beam. The rise time of reflectance was less than 20 ns and the fall time was controlled by the lifetime of the excited triplet phthalocyanine, 31 ns for copper phthalocyanine (CuPcS). The spatial resolution was determined to be better than about 3μm by using a photochromic dye. The present system based on photoexcitation of CuPcS will allow all-optical spatial light modulation upto about 30 MHz.