Phase-matched second harmonic generations in poled polymer films based on poly (methyl methacrylate) containing a p-aminophenyl-cyclobutenedione moiety as the side chains

Poled polymer films containing a nonlinear optical active moiety (cyclobutenedione derivative) as the side chains were prepared and applied to frequency doublings in guided-wave structures. A (p-aminophenyl) cyclobutenedione containing monomer, l-{4-[N-(2-methacryloyloxyethyl)-N-methyl-amino]-phenyl}-2-methylaminocyclobutene-3,4-dione [CD1-MA] was newly synthesized. For less than 20 wt% concentration, amorphous copolymers of CD1-MA with methyl methacrylate showed the glass transition at around 125°C. The copolymers were crystalline at higher dye concentrations. The d₃₃ value of the poled polymer film with 10 wt% of CD1-MA concentration was estimated as 8.1 pm·V-1 by the Maker fringe method. Second harmonic waves of Nd:YAG laser (1064 nm) were observed in three-layer optical waveguides (air / poled polymer / pyrex glass) for the collinear type and the Cerenkov type phase matchings.