Second harmonic nonlinear optical properties of disperse red 1 loaded polysulfones
by Lor Sze Keung
xx, 165 leaves : ill. ; 30 cm
Two approaches were employed to prepare polymeric materials for studying second order nonlinear effects, particularly second harmonic generation (SHG) in polysulfones. eff(2)...[ Read more ]
Two approaches were employed to prepare polymeric materials for studying second order nonlinear effects, particularly second harmonic generation (SHG) in polysulfones.
The first approach is based on host and guest system. Nethyl-N-hydroxyethyl-4- (4'-nitrophenylazo)phenylamine (Disperse Red 1 dye) was doped in four different polysulfone resins, viz., po1y(oxy-1,4-phenylenesulfonyl-1,4-phenyleneoxy-1,4-phenyl- eneisopropylidene-1,4-phenylene), poly(phenylene ether sulfone), poly(phenyl sulfone) and poly(3-bicyclo[2.2.1]heptyl-sulfonyl). Their second harmonic generation (SHG) properties were characterized and compared. Those doped systems demonstrate high second order nonlinearity. The observed Xeff(2) is ranged from 11 to 21 pm/V. The merit of polysulfone resins as a host material are good optical clarity, easy film form-ing ability, and fairly high glass transition (Tg) temperatures (140 - 190 [degrees Celsious]. As compared to polyimide of resins they have good resistance to hydrolysis. They are good candidates for electrooptical materials and also good subsitution for PMMA in modelling studies.
We demonstrate for the first time a new approach in preparing second order nonlinear optical films that are imageable. The advantage of this approach is no etching step is necessary in forming a complex pattern. A SH-active dye, Disperse Red 1, was attached to a photooxidized poly(oxy-1,4-phenylenesulfonyl- 1,4- phenyleneoxy-1,4-phenyleneisopropylidene-1,4-phenylene) surface. Complex pattern can be achieved with sophisticated masks. Since the amount of dye attached on the polysulfone surface is small, a more sensitive measurement technique based on photon counting was employed for measuring the SHG effect. The SH intensity from the DR1 attached surface is 1.6 to 2.8 times greater than the off-dye region.