The Nonlinear Optical Properties of Poly(m-phenylene diamine)-BaTiO3 Nanocomposite for Laser Application

 Poly(m-phenylenediamine) and barium titanate nanoparticles have promising physical and chemical properties in the electrical and optical fields. One of the attractive properties of these materials is their nonlinear optical behavior. This property allows these materials to be used in high-tech systems, the manufacture of various optical parts as well as lasers.

Poly(m-phenylenediamine/barium titanate) nanoparticles (PmPDA/BaTiO3) nanocomposite was prepared by in situ polymerizations. The prepared materials were characterized by various methods. Nonlinear optical studies of materials were investigated by the Z-scan technique with open aperture and closed aperture to obtain the absorption coefficient and nonlinear refractive index at different concentrations 0.3, 0.5, and 0.7 mg/L with four different intensities at a wavelength of 532 nm.

X-ray diffraction and field emission electron microscopy results showed a semi-crystalline pattern and an irregular aggregate structure for PmPDA/BaTiO3 nanocomposite, respectively. The thermal stability of the nanocomposite increased due to the presence of BaTiO3 nanoparticles relative to PmPDA. The presence of BaTiO3 nanoparticles in the nanocomposite shifted the absorption peak of PmPDA to a shorter wavelength (325 nm). The optical results show that at concentrations of 0.3, 0.5, and 0.7 mg/L with varying intensity of moderate light on PmPDA, BaTiO3, and PmPDA/BaTiO3 samples, the values of nonlinear refractive index (n2) and the nonlinear absorption coefficient (β) are obtained differently. In addition, the results show that by changing the intensity, the samples have a nonlinear refractive index with a negative sign (n2 <0). This result shows that the samples are self-focal in nature and can play an important role in the correction of laser pulses. The samples also have a saturation absorption (SA) nature. This feature plays an important role in the fabrication of optical switches and optical limiters in lasers.