Real and imaginary components of the third-order nonlinearity of polyaniline dodecylbenzenesulfonic salt

Synthesis, Surface Morphology, Gas Sensor, DSC Technique and Third-Order Behavior of Conducting Polymer

The compound polyaniline (Poly-ANI) with different concentrations of (H2SO4) sulfuric acid has been synthesized by the chemical polymerization method. The prepared compounds have been characterized using number of techniques including FTIR, FE-SEM, EDS and DSC. Additionally, UV-Vis spectroscopy employed for studying the linear optical properties of polymer with different acid concentrations. Third order optical nonlinearity was characterized using Z-scan at 532 nm. The results showed that the nonlinear refractive index has a negative sign. It was observed that the nonlinear refractive index changes in different ratios of H2SO4. The high value of nonlinear refractive index ([Formula: see text]) obtained along Z-axis is [Formula: see text] cm2/W, and the corresponding [Formula: see text] is 21.5 × 10-5 esu. Also, the Poly-ANI film shows the response to NH3 gas sensing in the range 20 ppm-250 ppm and can be used for NH3 sensing application.

Saturable absorption in poly(indenofluorene): a picket-fence polymer

Poly(indenofluorene) shows a strong degenerate four-wave mixing (DFWM) response when it is excited with 100-fs pulses at 800 nm. The DFWM signal scales with the 1.5 power of the input intensity, which we interpret as being due to absorption saturation phenomena. The saturation was studied by open-aperture Z scan in dilute solutions of poly(indenofluorene) in chloroform. The changes in the absorption coefficient alpha are described by the formula alpha = alpha(0)/[1 + (I/I(sat))(1/2)], where I(sat) is the saturation intensity, which is found to be of the order of 100>MW/cm(2).

Two-dimensional bright spatial solitons stable over limited intensities and ring formation in polydiacetylene para-toluene sulfonate

Spatial soliton formation in the bulk single-crystal polydiacetylene para-toulene sulfonate has been studied experimentally. The unique nonlinearity of this material at 1600 nm leads to stable solitons below an intensity maximum, and for higher intensities the input beams form a ring and a soliton.

Two-photon saturation in the band gap of a molecular quantum wire

The saturation of the strongest two-photon band accessible with photon energies in the band gap of a onedimensional pi-electron conjugated molecular single crystal is observed with 200-fs pulses for optical intensities of the order of 2 GW/cm(2).