[show abstract][hide abstract] ABSTRACT: Nonlinear optical properties of colloidal Au and poly(vinylpyrrolidone) (PVP) composite films were investigated using the Z-scan technique with 25 ps pulses at 532 nm near the surface plasmon resonance frequency of Au nanoparticles. Experimental results show large optical nonlinearities of the composite films with the real and imaginary parts of the third-order nonlinear optical susceptibility χ (3) being 4.7 × 10 −10 esu and 2.5 × 10 −10 esu, respectively. The obtained χ (3) value of Au/PVP composite films is comparable or higher than that of the organometallic complexes reported. Furthermore, a strong optical limiting response was observed and a possible application of the composite films as an optical limiter of picosecond laser pulses was discussed.
Journal of Physics D Applied Physics 01/2006; 39:233-236. · 2.53 Impact Factor
[show abstract][hide abstract] ABSTRACT: Thin films of iron were fabricated on MgO (100) substrates using pulsed laser deposition technique. The crystalline property and surface roughness of the films were investigated by X-ray diffraction and atomic force microscopy, respectively. It was found that the morphology of the Fe film deposited at room temperature was characteristic of continuous metal film. Increasing the deposition temperature caused the smooth Fe film to break up, and nanoscale Fe islands were formed. We performed the z-scan measurements to study the third-order optical nonlinearity of the continuous approximately 9-nm-thick iron film. The results show that the ultrathin iron film exhibits large nonlinear refractive coefficient, n2=7.09×10−5 cm2/kW, and nonlinear absorption coefficient, β=−5.52×10−3 (cm/W), at the wavelength of 532 nm.