Optical Nonlinearity Of Pbs Nano-materials

In this dissertation, the recent results, analysis methods, and theories of optical nonlinearities of nanometer-sized semiconductor materials were summarized systemically. A kind of sensitive measurement of optical nonlinearities using a single beam Z-scan technique and its theoretical analysis were reviewed in details. Based on Effective Medium Theories (EMT), the third-order nonlinear susceptibility x_eff³ of different shape ofnanometer-sized semiconductor materials were derived. Using Origin Simulation Software, we analysis how shape influence on the third-order nonlinear optical properties and optical limiting (OL) properties.The nonlinear optical properties of different shapes of PbS nanometer-sized materials in diluted DMF suspensions were investigated based on the Z-scan technique using a single beam. It shows that all the three measured samples have strong nonlinear absorption and self-focusing performance in the situation of nanosecond laser pulses incidence, the three-order nonlinear refraction index and nonlinear absorption coefficient and three-order nonlinear susceptibility were calculated. In the situation of picosecond laser pulses incidence, it shows that weak nonlinearities result from the effect of solvent.We also studied the optical limiting properties of different shapes of PbS nanometer-sized materials in diluted DMF suspensions with the wavelength of 532nm, pulse duration of 8ns, repetition frequency of 1 Hz laser pulses, these samples show obvious optical limiting properties. But in the situation of picosecond laser pulses incidence, these samples show weak optical limiting...