【摘要】 利用静电自组装技术,以生物大分子材料壳聚糖杂化处理具有稳定结构的CdSe/ZnS核/壳量子点,形成复合多层薄膜.与薄膜的吸收谱线比较,在375nm飞秒激光激发下测量的量子点的光致发光谱存在Stokes位移.采用Z扫描技术,利用790nm飞秒激光研究了其三阶非线性吸收和折射特性,发现饱和吸收信号来自CdSe/ZnS量子点,而自聚焦的折射信号则部分来自壳聚糖.测出多层膜的三阶非线性系数分别是β=6·5×10^-6cm/W,n2=1·5×10^-10cm2/W.更多还原

【Abstract】 Biopolymer_CdSe/ZnS core_shell quantum dot hybrid films were prepared using self_assembly technique. Compared with the absorbance spectrum, the photoluminescence excited by laser with λ=395nm has Stokes shift. The third_order nonlinear optical properties of biopolymer_CdSe/ZnS film were studied by Z_scan setup with femtosecond laser at 790nm. It is found that the nonlinear absorptive signal partially originates from Cde/ZnS quantum dots while the nonlinear refractive signal partially originates from biopolymer chitosan. The magnitudes of them are measured to be β=6.5×10~ -6 cm/W and n_ 2 =1.5×10~ -10 cm~2/W, respectively.更多还原