碳纳米点的制备及其非线性光限幅性能研究

Preparation and nonlinear optical limiting properties of carbon nanodots

以肝素钠为碳源,通过水热合成法制备碳纳米点(CNDs),对所制得的CNDs形貌、组成及线性光学性能进行系统研究。结果表明,CNDs粒径均一,且表面富含羧基和羟基等官能团;在270 nm处有明显的紫外吸收峰。CNDs具有与激发波长相关的荧光特性,发射峰随激发波长增大的而红移。采用开孔Z-扫描法探索CNDs的非线性光学效应,结果表明,CNDs具有与能量相关的从饱和吸收向反饱和吸收转变的特性,其非线性吸收系数β和饱和能量I_S分别为1.4×10^(-11)m/W和8×10^(10)W/m^2。

Carbon nanodots（CNDs） were synthesized by a simple method of hydrothermal carbonization,using sodium heparin as carbon source. The morphology,structure and linear optical properties of the CNDs were investigated. The surface of the CNDs with uniform size is rich in carboxyl and hydroxyl groups. The CNDs show an obvious ultraviolet absorption peak at 270 nm in the UV/Vis spectra. The CNDs have strong fluorescence properties related to excitation wavelengths,and the emission peak shifts with the increase of the excitation wavelengths. Open-aperture Z-scan technique was used to explore the nonlinear optical effects of the CNDs. The transformation from saturation absorption to reverse saturation absorption in the CNDs suspension was observed with the increase of the input light intensity. The nonlinear absorption coefficient β and the saturation energy ISwere calculated to be 1.4×10^（-11）m/W and 8×10^（10）W/m^2 respectively.