水溶性CdTe:Mn量子点的双光子吸收

采用激发波长800 nm、脉宽50 fs、重复频率1 kHz的Ti:sapphire放大飞秒激光器作为激发光源，利用开孔Z扫描技术研究了不同粒径的CdTe:Mn量子点的非线性吸收性质。理论计算结果表明，同一生长时间CdTe:Mn量子点的双光子吸收系数是CdTe量子点的1.1倍，其双光子吸收系数随量子点尺寸的减小而增大，这是由于CdTe:Mn量子点非线性吸收属于反饱和吸收，掺杂了Mn元素，减小了表面缺陷浓度，表明掺杂量子点具有很好的双光子吸收现象。

Two photon absorption of CdTe:Mn quantum dots in aqueous solution

The two photon absorption of water soluble CdTe quantum dots and Mn2+ doped CdTe quantum dots in four different sizes has been studied, by using the open Z scan technique, with a Ti: sapphire laser at 800 nm wavelength, 50 fs pulsewidth, 1 kHz repetition frequency. The results show that, the two photon absorption coefficient of CdTe: Mn quantum dots is 11 times that of CdTe quantum dots for the same growth time, and the relationship between the two photon absorption coefficient of quantum dots and the particle size is inverse proportion, because the nonlinear absorption of CdTe: Mn quantum dots belongs to the saturated absorption. It is shown that Mn2+ doped quantum dots exhibit good two photon absorption phenomenon, and have broad application prospects in optical switches and optical limiting devices.