Abstract

The nonlinear absorption of two-dimensional (2 D) Nb2CTx (MXene) nanosheets were investigated by using nanosecond Z-scan measurements in 532 nm under different laser intensities. It was found that, Nb2CTx nanosheets exhibit from saturable absorption (SA) to reverse saturable absorption (RSA). With the increase of incident intensity, a switch from SA to RSA occurs under some excitation intensities. Besides, ultrafast carrier dynamics of Nb2CTx nanosheets were also investigated by using pump-probe technique. It was found that the relaxation contains a biexponential decay process with two decay components, a fast and a slow one. The investigations show that Nb2CTx nanosheets can be used as building ultrashort pulse generation and optoelectronic devices.

摘要

通过在不同激光强度下在 532 nm 处使用纳秒 Z 扫描测量来研究二维 (2 D) Nb2CTx (MXene) 纳米片的非线性吸收。研究发现，Nb2CTx 纳米片表现出从饱和吸收（SA）到反饱和吸收（RSA）。随着入射强度的增加，在一定的激发强度下会发生从 SA 到 RSA 的转换。此外，还使用泵-探针技术研究了 Nb2CTx 纳米片的超快载流子动力学。发现弛豫包含一个双指数衰减过程，该过程具有两个衰减分量，一个快的和一个慢的。研究表明，Nb2CTx 纳米片可用于构建超短脉冲发生和光电器件。