Evolution of Nonlinear Optical Characteristics of Magnetic Nanoparticle Colloidal Suspensions after Laser-Induced Clusters

Xiangpeng Yang; Qian Li; Xiangshen Meng; Decai Li

doi:10.1021/acsomega.0c00609

Evolution of Nonlinear Optical Characteristics of Magnetic Nanoparticle Colloidal Suspensions after Laser-Induced Clusters

ACS Omega. 2020 Jun 24;5(26):15821-15827. doi: 10.1021/acsomega.0c00609. eCollection 2020 Jul 7.

Authors

Xiangpeng Yang¹, Qian Li², Xiangshen Meng¹, Decai Li^{1

2}

Affiliations

¹ School of Mechanical, Electronic and Control Engineering, Beijing Jiaotong University, Beijing 100044, P.R. China.
² State Key Laboratory of Tribology, Tsinghua University, Beijing 100084, P.R. China.

Abstract

In this paper, the nonlinear optical properties of magnetic nanoparticle colloidal solutions were studied by the Z-scan technique using 25 ps laser pulses at a wavelength of 1064 nm. Our results reveal that the formed magnetic nanoparticle clusters under high incident laser intensity will greatly affect the nonlinear optical characteristics of the solution. As the intensity of the pulsed laser decreases, the reverse saturable absorption coefficient and nonlinear refractive index of the sample tend to increase. The evolution of this nonlinear characteristic only occurs in liquid suspension. This is confirmed by fixing particles on a substrate upon which the responses observed in the liquid medium are no longer present. Besides, the possibility of generating optical trapping in the focus of the laser pulses is proposed to explain our experimental results.