Insights into the generation of laser-induced assembly of MoSe₂ nanospheres

Laser-induced assembly is a promising technology for advancing micro/nano photonic devices. However, the dynamic process and the photothermal interaction in laser-induced assembly technique, as well as the role of laser illumination pattern on the assembly structure have not been well investigated. In this paper, we prepare dark MoSe₂ nanospheres with a facile solvothermal synthesis method and grow a concentric ring-shaped assembly with incident light following Fresnel circular-aperture diffraction. The impact of the illumination light filed on the structure of the assembly is investigated. The concentric ring-shaped assembly reveals focusing effect with about 4.87 times intensity amplification. Optical trap effect, photothermal effect, and tension effect are proved to synergistically enhance the trap stiffness and broaden trap region. This work gives an insight into the production of laser induced assembly, hence broadens the potential application of nanoparticles and assembly in micro-optics and photonic devices.