Multiple particles flexible assembly via spatial coherence array engineering

Abstract

Optical tweezer arrays, known for their ability to manipulate microscopic entities in parallel, are widely used to assemble and organize multiple particles or cells. Conventional arrays, constrained by fully coherent beams, suffer from interference between adjacent spots and limited structural flexibility. This study introduces a flexible approach for trapping and manipulating multiple particles using a Laguerre–Gaussian correlated Schell-model beam array, enhanced through spatial coherence array engineering. By precisely tailoring the spatial coherence structure, we achieve highly uniform optical arrays with controllable and adaptable configurations. This method leverages the anti-interference characteristics of partially coherent beams to reduce inter-spot interference, enabling better control over spot spacing and improving precision in particle trapping. The approach is applicable to particles with varying refractive indices under diverse coherence conditions, ensuring reliable control over trapping sites. It also supports parallel manipulation by tuning the spacing of the incoherent source array. Additionally, modulating the radial index further improves configurational flexibility. Notably, the gradient force remains constant during manipulation, ensuring stable particle attachment and preventing trap drift. This stability is attributed to a manipulation strategy that adjusts spot spacing in the spatial coherence array while maintaining constant intensity. Finally, we examine trapping stability and efficiency as functions of coherence width and particle radius and provide preliminary insights into inter-particle interactions. The findings highlight a practical strategy with potential applications in quantum operations, biological systems, and nanomaterial design.