Waveguide-assisted optical transport of nanoparticles via optical pulling force in 2D photonic crystal

Nanoparticle transportation using wave-guided optical forces in two-dimensional (2D) photonic crystal waveguides offers a promising platform for chip scale optical manipulation. Prior research has shown long range pulling forces by photonic bandgap induced field asymmetry and mode conversion in hollow-core waveguides; however, these methods frequently depend on structural or modal adjustments to produce the pulling effect. Our study illuminates a 2D photonic crystal waveguide driven by a linearly polarized plane wave at 0° incidence, revealing consistent optical pulling forces on both plasmonic (Gold) and dielectric (SiO₂) Rayleigh particles. This phenomena originates solely from the intrinsic interaction between the waveguide and the field, without any external modulation.The periodic architecture of the 2D photonic crystal waveguide generates guided optical modes characterized by spatial asymmetry. This asymmetry results in a directional imbalance in electromagnetic momentum, applying a net strain on adjacent nanoparticles. Utilizing the Minkowski stress tensor, we quantify a continuous tensile force along the waveguide, emerging independently of structural adjustments.These findings demonstrate a simplistic yet effective optical manipulation method, utilizing passive photonic structures for efficient and scalable transport of nanoparticles in integrated photonic systems.