Sub-wavelength photonic hooks generated in photonic chips with asymmetric array of Si3N4 micropillars

Photonic hooks, akin to curved photonic nanojets, result from introducing asymmetry in refractive index distribution, achieved by using asymmetric particles or masking the illumination path. These structures function similarly to Airy beams, enabling particle manipulation and imaging. We propose a planar photonic chip design generating subwavelength-width photonic hooks. Illuminating three Si₃N₄micro-pillars with a 532 nm TE polarized plane wave—comprising one λ-wide and two λ/3-wide—produces intense photonic hooks above the micro-pillars, with a 0.7 λ FWHM. The larger pillar, separated by 2λ from the smaller ones, which are λ/3 apart, influences hook properties and optical forces. This offers potential advancements in nanophotonics and microfluidic systems integration.