We demonstrate the first photonic spin-meron tube lattice in free space using spin-angular momentum vectors. Non-paraxial spin–orbit coupling forms finite-length meron tubes (N_sk ≈±1/2), whose length is dependent on diffractive element dimensions. We also show that C₃ geometry of triangular block yields spin-skyrmion tube while effective Moir´e bilayer results in spin-twistronics in free space without the need of strong near field confinement.

We experimentally phase-matched the second-harmonic generation (SHG) between two orthogonal modes. Accurate design of plasmonic two-wire transmission-line (TWTL) greatly raised the conversion efficiency to 0.021% and simultaneously extended the operational length to 18 um. A multi-stage device is capable of performing polarization-dependent switching between the linear propagation of SHG and frequency up-conversion in the later stages. We further realize a nonlinear OR logic operation.

https://doi.org/10.1002/adom.202503409

We integrate monolayer MoSe₂ with a plasmonic nanocircuit and demonstrate the coherent selective routing of the enhanced nonlinear optical signal emitted by the 2D semiconductor, with routing extinction ratios up to 14.86 dB.

https://doi.org/10.1038/s41467-024-46209-8