Compact TM-pass polarizer based on a slot-assisted hollow hybrid plasmonic waveguide.

Addressing the urgent demand for high-performance polarization control in silicon photonics, this work presents a compact TM-pass polarizer based on a synergistic vertical air slot and hollow hybrid plasmonic waveguide (HPW). The hollow HPW provides strong light-field localization, while the vertical air slot enables polarization-selective modulation. The hollow HPW enables strong TM mode localization, while the air slot selectively suppresses the TE mode through polarization-dependent cutoff. Optimized adiabatic mode transition minimizes TM propagation loss, while flexible polarization-region length adjustment enables broad-range selectivity for diverse applications. Compared to existing designs, it offers a 42% length reduction in its most compact form (5.8 µm), featuring a 214% bandwidth extension and 10% lower loss and with a polarization extinction ratio of 30.64 dB and an insertion loss of 0.4 dB at a 1.55 µm operating wavelength with a device length of 11.8 µm, integrating compactness with broad spectral performance.