Polarization Independent High Absorption Efficiency Single-Photon Detectors Based on Three-Dimensional Integrated Superconducting And Plasmonic Patterns

Three-dimensional superconducting nanowire single-photon detectors (SNSPDs) composed of two-dimensional plasmonic gratings integrated into two one-dimensional periodic and vertically shifted patterns of absorbing niobium-nitride nanowires were optimized numerically. Their potential to achieve high infrared absorptance polarization independently was proven. Advantages of vertical-wall, tilted-wall and in-substrate deepening gold antenna segments were compared. The highest ~93% polarization independent absorptance maximum was achieved exactly at the desired 1550 nm in nano-cavity-double-deflector grating integrated SNSPDs with 1.003 (0.997) polarization contrast at perpendicular incidence in 0° (90°) azimuthal orientation. This device exhibits the smallest polarization dependence throughout the complete azimuthal angle and the inspected wavelength intervals.