Optimized Superconducting Nanowire Single Photon Detectors to Maximize Absorptance

Dispersion characteristics of four types of superconducting nanowire single photon detectors, nano-cavity-array-(NCA-), nano-cavity-deflector-array-(NCDA-), nano-cavity-double-deflectorarray-(NCDDA-) and nano-cavity-trench-array-(NCTA-) integrated (A-SNSPD) devices were optimized in three periodicity intervals commensurate with half-, three-quarterand one surface plasmon polariton wavelength. The optimal configurations capable of maximizing absorptance in niobium nitride correspond to periodicity-dependent tilting in S-orientation (90◦ azimuthal orientation). In NCAI-A-SNSPDs absorptance maxima are reached at the plasmonic Brewster angle due to light tunneling. The absorptance maximum is attained in a wide plasmonic-pass-band in NCDAI1/2∗λ-A, inside a flat-plasmonicpass-band in NCDAI3/4∗λ-A and inside a narrower plasmonic-band in NCDAIλ-A. In NCDDAI1/2∗λA bands of strongly-coupled cavity and propagating plasmonic modes cross, in NCDDAI3/4∗λ-A an inverted-plasmonic-band-gap develops, while in NCDDAIλ-A a narrow plasmonic-pass-band appears inside an inverted-minigap. The absorptance maximum is achieved in NCTAI1/2∗λ-A inside a plasmonicpass-band, in NCTAI3/4∗λ-A at an inverted-plasmonic-band-gap center, while in NCTAIλ-A inside an inverted-minigap. The highest 95.05% absorptance is attained at perpendicular incidence onto NCTAIλA. Quarter-wavelength type cavity modes contribute to the near-field enhancement around NbN segments except in NCDAIλ-A and NCDDAI3/4∗λ-A. The polarization contrast is moderate in NCAI-ASNSPDs (∼ 102). NCDAIand NCDDAI-A-SNSPDs make possible to attain considerably large polarization contrast (∼ 102 − 103 and ∼ 103 − 104), while NCTAI-A-SNSPDs exhibit a weak polarization selectivity (∼ 10 − 102).