  Numerical optimization was performed via COMSOL Multiphysics to maximize the
polarization contrast of superconducting nanowire single photon detectors
(SNSPDs). SNSPDs were integrated with four different types of one-dimensional
periodic plasmonic structures capable of mediating p-polarized photon
selectivity to the niobium-nitride superconducting nanowire pattern.
Optimization with two different criteria regarding the maximal tilting resulted
in wavelength-scaled periodic integrated structures, which have different
geometrical parameters, and exhibit different polar angle dependent optical
response and dispersion characteristics, as well as accompanying near-field
phenomena at the extrema. Polarization contrast of 6.37*10^2 and 3.28*10^2 -
6.86*10^11 and 1.42*10^11 - 1.81*10^13 and 7.87*10^12 - 1.90*10^3 and 1.15*10^5
can be achieved in nanocavity-, nanocavity-deflector-,
nanocavity-double-deflector-, nanocavity-trench-array-integrated P-SNSPDs
optimized with 85 degree and 80 degree criterion regarding the maximal tilting.
