Polar-azimuthal angle dependent efficiency of different infrared superconducting nanowire single-photon detector designs
Author(s)Csete, Maria; Sipos, Aron; Najafi, Faraz; Berggren, Karl K.
MetadataShow full item record
The illumination-angle-dependent absorptance was determined for three types of superconducting-nanowire singlephoton detector (SNSPD) designs: 1. periodic bare niobium-nitride (NbN) stripes with dimensions of conventional SNSPDs, 2. the same NbN patterns integrated with ~quarter-wavelength hydrogensilsesquioxane-filled nano- cavity, 3. similar cavity-integrated structures covered by a thin gold reflector. A three-dimensional finite-element method was applied to determine the optical response and near-field distribution as a function of p-polarized light illumination orientations specified by polar-angle, φ, and azimuthal-angle, γ. The numerical results proved that the NbN absorptance might be maximized via simultaneous optimization of the polar and azimuthal illumination angles. Complementary transfer-matrix-method calculations were performed on analogous film-stacks to uncover the phenomena contributing to the appearance of extrema on the optical response of NbN-patterns in P-structure-configuration. This comparative study showed that the absorptance of bare NbN patterns is zero at the angle corresponding to total internal reflection (TIR). In cavity-integrated structures the NbN absorptance curve indicates a maximum at the same orientation due to the phase shift introduced by the quarter-wavelength HSQ layer. The reflector promotes the NbN absorptance at small polar angles, but the available absorptance is limited by attenuated TIR in polar angle-intervals, where surface modes are excited on the gold film.
DepartmentMassachusetts Institute of Technology. Research Laboratory of Electronics
Infrared sensors, devices, and applications : and Single photon imaging II
Society of Photo-optical Instrumentation Engineers
Csete, Maria et al. “Polar-azimuthal Angle Dependent Efficiency of Different Infrared Superconducting Nanowire Single-photon Detector Designs.” Infrared sensors, devices, and applications: and Single photon imaging II : 22-25 August 2011, San Diego, California, United States. Edited by Paul D. LeVan et al. 2011. 81551K–81551K–8. (Proceedings of SPIE ; v. 8155) Web. ©2011 SPIE.
Final published version
SPIE v. 8155