K-space polarimetry of bullseye plasmon antennas

Abstract

Surface plasmon resonators can drastically redistribute incident light over different output wave vectors and polarizations. This can lead for instance to sub-diffraction sized nanoapertures in metal films that beam and to nanoparticle antennas that enable efficient conversion of photons between spatial modes, or helicity channels. We present a polarimetric Fourier microscope as a new experimental tool to completely characterize the angle-dependent polarization-resolved scattering of single nanostructures. Polarimetry allows determining the full Stokes parameters from just six Fourier images. The degree of polarization and the polarization ellipse are measured for each scattering direction collected by a high NA objective. We showcase the method on plasmonic bullseye antennas in a metal film, which are known to beam light efficiently. We find rich results for the polarization state of the beamed light, including complete conversion of input polarization from linear to circular and from one helicity to another. In addition to uncovering new physics for plasmonic groove antennas, the described technique projects to have a large impact in nanophotonics, in particular towards the investigation of a broad range of phenomena ranging from photon spin Hall effects, polarization to orbital angular momentum transfer and design of plasmon antennas.

Chirality of Symmetric Resonant Heterostructures

“…We calculate the transmitted angularly resolved Stokes parameters as a function of ‐space coordinates and integrate them over the NA of the incident beam to obtain the averaged output Stokes vector . This method is formally similar to ‐space polarimetry . Importantly, the integration of Stokes parameters is done with respect to the refracted central wavevector in the glass substrate for obliquely incident light and the adapted NA in transmission.…”

“…This method is formally similar to k-space polarimetry. [44,45] Importantly, the integration of Stokes parameters is done with respect to the refracted central wavevector in the glass substrate for obliquely incident light and the adapted NA in transmission. The refraction and scaling of the NA results in the asymmetric integration area in the far-field plane, shown as a compressed circle in the right column of Figure 3.…”

“…To quantify CD and circular birefringence (CB), we adapt the Müller matrix formalism and ‐space polarimetry . We extend this formalism to account for oblique incidence and extrinsically chiral structures.…”

“…To quantify CD and circular birefringence (CB) [40][41][42] , we adapt the Müller matrix formalism [43] and k-space polarimetry. [44,45] We extend this formalism to account for oblique incidence and extrinsically chiral structures. Additionally, motivated by the demonstration of spin-polarized emission of fluorescent molecules and quantum dots coupled to extrinsically chiral nanostructures, [18,22,46] we study the interaction of the heterodimer with linearly polarized light (LP).…”

Broadband light scattering and photoluminescence enhancement from plasmonic Vogel's golden spirals

“…Dark field and Fourier microscopy measurements suggest that the spirals are diffractive structures that consist of essentially uncoupled scatterers. For further confirmation, we perform k-space Stokes polarimetry [18][19][20][21]. Fig.…”