On-Chip Optimal Stokes Nanopolarimetry Based on Spin–Orbit Interaction of Light

Abstract

Full measurement of the polarization of light at the nanoscale is expected to be crucial in many scientific and technological disciplines. Ideally, such measurements will require miniaturized Stokes polarimeters able to determine polarization nondestructively, locally, and in real time. For maximum robustness in measurement, the polarimeters should also operate optimally. Recent approaches making use of plasmonic nanostructures or metasurfaces are not able to fulfill all these requirements simultaneously. Here, we propose and demonstrate a method for subwavelength-footprint Stokes nanopolarimetry based on spin-orbit interaction of light. The method, which basically consists on a subwavelength scatterer coupled to a (set of) multimode waveguide(s), can fully determine the state of polarization satisfying all the previous features. Remarkably, the nanopolarimetry technique can operate optimally (we design a nanopolarimeter whose polarization basis spans 99.7% of the maximum tetrahedron volume inside the Poincaré sphere) over a broad bandwidth. Although here experimentally demonstrated on a silicon chip at telecom wavelengths, spin-orbit interaction-based nanopolarimetry is a universal concept to be applied in any wavelength regime or technological platform.

Unidirectional evanescent-wave coupling from circularly polarized electric and magnetic dipoles: An angular spectrum approach

“…SOI effects are generally believed to be small unless enhanced with artificial materials [20,21]. However, in the present case, illuminated particles scatter light into completely opposite directions, constituting a remarkably simple yet drastic example of SOI, providing a unique opportunity for robust, integrated, ultrafast light nanorouting based on polarization [15,[22][23][24][25]. The effect can also have important consequences in the optical manipulation of chiral [26,27] and nonchiral nanoparticles [28][29][30][31], giving rise to unintuitive lateral forces, as well as applications in optical isolation [13,32].…”

Chiral excitation of spin waves in ferromagnetic films by magnetic nanowire gratings

“…[60]]. Nonetheless of this and other differences, the application perspective of the chiral coupling found in plasmonics such as broadband optical nanorouting [60,61] and polarization analyzers [62] should stimulate similar activities in magnonics.…”

Evanescent gravitational waves

“…In nanophotonics, evanescent waves play a dominant role [1]. Recent awareness of their interesting properties has spurred huge interest: evanescent fields were recently found to have a transverse spin [2][3][4][5], and to exhibit spin-momentum locking [6][7][8][9], leading to a myriad of practical applications in light nano-routing, quantum optics, nonreciprocal devices, optical forces and polarimetry [10][11][12][13][14][15][16][17]. Beyond electromagnetism, evanescent waves have now been found to exhibit analogous properties in other wave fields, such as acoustics [18][19][20].…”