Wavelength‐Scale Spin Hall Shift of Light with Morphology‐Enhanced Scattering Efficiency from Nanoparticles

Abstract

Spin Hall (SH) shift of light from nanoparticles refers to the transverse displacement of scattered light due to spin–orbit interaction (SOI). Generally, the SH shift is small and suffers from inherent low scattering efficiency. In this paper, the SH shift and its corresponding scattering intensity are simultaneously enhanced for dual nanoparticles. Based on the generalized Lorentz‐Mie theory, the morphology of the nanoparticle is optimized to increase the scattering intensity while preserving the wavelength‐scale SH shift. The simultaneous enhancements are realized by manipulating the electric and magnetic dipolar modes to overlap at their resonances rather than the tails of the scattering. Meanwhile, a new pattern is identified on orbital momentum streamlines, revealing the near field's SOI. In addition, an experiment is proposed to detect the SH shifts in the far‐field observation plane. The scattering intensities from oblate spheroids are enhanced by one order of magnitude compared to the spherical counterparts. The findings may shed new light on the mechanism of light–matter interaction and facilitate the experimental detection of the SH effect of light.

Optical Mirages from Spinless Beams

“…According to eq , no apparent shift can emerge for a linearly polarized plane wave impinging on an electric dipolar sphere. The above-mentioned agrees with refs − . Note that similar reasoning can be applied to a pure magnetic dipole.…”

“…All previous results rely on the existence of spin angular momentum in the incident radiation for the optical mirage to be observed. − Moreover, the SOI of light after scattering has been identified as the underlying effect for understanding the physics of optical mirages. Here, we demonstrate that linearly polarized waves (spinless) beams can also give rise to significant optical mirages with magnitudes well beyond the incident wavelength.…”

“…However, these apparent shifts are known to be difficult to measure, requiring quantum weak measurement technology or multiple reflections, among others. 15 In contrast, we should mention that Figure 3a,b can be easily measured (see Supporting Information for further details).…”

“…For microspheres under the illumination of a circularly polarized plane wave, spin-dependent optical mirages reaching tens of wavelengths in magnitude were found . Later on, several groups demonstrated that for high refractive index (HRI) nanospheres under a circularly polarized plane wave illumination, this spin-dependent optical mirage is considerably enhanced. − Beyond the picture of circularly polarized plane waves, optical mirages comparable to the incident wavelength were also found under the illumination of elliptically polarized beams …”

Polarization beam splitting in a Glan-Taylor prism based on dual effects of both birefringence and Goos-Hanchen shift

“…In addition, the different energy band structures of orthogonal polarizations of specific materials could be utilized for PBS [ 2 , 3 ]. Besides, Spin-orbit interaction based Spin Hall Effect of Light (SHEL) [ 4 , 5 , 6 ] and the polarization-dependent Goos-Hanchen (GH) effect [ 7 , 8 ] also exhibits a great potential in PBS.…”