Angle-suppressed scattering and optical forces on submicrometer dielectric particles

Abstract

We show that submicrometer silicon spheres, whose polarizabilities are completely given by their two first Mie coefficients, are an excellent laboratory to test effects of both angle-suppressed and resonant differential scattering cross sections. Specifically, outstanding scattering angular distributions, with zero forward- or backward-scattered intensity, (i.e., the so-called Kerker conditions), previously discussed for hypothetical magnetodielectric particles, are now observed for those Si objects in the near infrared. Interesting new consequences for the corresponding optical forces are derived from the interplay, both in and out of resonance, between the electric- and magnetic-induced dipoles.

Magnetic and electric coherence in forward- and back-scattered electromagnetic waves by a single dielectric subwavelength sphere

“…These are reminiscences of electric and magnetic whispering gallery modes. On resorting to the theory on magnetodielectric spheres reported in our previous work 25,26,39 , and that on Si and ceramic cylinders 28 , and recalling the scaling ratio l/(na) that maintains the existence of these phenomena in different frequency ranges, we also predict similar observations in conventional semiconductor spheres in the nearinfrared. The rescaling property of our scattering problem, together with the intrinsic interest that our results have in technological applications in the microwave range (electrically small antennas) aimed us to perform our simulations and experiments in the microwave regime (vB3-9 GHz-lB33-100 mm) 15 .…”

“…4b). In contrast with the previous case, an exact zero-forward scattering cannot be obtained due to energy conservation constraints 15,39,44 . However, most of the scattered energy is located in the backward hemisphere with a 73% versus a 27% in the forward hemisphere.…”

Directional visible light scattering by silicon nanoparticles

“…Scattering anisotropy described above has recently been discussed theoretically for silicon 27 and germanium 28 nanoparticles. In particular, it was shown that the wavelengths of the maximum forward and backward scattering correspond well to conditions derived by Kerker et al for hypothetic magnetodielectric particles 29 .…”

“…On the other hand, as shown in recent theoretical works, interference of magnetic and electric dipole resonances inside high-refractive index dielectric nanoparticles can strongly affect their scattering pattern making it dependent on wavelength 27,28 . For some wavelengths the particles can act as 'Huygens' sources, scattering the whole energy in the forward direction, while for another wavelength range, light is almost completely scattered backward.…”

Electromagnetic energy and negative asymmetry parameters in coated magneto-optical cylinders: Applications to tunable light transport in disordered systems

“…However, efforts have been made to propose and design metamaterials that support both electric and magnetic dipolar resonances, such as spheres [13,16] and high permittivity cylinders [14]. These efforts have allowed the achievement of zero-backward scattering and near-zero-forward scattering conditions (known as Kerker conditions), first * tiagoarruda@pg.ffclrp.usp.br theoretically predicted for hypothetical particles exhibiting both electric and magnetic dipolar resonances [17], and highly directional EM scattering [18][19][20][21][22][23]. The observation of Kerker conditions relies on the interference of electric and magnetic dipoles in nanostructures [24,25].…”