Investigations on the optical forces from three mainstream optical resonances in all-dielectric nanostructure arrays

• Guangdong Wang and
• Zhanghua Han

Beilstein J. Nanotechnol. 2023, 14, 674–682, doi:10.3762/bjnano.14.53

• manipulation of nanoparticles by optical forces. It is important to use low-power lasers to achieve efficient trapping and avoid any harmful heating effects. Keywords: all-dielectric nanostructures; anapole; optical force; quasi-bound states in the continuum; toroidal dipole; Introduction Optical forces have

• may generate a detrimental effect to the captured particles. In this context, all-dielectric nanostructures made from lossless materials are preferable to be used. With the possibility to support various types of electromagnetic resonances (e.g., toroidal dipole (TD), anapole, or bound state in the

• interact directly with electromagnetic waves and is often masked by electric dipoles (EDs) or magnetic dipoles (MDs) with stronger responses. However, the TD has a unique current distribution, which can generate a strong near-field localization effect, so it has broad application scenarios [8]. The anapole

Optically and electrically driven nanoantennas

• Monika Fleischer,
• Dai Zhang and
• Alfred J. Meixner

Beilstein J. Nanotechnol. 2020, 11, 1542–1545, doi:10.3762/bjnano.11.136

• boosted by forming a hybrid antenna. In the case of [55] an AlGaAs nanopillar, which has an anapole mode resonant with the pump wavelength, is encompassed by a gold ring. The field enhancement by the plasmonic structure is shown to lead to almost two orders of magnitude improvement of the SHG and a

Metal–dielectric hybrid nanoantennas for efficient frequency conversion at the anapole mode

• Valerio F. Gili,
• Lavinia Ghirardini,
• Davide Rocco,
• Giuseppe Marino,
• Ivan Favero,
• Iännis Roland,
• Giovanni Pellegrini,
• Lamberto Duò,
• Marco Finazzi,
• Luca Carletti,
• Andrea Locatelli,
• Aristide Lemaître,
• Dragomir Neshev,
• Costantino De Angelis,
• Giuseppe Leo and
• Michele Celebrano

Beilstein J. Nanotechnol. 2018, 9, 2306–2314, doi:10.3762/bjnano.9.215

• spectrum. In this frame, AlGaAs nanoantennas demonstrated to be extremely efficient sources of second harmonic radiation. In particular, the nonlinear polarization of an optical system pumped at the anapole mode can be potentially boosted, due to both the strong dip in the scattering spectrum and the near

• to the nanopillar at coincidence with the anapole mode, hence boosting both second- and third-harmonic generation conversion efficiencies. More than one order of magnitude enhancement factors are measured for both processes with respect to the isolated structure. Conclusion: The present results

• reveal the possibility to achieve tuneable metamixers and higher resolution in nonlinear sensing and spectroscopy, by means of improved both pump coupling and emission efficiency due to the excitation of the anapole mode enhanced by the plasmonic nanoantenna. Keywords: nanophotonics; nonlinear optics

Excitation of nonradiating magnetic anapole states with azimuthally polarized vector beams

• Aristeidis G. Lamprianidis and
• Andrey E. Miroshnichenko

Beilstein J. Nanotechnol. 2018, 9, 1478–1490, doi:10.3762/bjnano.9.139

• nonradiating modes, called “anapoles”. Here we study theoretically the excitation of such exotic anapole modes in silicon nanoparticles using structured light. Alternative illumination configurations, properly designed, are able to unlock hidden behavior of scatterers. Particularly, azimuthally polarized

• focused beams enable us to excite ideal anapole modes of magnetic type in dielectric nanoparticles. Firstly, we perform the decomposition of this type of excitation into its multipolar content and then we employ the T-matrix method to calculate the far-field scattering properties of nanoparticles

• illuminated by such beams. We propose several configuration schemes where magnetic anapole modes of simple or hybrid nature can be detected in silicon nanospheres, nanodisks and nanopillars. Keywords: anapole excitation; dielectric nano-optics; multipolar expansion; T-matrix method; vector beams