Anapole nanolasers for mode-locking and ultrafast pulse generation

Abstract

Nanophotonics is a rapidly developing field of research with many suggestions for a design of nanoantennas, sensors and miniature metadevices. Despite many proposals for passive nanophotonic devices, the efficient coupling of light to nanoscale optical structures remains a major challenge. In this article, we propose a nanoscale laser based on a tightly confined anapole mode. By harnessing the non-radiating nature of the anapole state, we show how to engineer nanolasers based on InGaAs nanodisks as on-chip sources with unique optical properties. Leveraging on the near-field character of anapole modes, we demonstrate a spontaneously polarized nanolaser able to couple light into waveguide channels with four orders of magnitude intensity than classical nanolasers, as well as the generation of ultrafast (of 100 fs) pulses via spontaneous mode locking of several anapoles. Anapole nanolasers offer an attractive platform for monolithically integrated, silicon photonics sources for advanced and efficient nanoscale circuitry.

The High‐Order Toroidal Moments and Anapole States in All‐Dielectric Photonics

“…After detracing and symmetrization of the primitive Cartesian multipoles, the residual terms form a set of irreducible toroidal moments limited by the toroidal electric octupole and toroidal magnetic quadrupole (Table ). The first order toroidal electric dipole considered previously in a plenty of papers is derived from the decomposition of the primitive electric octupole and the primitive magnetic quadrupole ; the fourth order of the primitive Cartesian multipoles produces two toroidal multipole moments—the toroidal magnetic dipole T ( m ) and the toroidal electric quadrupole (TEQ) , which are obtained from the magnetic octupole and the electric 16‐pole ; the decomposition of the primitive electric 32‐pole and magnetic 16‐pole produces the second contributing term to the full electric dipole moment, the toroidal magnetic quadrupole , and the toroidal electric octupole . The detailed derivation is given in the Supporting Information.…”

Can a Nonradiating Mode Be Externally Excited? Nonscattering States versus Embedded Eigenstates

“…Introduction -The ability to tailor optical scattering in anomalous and extreme ways, beyond what is achievable with conventional optical materials and structures, has been for several years one of the fundamental goals of optical metamaterials and nanophotonic systems [1]. Rapid progress in these fields has enabled the realization of a plethora of anomalous scattering effects, including invisibility [2][3][4][5][6], ultra-sharp Fano scattering resonances [7,8], non-scattering anapole scatterers [9][10][11][12][13][14][15][16], and bound states in the continuum or embedded eigenstates [17][18][19][20][21][22]. Scattering engineering plays a fundamental role in modern photonics research, for applications spanning from wavefront manipulation [23] and optical signal processing [24,25], to energy harvesting [26] and sensing [27], to mention just a few.…”

Near-Field Coupling and Mode Competition in Multiple Anapole Systems

“…Such excitation can be achieved experimentally, as single anapole nanoparticles can be excited by means of a near-field scanning optical microscopy (NSOM) setup [3]. As an appealing alternative, anapole-based waveguides could be combined with integrated nanolasers emitting at the anapole frequency [13]. As the anapole states are tightly confined in the near-field, optical nano-circuitry based on non-radiating modes is extremely robust to bending and splitting, as shown in Figure 5.…”

“…The field enhancement is measured by integrating the electric intensity inside the resonator (Figure 2b, dashed orange line), which exhibits a strong peak at the anapole wavelength λ an . The strong field enhancement associated to the anapole state is a counter-intuitive feature of the non-radiating state, and it has recently been exploited to amplify light-matter processes in semiconductor nanostructures [12,13]. To characterize the mutual coupling between anapole states, we performed a set of simulations for different rotation angles α and distances d, whose results are reported in Figure 1c,d.…”