Pis’ma v ZhETF, vol. 109, iss. 2, pp. 129 - 130

January 25

Enhanced second-harmonic generation with structured light

in AlGaAs nanoparticles governed by magnetic response

E. V. Melik-Gaykazyan^+∗, K. L. Koshelev^∗×, J.-H. Choi^◦, S. S. Kruk^∗, H.-G. Park^◦, A. A. Fedyanin⁺,

Y. S. Kivshar^∗1)

⁺Faculty of Physics, Lomonosov Moscow State University, 119991 Moscow, Russia

^∗Nonlinear Physics Centre, Australian National University, ACT 2601, Canberra, Australia

^× Information Technologies, Mechanics and Optics University, 197101 St. Petersburg, Russia

^◦Department of Physics, Korea University, 02841 Seoul, Republic of Korea

Submitted 21 November 2018

Resubmitted 21 November 2018

Accepted 23

November 2018

DOI: 10.1134/S0370274X19020127

High-index dielectric nanoparticles can support both

harmonic generation with radially and azimuthally po-

electric and magnetic Mie-type resonances in the visible

larized light [9] and, by tailoring the vectorial structure

and near-infrared spectral ranges [1], and they can easily

of the pumping light, we have demonstrated a control

be tailored by the nanoparticle geometry. The optically-

of both strength and polarization of the excited har-

induced magnetic response of subwavelength dielectric

monic fields, also addressing selectively different types

structures is expected to complement or even replace the

of multipolar Mie resonances.

electric response of plasmonic components for potential

In this Letter, we employ our earlier approach for

applications at the nanoscale. The Mie-resonant silicon

third-harmonic-generation experiments and study, for

nanoparticles have recently received considerable atten-

the first time to our knowledge, nonlinear second-

tion for applications in nanophotonics and metamate-

harmonic (SH) spectroscopy of individual Mie-resonant

rials [1-3] including optical nanoantennas, wavefront-

AlGaAs nanoparticles excited with structured light.

shaping metasurfaces, and nonlinear frequency genera-

Earlier, such problems have been considered only for

tion.

plasmonic nanoparticles and nanoparticle oligomers [8,

In the last few years, the role of nonlinear magnetic

10, 11]. We observe the substantial enhancement of the

response in nanophotonics was intensively addressed. In

SH nonlinear signal generated by an azimuthally polar-

particular, it was demonstrated [4, 5] that the nonlinear

ized (AP) pump beam. We supplement our observations

response from silicon nanodisks prevails over the har-

by numerical mode-decomposion analysis and reveal the

monics generated from the bulk silicon, and it possible

contribution of the modes at the double frequencies, as

to reach conversion efficiency high enough for the gen-

well as confirm that structured light can be employed as

erated visible light to be observed by naked eye. Gener-

an efficient tool for the enhanced harmonic generation

ation of different localized Mie-resonant modes can re-

and subwavelength mode control in nanophotonics.

shape completely the physics of nonlinear effects at the

We choose geometrical parameters of an AlGaAs res-

nanoscale [6]. Generated multipoles are closely related

onator to excite a magnetic multipolar resonance at the

to the vectorial nature of the pump beam, and can be

fundamental wavelength by an AP pump beam in the

distinguished in the far-field region by their polarization

considered spectral range and simulate its linear and

and modal composition [7].

nonlinear optical response, as well as a disk eigenmode

Focused and structured vector beams have already

spectrum using the finite-element method. The height

been employed for the harmonic generation, and they

of a disk is equal to 650 nm, its diameter is 935 nm.

have been used in nanophotonics as a versatile tool,

The azimuthal polarization excites magnetic Mie-type

in comparison with the linearly polarized light, for all-

multipolar modes which is a typical tendency for sub-

optical characterization, particularly, for microscopic

wavelength high-index particles [9, 12, 13]. Contrary to

techniques [8]. Recently, we have studied the third-

the AP excitation, there are not spectral features for the

disk pumped by a radially polarized (RP) vector beam

¹⁾e-mail: ysk@internode.on.net

in the linear regime.

Письма в ЖЭТФ том 109 вып. 1 - 2

2019

129

130

E. V. Melik-Gaykazyan, K. L. Koshelev, J.-H. Choi et al.

Nanoparticles are made of a custom-designed wafer

funding from the Student Mobility Scholarship of the

consisted of GaAs, AlInP and AlGaAs layers by sequen-

President of the Russian Federation, the Russian Min-

tial processes of electron beam lithography, dry etching,

istry of Education and Science (# 14.W03.31.0008), and

selective wet-etching, and pillar dropping down to a slide

the Russian Foundation for Basic Research (the project

glass substrate. We construct a nonlinear spectroscopy

#18-32-01038). Andrey Fedyanin acknowledges the

setup based on an optical parametric amplifier. We im-

support of the Russian Foundation of Basic Research

plement a silicon-based q-plate metasurface [14] to cre-

(project # 18-29-20097) and MSU Quantum Technol-

ate the vectorial structure of a pump beam. A train of

ogy Center. Nonlinear simulations were supported by

wavelength tunable 300-fs laser pulses is focused from

the Russian Science Foundation (# 18-72-10140). Kirill

the front sample side to a beam waist size, which is close

Koshelev acknowledges a support from the Foundation

to a diffraction limit. The SH signal is collected by an

for the Advancement of Theoretical Physics and Math-

objective lens with a numerical aperture 0.9, detected by

ematics “BASIS” (Russia).

a visible CCD camera, and normalized over a spectral

Full text of the paper is published in JETP Letters

function of the setup.

journal. DOI: 10.1134/S0021364019020036

Our experimental results on the SH generation spec-

troscopy of an individual AlGaAs resonator of the

specific geometrical parameters with cylindrical vector

S. Kruk and Yu.S. Kivshar, ACS Photonics 4, 2638

beams are shown in Fig.1. There is the enhancement

(2017).

Y. S. Kivshar, National Science Review 5, 144 (2018).

N. Zheludev and Yu.S. Kivshar, Nature Mater. 11,

917924 (2012).

M. R. Shcherbakov, D. N. Neshev, B. Hopkins,

A. S. Shorokhov, I. Staude, E. V. Melik-Gaykazyan,

M. Decker, A. A. Ezhov, A. E. Miroshnichenko,

I. Brener, A. A. Fedyanin, and Y. S. Kivshar, Nano

Lett. 14, 6488 (2014).

E. V.

Melik-Gaykazyan,

M. R.

Shcherbakov,

A. S. Shorokhov, I. Staude, I. Brener, D.N. Ne-

shev, Yu. S. Kivshar, and A. A. Fedyanin, Phil. Trans.

R. Soc. A 375, 20160281 (2017).

D. Smirnova and Y. S. Kivshar, Optica 3, 1241 (2016).

S. Kruk, R. Camacho-Morales, L. Xu, M. Rahmani,

D. A. Smirnova, L. Wang, H. H. Tan, C. Jagadish,

D. N. Neshev, and Y.S. Kivshar, Nano Lett. 17, 3914

(2017).

Fig. 1. (Color online) Experimental results. Second-

G. Bautista and M. Kauranen, ACS Photonics 3, 1351

harmonic generation spectroscopy of a single Al0.2Ga0.8As

(2016).

resonator with a diameter of 935 nm pumped by struc-

E. V. Melik-Gaykazyan, S. S. Kruk, R. Camacho-

tured light. Blue dotes correspond to the azimuthally po-

Morales, L. Xu, M. Rahmani, K. Zangeneh Kamali,

larized pump; red dots - to the radially polarized light, as

A. Lamprianidis, A. E. Miroshnichenko, A. A. Fedyanin,

shown in the inset. White arrows illustrate the polariza-

D. N. Neshev, and Y. S. Kivshar, ACS Photonics 5, 728

tion distributions in the central cross-section of cylindrical

(2018).

vector pump beams

10.

A. Ahmadivand, R. Sinha, and N. Pala, Optics & Laser

Technology 90, 65 (2017).

of the SH signal for the case of a particle which is res-

11.

G. Bautista, C. Dreser, X. Zhang, D. P. Kern, M. Kau-

onant at the fundamental wavelength and pumped by

ranen, and M. Fleischer, Nano Lett. 18, 2571 (2018).

AP laser light. The additional local peaks of the ex-

12.

T. Das, P. P. Iyer, R. A. DeCrescent, and J. A. Schuller,

perimental SH spectrum are associated with the exci-

Phys. Rev. B 92, 241110 (2015).

tation of disk eigenmodes at the SH wavelengths. We

13.

T. Das and J. A. Schuller, Phys. Rev. B 95, 201111

observed the four-time less enhancement of the nonlin-

(2017).

ear response provided by a non-resonant in the linear

14.

S. Kruk, B. Hopkins, I. I. Kravchenko, A. Mirosh-

regime particle excited by a RP laser beam.

nichenko, D. N. Neshev, and Y. S. Kivshar, APL Pho-

The authors thank Prof. Barry Luther-Davies for

tonics 1, 030801 (2016).

support. Elizaveta Melik-Gaykazyan acknowledges the

Письма в ЖЭТФ том 109 вып. 1 - 2

2019