DR ANDREY MIROSHNICHENKO
Manipulating light
Dr Andrey Miroshnichenko is working to control light at the subwavelength scale. In this interview, he
details the many and varied applications of these nanodevices and his vision for future communications
Can you explain what nanophotonics is and
the significance of this budding field?
Nanophotonics offers opportunities for studying
the interaction between light and matter on
a scale much smaller than the wavelength of
radiation, as well as for the design of novel
nanostructural optical materials and devices.
Furthermore, the use of such a confined
interaction to spatially localise photochemical
processes offers exciting opportunities for
nanofabrication. It also has important biomedical
applications in bioimaging, optical diagnostics
and photodynamic therapy.
To begin, could you provide a synopsis
of your research background and outline
your key objectives?
The main focus of my research is nonlinear
optics and nanophotonics, with an emphasis
on the study of the resonant light-matter
interaction. Over the past ten years, I
have made contributions to the field of
optical Fano resonances, resonant light
scattering by nanoparticles and lightinduced effects in liquid crystals. One of my
key objectives is the development of new
methods and approaches for the effective
control and routing of optical signals at
the subwavelength scale, facilitating the
emergence of novel technologies.
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INTERNATIONAL INNOVATION
By targeting the control of light at the
nanoscale, how do you envisage your
research impacting future applications?
The intelligent use of light may lead to
a number of novel devices, ranging from
laser chips and optical sensors to all-optical
communication systems for high-speed
computing and data transfer. For example, the
resonant interaction of light with plasmonic
nanoparticles allows us to squeeze light into
the subwavelength scale. Estimates suggest
that the energy density of a photon squeezed
into a 1 nm volume is a billion times larger
than that of the Sun, which produces a
massive enhancement of electromagnetic
fields by concentrating the energy into
nanoscale volumes. It paves the way for
novel applications in the fields of near-field
microscopy, high-resolution biomedical
sensors, efficient solar cells, ultra-fast optical
communication, data storage and many others.
How can resonances in semiconductor
nanostructures be exploited to boost the
performance of photonic devices?
According to theoretical predictions based
on Mie theory, spherical high-refractive index
dielectric nanoparticles (largely comprised
of semiconductor materials, such as silicon
and germanium) can have strong electric and
magnetic dipole-like resonances in the visible
spectral range. The magnetic dipole response
of dielectric nanoparticles originates from the
circular displacement currents excited inside the
particle by incident light. It enables the control of
the magnetic resonance wavelengths with particle
size, which are directly proportional. Moreover,
the relative strengths of electric and magnetic
responses can be changed independently by
varying the shape of a nanoparticle. It provides
the ability to tune the optical properties of a
single element with great flexibility, which can
be employed in a number of applications, such as
optical nanoantennas.
In regard to their current development,
could you provide an insight into optical
nanoantennas?
Light control at the nanoscale is critical
to future on-chip integration. At the
DR ANDREY MIROSHNICHENKO
A new frontier
in nanophotonics
Research at the Australian National
University is underpinning new
approaches to nanoscale photonic
devices. This work is facilitating
innovative forms of nanoscale
interaction, with applications in
computing and medicine
subwavelength scale, conventional optical
elements become unsuitable, and optical
nanoantennas (antennas for light) offer a
new approach to the design of nanoscale
photonic devices. Optical nanoantennas can
manipulate light emission from quantum
emitters or nanolasers, and provide links
between localised light and free-space
propagating radiation.
The study of nanoantennas is a rapidly
growing area, and nanoantennas of various
geometries have been demonstrated for
non-classical light emission, fluorescence
enhancement, high-harmonic generation,
nanoscale photodetectors and singlemolecule detection. Considering the fact that
optical nanoantennas are fabricated using
nanosphere lithography, there is potential for
the cost-effective and large-area fabrication
of nanoscale structures.
Similar to electronics in the 20th Century,
do you believe photonics has the potential
to revolutionise communications
technology in the 21st Century?
Absolutely – I strongly believe that the 21st
Century belongs to photonics. Harnessing
light is the key to life changing technologies,
from energy to communication, from
biotechnologies to low-cost precision
manufacturing, from high-speed internet
to quantum-level information processing.
Many important industries, including chip
manufacturing and lighting, healthcare
and life sciences, space, defence and the
automotive sectors, rely on the same
fundamental mastery of light. Future
technologies will push for a steep increase in
photonic integration and energy efficiency, far
exceeding that of bulk optical components,
current silicon photonics and even innovative
plasmonic circuits.
THE BEHAVIOUR OF light has fascinated
humankind for centuries, and controlling
light underlies many powerful technologies.
More recently, the intelligent use of light has
generated high-performance optical devices,
including optical communication systems for
high-speed computing. Today, we can study light
at the nanometre scale – this is nanophotonics.
The developing field integrates photonics with
nanotechnology and has made huge progress
in recent years based on technology that allows
researchers to investigate the properties of
materials with almost atomic level resolution.
Cutting-edge nanotechnology allows scientists
to create nanoscale structures that can
manipulate the interaction between light and
matter in ways, and at scales, never before
possible. This has consequently opened the
doors to nanofabrication and new applications
in computing, such as data storage, and even
optical diagnostics in biomedicine.
In recognition of its huge potential, the field is
accelerating rapidly. Dr Andrey Miroshnichenko,
Australian Research Council (ARC) Future Fellow
at the Nonlinear Physics Centre of the Australian
National University, is making important
contributions to this. He is leading the ‘Resonant
Nanophotonics: tailoring resonant interaction of
light with nanoclusters’ research programme to
explore the opportunities derived from recent
advances in fabrication technologies, studying
the fundamentals of resonant light-matter
interaction as well as the practical applications
of photonic nanostructures.
A UNIQUE FORM OF RESONANCE
Miroshnichenko’s approach is focused on
resonant nanostructures. Resonance describes
the tendency of a physical system to oscillate
with greater amplitude at some frequencies than
others. Pushing a child on a swing is a common
example: the loaded swing (a pendulum) has a
natural frequency of oscillation – its resonant
frequency – and resists being pushed to go any
faster or any slower. Resonance is ubiquitous
in nature; light is produced by resonance on an
atomic scale and by using optically resonant
Schematic illustration of optically-induced magnetic
dipole response of subwavelength silicon nanoparticles in
the visible spectrum. The enhanced magnetic response (B)
originates via resonant excitation of circular displacement
currents (E) inside the dielectric nanoparticle.
nanostructures, Miroshnichenko hopes to
enhance the interaction of light with matter.
Within this, the project is particularly focused
on Fano resonance. This form of resonance
is characterised by its unique asymmetric
profile comprising both suppression and
enhancement of the scattering, due to
resonant interference phenomena. It is found in
plasmonic nanoparticles, photonic crystals and
electromagnetic metamaterials, and its steep
dispersion profile shows promise for sensors,
lasers and nonlinear slow-light devices.
ASYMMETRICAL SCATTERING
Nanoscale resonators are the building blocks
of many multi-dimensional structures. New
emphasis has been placed on the optical
properties of metallic nanoparticles, due to
their ability to squeeze light into nanometre
dimensions. At this scale, electromagnetic
excitations show strong local enhancement.
However, it has recently been suggested that
light scattering by nanoparticles with low
dissipation rates, such as potassium, exhibit
surprising features.
Building on this, Miroshnichenko showed
that this unusual scattering is similar to Fano
resonance. A slight variation in incident light
frequency in the vicinity of the resonance
drastically changes the scattering pattern,
leading to Fano-like profiles.
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INTELLIGENCE
RESONANT NANOSTRUCTURES
– BOOSTING LIGHT-MATTER
INTERACTION WITH MAGNETIC LIGHT
OBJECTIVE
To develop new methods and approaches
for effective control and routing of
optical signals at the subwavelength
scale, facilitating the emergence of novel
technologies.
KEY INTERNATIONAL
COLLABORATORS
Professor Boris Lukyanchuk, Data Storage
Institute, Singapore
Professor Stefan Maier, Imperial College
London, UK
Dr Pavel Belov, St Petersburg National
Research University of Information
Technologies, Mechanics & Optics
(ITMO), Russia
FUNDING
Australian Research Council (ARC)
CONTACT
Dr Andrey Miroshnichenko
ARC Future Fellow
Nonlinear Physics Centre
Research School of Physics and Engineering
Australian National University
Canberra
Australian Capital Territory 0200
Australia
T +61 2 6125 3964
E [email protected]
www.anu.edu.au
ANDREY MIROSHNICHENKO
obtained his PhD in 2003 from the MaxPlanck Institute for Physics of Complex
Systems in Dresden, Germany. In 2004
he joined the Nonlinear Physics Centre
at the Australian National University.
Since then, Miroshnichenko has made
fundamentally important contributions
to the field of nanophotonics, which have
been recently acknowledged by a Future
Fellowship award from the ARC. The
current topics of his research are nonlinear
nanophotonics and resonant interaction of
light with nanoclusters, including optical
nanoantennas and metamaterials.
ENHANCED MATERIALS
Miroshnichenko aims to elucidate the unique
properties of resonant light-matter interaction
at the nanoscale – from single nanoparticles to
complex structures and nanocircuits – with a view
to controlling light propagation and localisation at
the subwavelength scale, and is working to achieve
this through three key areas. The first of these is
based on resonant light-matter interactions, where
he is studying physical effects in nanostructured
materials. Based on his findings, Miroshnichenko is
developing pioneering approaches to enhance the
electrical field and tailor the resonance response at
different scales.
The second key aspect of the project is the
optical magnetic response of nanoparticles,
crucial to the development of metamaterials
(materials with properties not found in nature)
in the visible range. Today, all structures with
artificial magnetism contain metallic elements,
which suffer high conduction losses at optical
frequencies. To overcome these performance
losses, Miroshnichenko is using high-permittivity
dielectric nanoparticles, which elicit a magnetic
response to light in the visible range. Combining
silicon nanoparticles of different radii or shapes to
overlay magnetic and dielectric resonant responses
at the same frequency, he was able to create a truly
innovative all dielectric, optical, 3D metamaterial.
Photonic structures composed of dielectric
resonators can exhibit many of the same features
as plasmonic nanostructures including enhanced
scattering, high-frequency magnetism and negative
refractive index. Very recently, Miroshnichenko
revealed the inherent principles of the specific
design and parameter engineering of all-dielectric
nanoantennas giving rise to superior performance in
comparison with their plasmonic counterparts. As
such, dielectric resonators and novel all-dielectric
metamaterials represent a potential replacement
for plasmonic structures in applications where loss
is a detrimental factor.
NOVEL BUILDING BLOCKS
Ultimately, Miroshnichenko hopes this project will
enable him to develop groundbreaking methods
for the effective subwavelength control of light.
Through the advancement of knowledge in this
emerging field, the project will facilitate progress in
high-speed computing – allowing the integration of
photonic and electronic components in functional,
on-chip devices. Moreover, creating nanostructures
that are extremely sensitive to light, and the
surrounding environment, will benefit biosensing,
subwavelength imaging, quantum optics and
renewable energy sources.
Already, the project has demonstrated – in
partnership with the Agency for Science,
Technology and Research (A*STAR) Data Storage
Institute in Singapore – that silicon nanoparticles
only a few hundred nanometres in size exhibit
strong magnetic resonances in the visible spectrum.
“Such nanoparticles can be building blocks for new
types of light-matter interaction at the nanoscale,”
Miroshnichenko adds. In the coming years, he plans
to explore a new path – the topological properties
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of light, which dictate many physical phenomena.
“Currently in condensed matter physics, much
effort is devoted to studying topological insulators,
electronic materials that have a bulk band gap like
an ordinary insulator but protected conducting
states on their edge or surface,” he explains. The
focus has traditionally been on electronic systems,
but Miroshnichenko will investigate a more
emerging aspect – topological orders. “My future
research activity will be investigating new states of
photons in the context of quantum simulation, and
developing integrated photonic devices that are
resistant to disorder,” he concludes.
A MULTITUDE OF NEW TECHNOLOGIES
Optical sensing
By combining both strong near-field
enhancement and steep spectral variation of
the Fano resonance profile, Miroshnichenko
demonstrated that resonant nanostructures
can optically measure extremely small
changes to the surrounding bulk refractive
index. This paves the way for compact 3D
optical sensors, which could even have single
molecule sensitivity; a highly sought after
feature in biomedical science.
Data storage
Techniques for high-density optical data
storage have ushered in the 4th generation
of data storage, but new super-resolution
structures can introduce near-field optics
into the disk layer stack itself. This could
generate capacities of hundreds of gigabytes
per disk, but typically requires metallic
components, leading to heating and energy
losses. However, using lossless, highrefractive index dielectric nanoparticles with
strong magnetic response could overcome
these problems.
Controlled data processing
There is growing demand to engineer
electromagnetic fields in nanoscale
structures, accompanying the need for
faster computers. Semiconductor giants
are currently investigating the use of
optical interconnects within computer
chips, the first generation of which are
already available. However, it is also
important to actively control information
processing. Miroshnichenko will use tuneable
light-matter interaction to develop new
nanophotonic devices with light-controlled
properties, lower power consumption and
low fabrication costs.
Next generation solar cells
Establishing the limit of nanophotonic lighttrapping is crucial for solar cell research.
It is thought that resonant response of
high-index dielectric subwavelength
nanoparticles can be employed to enhance
the performance of optoelectronic devices,
based on novel approaches to design thinfilm light-trapping nanostructures for solar
cells applications.