Dr Marian Florescu


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Biography

Biography

Marian Florescu joined the University of Surrey in 2011. He graduated from the University of Bucharest with a BSc in Physics and then obtained his PhD in Theoretical Quantum Optics at the University of Toronto. Prior to joining the Physics Department at Surrey he was a Research Scholar and Lecturer at Princeton University and a National Research Council Research Associate at NASA Jet Propulsion Laboratory. His current activities are focused on the physics and applications of non-crystallographic photonic band gap materials, thermal radiation control in photonic materials and quantum optics in structured photonic reservoirs.

Please see my homepage above for further details of my research.

Research interests

MICRO- AND NANO-PHOTONICS

  • Fundamentals and applications of non-crystallographic photonic structures
  • Thermal radiation in nano-structured photonic materials; thermal management and thermophotovoltaic energy conversion
  • Quantum nonlinear optics and all-optical information processing in micro-structured photonic materials
  • Physics of structural colours in biophotonic nanostructures

NANO-ELECTRONICS AND SPINTRONICS

  • Temperature insensitive semiconductor materials: electronic structure and loss mechanisms in dilute bismide and nitride alloys
  • Hyperuniform disordered 2D and 3D electronic systems: amorphous graphene and silicon models
  • Flux quantization in disordered superconducting networks

LINEAR OPTICAL QUANTUM COMPUTING IN PHOTONIC NANOSTRUCTURES

  • Single-photon sources and detectors
  • Cavity-mediated entanglement of photonic and electronic excitations

Research collaborations

  • Imperial College London
  • University of Southampton
  • San Francisco State University
  • Princeton University
  • New York University
  • Humboldt University
  • Etaphase Inc.

Teaching

  • Level M: PHYM061 Advanced Nanophotonics
  • Level HE3: PHY3042 Modern Computational Techniques
  • Level HE3: PHY3046 Nanophotonics and its Applications
  • Level HE2: PHY2072 Light Lab
  • Level HE2: PHY2065 Electromagnetic Waves

Departmental duties

  • Director of Research Physics Department
  • Head Theory and Computation Group
  • Level 1 Coordinator
  • Member of the Board of Studies Sub-Committee
  • Member of Staff Student Liaison Committee
  • Departmental Representative Additional Learning Support

My publications

Publications

Gkantzounis G, Amoah T, Florescu M (2017) Hyperuniform disordered phononic structures, Physical Review B 95 (9) 094120 American Physical Society
We demonstrate the existence of large phononic band gaps in designed hyperuniform (isotropic) disordered two-dimensional (2D) phononic structures of Pb cylinders in epoxy matrix. The phononic band gaps in hyperuniform disordered phononic structures are comparable to band gaps of similar periodic structures, for both out-of-plane and in-plane polarizations. A large number of localized modes is identi ed near the band edges, as well as, di usive transmission throughout the rest of the frequency spectrum. Very high-Q cavity modes for both out-of-plane and in-plane polarizations are formed by selectively removing a single cylinder out of the structure. E cient waveguiding with almost 100% transmission trough waveguide structures with arbitrary bends is also presented. We expand our results to thin three-dimensional layers of such structures and demonstrate e ective band gaps related to the respective 2D band gaps. Moreover, the drop in the Q factor for the three-dimensional structures is not more than three orders of magnitude compared to the 2D ones.
Florescu M, Lee H, Stimpson AJ, Dowling J (2005) Thermal emission and absorption of radiation in finite inverted-opal photonic crystals, PHYSICAL REVIEW A 72 (3) ARTN 033821 AMERICAN PHYSICAL SOC
Florescu M, Amoah T (2015) High-Q optical cavities in hyperuniform disordered materials, Physical Review B: Condensed Matter and Materials Physics 91 pp. 020201-1-020201-5 American Physical Society
MilosÇevic M, Florescu M, Man W, Steinhardt P, Torquato S, Chaikin P, Amoah T, Nahal G, Mullen R (2014) Silicon waveguides and filters in hyperuniform disordered photonic solids for the near-infrared, Optical Fiber Communication Conference, OFC 2014
We report preliminary results for silicon waveguides and devices in hyperuniform disordered photonic solids. Temperature sensitivity of resonant defects is more than 500 times lower than that of the standard silicon microring resonators. © 2013 Optical Society of America.
Florescu M, Torquato S, Steinhardt PJ (2009) Complete band gaps in two-dimensional photonic quasicrystals, PHYSICAL REVIEW B 80 (15) ARTN 155112 AMER PHYSICAL SOC
Florescu M, Scheel S, Haeffner H, Lee H, Strekalov DV, Knight PL, Dowling JP (2002) Single photons on demand from 3D photonic band-gap structures, Europhysics Letterrs 69
We describe a practical implementation of a (semi-deterministic) photon gun
based on stimulated Raman adiabatic passage pumping and the strong enhancement
of the photonic density of states in a photonic band-gap material. We show that
this device allows {\em deterministic} and {\em unidirectional} production of
single photons with a high repetition rate of the order of 100kHz. We also
discuss specific 3D photonic microstructure architectures in which our model
can be realized and the feasibility of implementing such a device using
${Er}^{3+}$ ions that produce single photons at the telecommunication
wavelength of $1.55 \mu$m.
Geev N, Man W, Florescu M, Steinhardt P, Torquato S, Chaikin P, Mullen RA New designer dielectric metamaterial with isotropic photonic band gap, (480)
Florescu M, John S (2002) All-optical transistor action in photonic band gap materials, APPLICATIONS OF PHOTONIC TECHNOLOGY 5 4833 pp. 513-524 SPIE-INT SOC OPTICAL ENGINEERING
Florescu M, Busch K (2009) Properties of thermal radiation in photonic crystals, JOURNAL OF OPTICS A-PURE AND APPLIED OPTICS 11 (11) IOP PUBLISHING LTD
Schuler CJ, Wolff C, Busch K, Florescu M (2010) Thermal emission from finite photonic crystals, ACTIVE PHOTONIC MATERIALS III 7756 SPIE-INT SOC OPTICAL ENGINEERING
John S, Florescu M (2001) Photonic bandgap materials: towards an all-optical micro-transistor, JOURNAL OF OPTICS A-PURE AND APPLIED OPTICS 3 (6) pp. S103-S120 IOP PUBLISHING LTD
Florescu M, John S (2004) Resonance fluorescence in photonic band gap waveguide architectures: Engineering the vacuum for all-optical switching, Physical Review A - Atomic, Molecular, and Optical Physics 69 (5 B) pp. 053810-1
Bushell Z, Florescu M, Sweeney SJ High-Q photonic crystal cavities in all-semiconductor heterostructures, University of Surrey
Florescu M, Dickman S, Ciorga M, Sachrajda A, Hawrylak P (2004) Spin-orbit interaction and spin relaxation in a lateral quantum dot, PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES 22 (1-3) pp. 414-417 ELSEVIER SCIENCE BV
Scheel S, Florescu M, Haffner H, Lee H, Strekalov DV, Knight PL, Dowling JP (2007) Single photons on demand from tunable 3D photonic band-gap structures, JOURNAL OF MODERN OPTICS 54 (2-3) pp. 409-416 TAYLOR & FRANCIS LTD
Milosevic M, Florescu M, Man W, Nahal G, Tsitrin S, Amoah T, Steinhardt PJ, Torquato S, Mullen RA (2014) Hyperuniform disordered photonic band gap silicon devices for optical interconnects, Optical Interconnects Conference, 2014 IEEE
Florescu M, Steinhardt PJ, Torquato S (2013) Erratum: Optical cavities and waveguides in hyperuniform disordered photonic solids (Physical Review B (2013) 87 (165116) DOI:10.1103/PhysRevB.87.165116), Physical Review B - Condensed Matter and Materials Physics 87 (15)
Amoah T, Florescu M (2015) Flexible cavity and waveguide light confinement in hyperuniform photonic slabs, Optical Sensors, Sensors 2015
We introduce novel planar hyperuniform-disordered (HUD) architectures as potential general-purpose platform for optical microcircuits. Efficient confinement of TE-polarized radiation and high-Q optical-cavities and low-loss waveguides is demonstrated using finite difference-time-domain and band-structure simulations. © 2015 Optical Society of America.
Maspero R, Sweeney SJ, Florescu M (2013) Modelling the Auger Recombination rates of GaAs(1-x)Bi x alloys, 13th International Conference on Numerical Simulation of Optoelectronic Devices, NUSOD 2013 pp. 81-82
We calculate the Conduction, Heavy Hole (HH) - Split-off Hole (SO), HH (CHSH) Auger Recombination rates for GaAs(1-x)Bix alloys, which are candidates for highly efficient telecommunication devices. A ten-band, tight-binding method, including spin-orbit coupling, was performed on a 9×9×9 strained supercell in order to generate an accurate band structure to perform the calculation on. This band structure was then unfolded to give a true E-k relation. As predicted by experiment, there should be a decrease in the Auger recombination rate as the concentration of Bismuth increases ending in a suppression at greater than
Florescu M, Torquato S, Steinhardt PJ (2009) New classes of non-crystalline photonic band gap materials, Proccedings of The European Conference on Lasers and Electro-Optics and the XIth European Quantum Electronics Conference
Spedalieri FM, Lee H, Florescu M, Kapale KT, Yurtsever U, Dowling JP (2004) Exploiting the quantum Zeno effect to beat photon loss in linear optical
quantum information processors,
Optics Communications
We devise a new technique to enhance transmission of quantum information
through linear optical quantum information processors. The idea is based on
applying the Quantum Zeno effect to the process of photon absorption. By
frequently monitoring the presence of the photon through a QND (quantum
non-demolition) measurement the absorption is suppressed. Quantum information
is encoded in the polarization degrees of freedom and is therefore not affected
by the measurement. Some implementations of the QND measurement are proposed.
Wache R, Florescu M, Sweeney SJ, Clowes SK (2015) Selectively reflective transparent sheets, ACTIVE PHOTONIC MATERIALS VII 9546 SPIE-INT SOC OPTICAL ENGINEERING
Florescu M, Busch K, Dowling JP (2007) Thermal radiation in photonic crystals, PHYSICAL REVIEW B 75 (20) ARTN 201101 AMERICAN PHYSICAL SOC
Florescu M, Hawrylak P (2006) Spin relaxation in lateral quantum dots: Effects of spin-orbit interaction, PHYSICAL REVIEW B 73 (4) ARTN 045304 AMER PHYSICAL SOC
Florescu M, Torquato S, Steinhardt PJ (2009) Designer disordered materials with large, complete photonic band gaps., Proc Natl Acad Sci U S A 106 (49) pp. 20658-20663
We present designs of 2D, isotropic, disordered, photonic materials of arbitrary size with complete band gaps blocking all directions and polarizations. The designs with the largest band gaps are obtained by a constrained optimization method that starts from a hyperuniform disordered point pattern, an array of points whose number variance within a spherical sampling window grows more slowly than the volume. We argue that hyperuniformity, combined with uniform local topology and short-range geometric order, can explain how complete photonic band gaps are possible without long-range translational order. We note the ramifications for electronic and phononic band gaps in disordered materials.
Florescu M, Torquato S, Steinhardt P (2012) Photonic Band Gaps and Unusual Photon Transport in Hyperuniform Disordered Structures, Frontiers in Optics 2012/Laser Science XXVIII, OSA Technical Digest (online) Optical Society of America
We demonstrate that hyperuniform disordered structures support electromagnetic states
with very different transport properties, ranging from Bloch-like modes to diffusive states with characteristic time scales almost two-orders of magnitude larger.
Amoah T, Florescu M (2015) Flexible cavity andwaveguide light confinement in hyperuniform photonic slabs, Integrated Photonics Research, Silicon and Nanophotonics, IPRSN 2015
We introduce novel planar hyperuniform-disordered (HUD) architectures as potential general-purpose platform for optical microcircuits. Efficient confinement of TE-polarized radiation and high-Q optical-cavities and low-loss waveguides is demonstrated using finite difference-time-domain and band-structure simulations. © 2015 Optical Society of America.
Florescu M, Steinhardt PJ, Torquato S (2013) Optical cavities and waveguides in hyperuniform disordered photonic solids, Physical Review B - Condensed Matter and Materials Physics 87 (16)
Amoah T, Florescu M (2015) Flexible cavity and waveguide light confinement in hyperuniform photonic slabs, Photonic Networks and Devices, Networks 2015
We introduce novel planar hyperuniform-disordered (HUD) architectures as potential general-purpose platform for optical microcircuits. Efficient confinement of TE-polarized radiation and high-Q optical-cavities and low-loss waveguides is demonstrated using finite difference-time-domain and band-structure simulations. © 2015 Optical Society of America.
Amoah T, Florescu M (2015) Hyperuniform photonic slabs for high-Q cavities and low-loss waveguides, ACTIVE PHOTONIC MATERIALS VII 9546
Florescu M, Lee H, Dowling JP (2005) On the emission and absorption of thermal radiation in photonic crystals, Optics InfoBase Conference Papers
We investigate the general features of thermal emission and absorption of radiation in photonic crystals. The light-matter interaction is strongly affected by the presence of the three-dimensional photonic crystal and the alteration of the photonic density of states can be used to suppress or enhance the thermal emissivity and absorptivity of the dielectric structure. Our analysis shows that the thermal response of the system depends on both the elementary absorbers/emitters and the photonic reservoir characteristics. In particular, we demonstrate that, depending on the system configuration, the thermal emission may exceed the free-space radiative energy density given by Planck's law. This modification of the Planck's law is achieved without altering the optical properties of the absorber/emitter medium, which remain consistent with the usual definition of a frequency and angle dependent grey-body. We also evaluate the rate of spontaneous emission, stimulated emission and absorption for thermally driven two-level atomic systems in a photonic crystal, and introduce effective A and B coefficients for the case of a photonic crystal. © 2005 OSA/FIO.
Man WN, Florescu M, Matsuyama K, Yadak P, Torquato S, Steinhardt P, Chaikin P (2010) Experimental observation of photonic bandgaps in hyperuniform disordered material, 2010 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO) AND QUANTUM ELECTRONICS AND LASER SCIENCE CONFERENCE (QELS) IEEE
Amoah T, Florescu M (2015) Flexible cavity and waveguide light confinement in hyperuniform photonic slabs, Novel Optical Materials and Applications, NOMA 2015
We introduce novel planar hyperuniform-disordered (HUD) architectures as potential general-purpose platform for optical microcircuits. Efficient confinement of TE-polarized radiation and high-Q optical-cavities and low-loss waveguides is demonstrated using finite difference-time-domain and band-structure simulations. © 2015 Optical Society of America.
Florescu M, Scheel S, Lee H, Knight PL, Bowling JP (2006) Three-dimensional photonic band-gap structures for single-photon on demand sources, ICTON 2006: 8th International Conference on Transparent Optical Networks, Vol 2, Proceedings pp. 40-43 IEEE
Miloaevi? MM, Florescu M, Man W, Nahal G, Tsitrin S, Amoah T, Steinhardt PJ, Torquato S, Chaikin PM, Mullen RA (2014) Hyperuniform disordered photonic band gap devices for silicon photonics, IEEE International Conference on Group IV Photonics GFP pp. 33-34
© 2014 IEEE.We report experimental and simulation results for silicon waveguides and resonant cavities in hyperuniform disordered photonic solids. Our results demonstrate the ability of disordered photonic bandgap materials to serve as a platform for silicon photonics.
Miloaevi? M, Florescu M, Amoah T, Man W, Nahal G, Steinhardt P, Torquato S, Chaikin P, Mullen R (2014) Silicon waveguides and filters in hyperuniform disordered photonic solids for the near-infrared, Optics InfoBase Conference Papers
We report preliminary results for silicon waveguides and devices in hyperuniform disordered photonic solids. Temperature sensitivity of resonant defects is more than 500 times lower than that of the standard silicon microring resonators. © 2013 Optical Society of America.
Man W, Florescu M, Matsuyama M, Yadak P, Nahal G, Hamshezad S, Williamson E, Steinhardt P, Torquato S, Chaikin P (2013) Photonic band gap in isotropic hyperuniform disordered solids with low dielectric contrast, Optics Express 21 (17) pp. 19972-19981
Tsitrin S, Nahal G, Man W, Florescu M, Miloaevi? MM, Mullen RA, Steinhardt P, Torquato S, Chaikin P (2014) Fabrication and optimization for waveguides in sub-micron scale hyperuniform disordered photonic bandgap materials, Optics InfoBase Conference Papers
We report experimental and simulation results for low-loss wave-guiding in Si-based hyperuniform disordered photonic bandgap materials at infrared wavelengths. These results pave the way for deploying disordered photonic solids in integrated photonic circuits. © 2014 Optical Society of America.
Florescu M, Man W, Mullen RA, Milosevic M, Amoah T, Chaikin PM, Torquato S, Steinhardt P (2014) Isotropic band gaps, optical cavities, and freeform waveguides in hyperuniform disordered photonic solids, Proc. SPIE 9162, Active Photonic Materials VI, 91620G (September 12, 2014)
Amoah T, Florescu M (2015) Light confinement in hyperuniform photonic slabs: High-Q cavities and low-loss waveguides, CLEO: Science and Innovations, CLEO-SI 2015
Using finite-difference-time-domain and band-structure simulations, we demonstrate efficient confinement of TE-polarized radiation and high-Q optical-cavities and low-loss waveguides in planar hyperuniform-disordered (HUD) architectures based on a design strategy that has potential to be a general purpose platform for optical microcircuits. © OSA 2015.
Florescu M, Tsitrin S, Williamson E, Amoah T, Nahal G, Chan L, Man W (2015) Unfolding the band structure of non-crystalline photonic band gap materials, Scientific Reports 5 13301 pp. 1-8 Nature Publishing Group
Florescu M, John S (2001) Single-atom switching in photonic crystals, Physical Review A. Atomic, Molecular, and Optical Physics 64 (3) pp. 033801/1-033801/21 American Physical Society
Florescu M, Lee H, Puscasu I, Pralle M, Florescu L, Ting DZ, Dowling JP (2007) Improving solar cell efficiency using photonic band-gap materials, SOLAR ENERGY MATERIALS AND SOLAR CELLS 91 (17) pp. 1599-1610 ELSEVIER SCIENCE BV
Amoah T, Florescu M (2015) Flexible cavity and waveguide light confinement in hyperuniform photonic slabs, Signal Processing in Photonic Communications, SPPCom 2015
We introduce novel planar hyperuniform-disordered (HUD) architectures as potential general-purpose platform for optical microcircuits. Efficient confinement of TE-polarized radiation and high-Q optical-cavities and low-loss waveguides is demonstrated using finite difference-time-domain and band-structure simulations. © 2015 Optical Society of America.
Florescu M, Torquato S, Steinhardt PJ (2009) New classes of non-crystalline photonic band gap materials, Optics InfoBase Conference Papers
Florescu M, Sellers S Local Self-Uniformity in Photonic Networks, University of Surrey
Tsitrin S, He Y, Hewatt S, Leung B, Man W, Florescu M, Steinhardt PJ, Torquato S, Chaikin P (2012) Cavity Modes Study in Hyperuniform Disordered Photonic Bandgap Materials, Frontiers in Optics 2012/Laser Science XXVIII, OSA Technical Digest (online) Optical Society of America
We introduce novel architecture for cavity design in an isotropic disordered
photonic band gap material. We demonstrate that point-like defects can support localized
modes with different symmetries and multiple resonant frequencies, useful for various
applications.
Schuler CJ, Wolff C, Busch K, Florescu M (2009) Thermal emission from finite photonic crystals, APPLIED PHYSICS LETTERS 95 (24) ARTN 241103 AMER INST PHYSICS
Man W, Florescu M, Williamson EP, He Y, Hashemizad SR, Leung BY, Liner DR, Torquato S, Chaikin P, Steinhardt PJ (2013) Isotropic band gaps and freeform waveguides observed in hyperuniform disordered photonic solids, Proceedings of the National Academy of Sciences of USA 120 (40) pp. 15886-15891
Man W, Florescu M, Matsuyama K, Yadak P, Torquato S, Steinhardt P, Chaikin P (2010) Experimental observation of photonic bandgaps in hyperuniform disordered material, Optics InfoBase Conference Papers
We report the first experimental demonstration of photonic bandgaps (PBGs) in 2D hyperuniform disordered materials and show that is possible to obtain isotropic, disordered, photonic materials of arbitrary size with complete PBGs. © 2010 Optical Society of America.
Miloaevi? M, Florescu M, Man W, Steinhardt P, Torquato S, Chaikin P, Amoah T, Nahal G, Mullen R (2014) Silicon waveguides and filters in hyperuniform disordered photonic solids for the near-infrared, Conference on Optical Fiber Communication, Technical Digest Series
We report preliminary results for silicon waveguides and devices in hyperuniform disordered photonic solids. Temperature sensitivity of resonant defects is more than 500 times lower than that of the standard silicon microring resonators. © 2014 OSA.
Man W, He Y, Leung R, Tsitrin S, Florescu M, Steinhardt PJ, Torquato S, Chaikin P (2012) Freeform wave-guiding and tunable frequency splitting in isotropic disordered photonic band gap materials,
Florescu M, Steinhardt PJ, Torquato S Narrow-band frequency filters and splitters, photonic sensors, and cavities having pre-selected cavity modes,
Waveguides and electromagnetic cavities fabricated in hypemniform disordered materials with complete photonic bandgaps are provided. Devices comprising electromagnetic cavities fabricated in hypemniform disordered materials with complete photonic bandgaps are provided. Devices comprising waveguides fabricated in hypemniform disordered materials with complete photonic bandgaps are provided. The devices include electromagnetic splitters, filters, and sensors.
Nahal G, Florescu M, Mullen RA, Steinhardt P, Torquato S, Chaikin P, Man W (2013) Freeform wave-guiding at infrared regime in two dimensional disordered photonic bandgap materials, Optics InfoBase Conference Papers
We report the first experimental demonstration of guiding, bending and power-splitting of light in 2D disordered photonic bandgap materials at infrared wavelengths, along curved paths, around sharp bends of arbitrary angles, and through Y-shape junctions. © 2013 Optical Society of America.
Castro-Lopez M, Gaio M, Sellers Steven, Gkantzounis Georgios, Florescu Marian, Sapienza R (2017) Reciprocal space engineering with hyperuniform gold
disordered surfaces,
APL Photonics 2 (6) 061302 AIP Publishing LLC
Hyperuniform geometries feature correlated disordered topologies which follow
from a tailored k-space design. Here, we study gold plasmonic hyperuniform
disordered surfaces and, by momentum spectroscopy, we report evidence of kspace
engineering on both light scattering and light emission. Even if the structures
lack a well-defined periodicity, emission and scattering are directional in
ring-shaped patterns. The opening of these rotational-symmetric patterns scales
with the hyperuniform correlation length parameter as predicted via the spectral
function method.
Bushell Z, Florescu M, Sweeney S (2017) High-Q photonic crystal cavities in all-semiconductor photonic crystal heterostructures, Physical Review B 95 (23) 235303 American Physical Society
Photonic crystal cavities enable the realization of high Q-factor and low mode-volume resonators, with typical architectures consisting of a thin suspended periodically patterned layer to maximize confinement of light by strong index guiding. We investigate a heterostructure-based approach comprising a high refractive index core and lower refractive index cladding layers. While confinement typically decreases with decreasing index contrast between the core and cladding layers, we show that, counterintuitively, due to the confinement provided by the photonic band structure in the cladding layers, it becomes possible to achieve Q factors
>
10
4
with only a small refractive index contrast. This opens up opportunities for implementing high-Q factor cavities in conventional semiconductor heterostructures, with direct applications to the design of electrically pumped nanocavity lasers using conventional fabrication approaches.
Utgenannt A, Maspero R, Fortini A, Turner R, Florescu M, Jeynes C, Kanaras A, Muskens O, Sear RPL, Keddie JL (2016) Fast Assembly of Gold Nanoparticles in Large-Area 2-D Nanogrids Using a One-Step, Near-Infrared Radiation-Assisted Evaporation Process, ACS Nano 10 (2) pp. 2232-2242 American Chemical Society
When fabricating photonic crystals from suspensions in volatile liquids using the horizontal deposition method, the conventional approach is to evaporate slowly to increase the time for particles to settle in an ordered, periodic close-packed structure. Here, we show that the greatest ordering of 10 nm aqueous gold nanoparticles (AuNPs) in a template of larger spherical polymer particles (mean diameter of 338 nm) is achieved with very fast water evaporation rates obtained with near-infrared radiative heating. Fabrication of arrays over areas of a few cm2 takes only seven minutes. The assembly process requires that the evaporation rate is fast relative to the particles? Brownian diffusion. Then a two-dimensional colloidal crystal forms at the falling surface, which acts as a sieve through which the AuNPs pass, according to our Langevin dynamics computer simulations. With sufficiently fast evaporation rates, we create a hybrid structure consisting of a two-dimensional AuNP nanoarray (or ?nanogrid?) on top of a three-dimensional polymer opal. The process is simple, fast and one-step. The interplay between the optical response of the plasmonic Au nanoarray and the microstructuring of the photonic opal results in unusual optical spectra with two extinction peaks, which are analyzed via finite-difference time-domain method simulations. Comparison between experimental and modelling results reveals a strong interplay of plasmonic modes and collective photonic effects, including the formation of a high-order stop band and slow-light enhanced plasmonic absorption. The structures, and hence their optical signatures, are tuned by adjusting the evaporation rate via the infrared power density.
Florescu M, Torquato S, Steinhardt P (2010) Effects of random link removal on the photonic band gaps of honeycomb networks, APPLIED PHYSICS LETTERS 97 (20) 201103 AMER INST PHYSICS
Maspero R, Sweeney S, Florescu M (2016) Unfolding the band structure of GaAsBi, Journal of Physics: Condensed Matter 29 (7) 075001 Institute of Physics
Typical supercell approaches used to investigate the electronic properties of GaAs(1?x)Bi(x) produce highly accurate, but folded, band structures. Using a highly optimized algorithm, we unfold the band structure to an approximate $E\left(\mathbf{k}\right)$ relation associated with an effective Brillouin zone. The dispersion relations we generate correlate strongly with experimental results, confirming that a regime of band gap energy greater than the spin?orbit-splitting energy is reached at around 10% bismuth fraction. We also demonstrate the effectiveness of the unfolding algorithm throughout the Brillouin zone (BZ), which is key to enabling transition rate calculations, such as Auger recombination rates. Finally, we show the effect of disorder on the effective masses and identify approximate values for the effective mass of the conduction band and valence bands for bismuth concentrations from 0?12%.
Sellers S, Man W, Sahba S, Florescu M (2017) Local self-uniformity in photonic networks, Nature Communications 8 14439 Nature Publishing Group
The interaction of a material with light is intimately related to its wavelength-scale structure. Simple connections between structure and optical response empower us with essential intuition to engineer complex optical functionalities. Here we develop local self-uniformity as a novel measure of a random network?s internal structural similarity, ranking networks on a continuous scale from crystalline, through glassy intermediate states, to chaotic configurations. We demonstrate that complete photonic band gap structures possess substantial local selfuniformity and validate local self-uniformity?s importance in gap formation through design of novel amorphous gyroid structures. Amorphous gyroid samples are fabricated via 3D ceramic printing and the band gaps experimentally verified. We explore also the wing-scale structuring in the butterfly Pseudolycaena marsyas and show that it possesses substantial amorphous gyroid character, demonstrating the subtle order achieved by evolutionary optimisation and the possibility of an amorphous gyroid?s self-assembly.
Florescu M, Scheel S, Lee H, Knight P, Dowling J (2006) Nonlinear tuning of 3D photonic band-gap structures for single-photon on demand sources, PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES 32 (1-2) pp. 484-487 Elsevier
Florescu M, Scheel S, Knight P, Lee H, Dowling J (2006) Nonlinear tuning of 3D photonic band-gap structures for single-photon on demand sources, Physica E: Low-Dimensional Systems and Nanostructures 32 (1-2 SP) pp. 484-487 Elsevier
We describe a practical implementation of a semi-deterministic photon gun based on the stimulated Raman adiabatic passage pumping and the nonlinear tuning of the photonic density of states in a photonic band-gap material. We show that this device allows deterministic and unidirectional production of single photons with a high repetition rate of the order of 100 kHz. We also discuss specific 3D photonic microstructure architectures in which our model can be realized and the feasibility of implementing such a device using Er ions that produce single photons at the telecommunication wavelength of 1.55 ¼ m. © 2006 Elsevier B.V. All rights reserved.
Man W, Florescu M, Hashemizad S, He Y, Leung R, Williamson E, Chaikin P (2012) Experimental demonstration of guiding, bending, and filtering of electromagnetic wave in disordered photonic band gap materials, Conference on Lasers and Electro-Optics 2012, OSA Technical Digest
We report the first experimental demonstration of guiding, bending, filtering, and splitting of EM wave in 2D disordered PBG materials, along arbitrarily curved paths, around sharp bends of arbitrary angles, and through Y shape junctions. © 2012 OSA.
Florescu Marian (2018) Freeform Phononic Waveguides, University of Surrey
Gkantzounis Georgios, Florescu Marian (2017) Freeform Phononic Waveguides, Crystals 7 (12)
We employ a recently introduced class of artificial structurally-disordered phononic structures that exhibit large and robust elastic frequency band gaps for efficient phonon guiding. Phononic crystals are periodic structures that prohibit the propagation of elastic waves through destructive interference and exhibit large band gaps and ballistic propagation of elastic waves in the permitted frequency ranges. In contrast, random-structured materials do not exhibit band gaps and favour localization or diffusive propagation. Here, we use structures with correlated disorder constructed from the so-called stealthy hyperuniform disordered point patterns, which can smoothly vary from completely random to periodic (full order) by adjusting a single parameter. Such amorphous-like structures exhibit large band gaps (comparable to the periodic ones), both ballistic-like and diffusive propagation of elastic waves, and a large number of localized modes near the band edges. The presence of large elastic band gaps allows the creation of waveguides in hyperuniform materials, and we analyse various waveguide architectures displaying nearly 100% transmission in the GHz regime. Such phononic-circuit architectures are expected to have a direct impact on integrated micro-electro-mechanical filters and modulators for wireless communications and acousto-optical sensing applications.

Additional publications