Professor Marian Florescu

Professor of Physics
+44 (0)1483 686813
26 ATI 02

Academic and research departments

Department of Physics, Advanced Technology Institute.



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


  • 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


  • 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


  • 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.


  • Level M: PHYM061 Advanced Nanophotonics
  • Level HE3: PHY3046 Nanophotonics and its Applications
  • Level HE2: PHY2064 Electromagnetism, Scalar and Vector Fields
  • Level HE2: PHY2065 Electromagnetic Waves

Departmental duties

  • Director of Research and Innovation Physics Department
  • Head Theory and Computation Group
  • Chair HPC Stakeholder Group


Postgraduate research supervision


Nicoletta Granchi, Richard Spalding, Kris Stokkereit, Matteo Lodde, Maurangelo Petruzzella, Frank V. Otten, Andrea Fiore, Marian Florescu, Francesca Intonti (2023)High spatial resolution imaging of light localization in hyperuniform disordered patterns of circular air pores in a dielectric slab, In: Frontiers in Photonics41199411 Frontiers Media

Hyperuniform disordered photonic structures are a peculiar category of disordered photonic heterostructures located between random structures and ordered photonic crystals. These materials, thanks to the presence of a photonic bandgap, exhibit the advantages of random and ordered structures since they have been shown to support in a small spatial footprint a high density of Anderson-localized modes, which naturally occur at the bandgap edges with peculiar features like relatively high Q/V ratios. Different localization behaviors have been recently reported in hyperuniform disordered luminescent materials, with a well-established and widely studied design, based on disordered networks. Here, we explore an alternative design, based on circular holes of different sizes hyperuniformely distributed, that we investigate theoretically and experimentally by means of scanning near-field optical microscopy. We report that the spectral features of hyperuniform disordered networks can also be extended to a different design, which, in turn, displays pseudo-photonic bandgaps and light localization. The ability of generating different kinds of hyperuniform disordered photonic systems that share the same theoretical and experimental optical features can largely extend practical potentialities and integration in many optoelectronic applications.

ZL Bushell, Marian Florescu, Stephen Sweeney (2017)High-Q photonic crystal cavities in all-semiconductor photonic crystal heterostructures, In: Physical Review B95(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.

Adam Burgess, Marian Florescu (2023)Quantum memory effects in atomic ensembles coupled to photonic cavities Quantum memory effects in atomic ensembles coupled to photonic cavities, In: AVS Quantum Science5(1)11402pp. 011402-1-011402-11 American Institute of Physics

This article explores the dynamics of many-body atomic systems symmetrically coupled to Lorentzian photonic cavity systems. Our study reveals interesting dynamical characteristics, including non-zero steady states, super-radiant decay, enhanced energy transfer, and the ability to modulate oscillations in the atomic system by tuning environmental degrees of freedom. We also analyze a configuration consisting of a three-atom chain embedded in a photonic cavity. Similarly, we find a strong enhancement of the energy transfer rate between the two ends of the chain and identified specific initial conditions that lead to significantly reduced dissipation between the two atoms at the end of the chain. Another configuration of interest consists of two symmetrical detuned reservoirs with respect to the atomic system. In the single atom case, we show that it is possible to enhance the decay rate of the system by modulating its reservoir detuning. In contrast, in the many-atom case, this results in dynamics akin to the on-resonant cavity. Finally, we examine the validity of the rotating wave approximation through a direct comparison against the numerically exact hierarchical equations of motion. We find good agreement in the weak coupling regime, while in the intermediate coupling regime, we identify qualitative similarities, but the rotating wave approximation becomes less reliable. In the moderate coupling regime, we find deviations of the steady states due to the formation of mixed photon-atom states.

M Florescu, T Amoah (2015)High-Q optical cavities in hyperuniform disordered materials, In: Physical Review B: Condensed Matter and Materials Physics91pp. 020201-1 American Physical Society

We introduce designs for high-Q photonic cavities in slab architectures in hyperuniform disordered solids displaying isotropic band gaps. Despite their disordered character, hyperuniform disordered structures have the ability to tightly confine the transverse electric-polarized radiation in slab configurations that are readily fabricable. The architectures are based on carefully designed local modifications of otherwise unperturbed hyperuniform dielectric structures. We identify a wide range of confined cavity modes, which can be classified according to their approximate symmetry (monopole, dipole, quadrupole, etc.) of the confined electromagnetic wave pattern. We demonstrate that quality factors Q>109 can be achieved for purely two-dimensional structures, and that for three-dimensional finite-height photonic slabs, quality factors Q>20000 can be maintained.

M Milosevic, M Florescu, W Man, G Nahal, S Tsitrin, T Amoah, PJ Steinhardt, S Torquato, RA Mullen (2014)Hyperuniform disordered photonic band gap silicon devices for optical interconnects, In: Optical Interconnects Conference, 2014 IEEE
W Man, M Florescu, EP Williamson, Y He, SR Hashemizad, BY Leung, DR Liner, S Torquato, P Chaikin, PJ Steinhardt (2013)Isotropic band gaps and freeform waveguides observed in hyperuniform disordered photonic solids, In: Proceedings of the National Academy of Sciences of USA120(40)pp. 15886-15891
M Florescu, S Torquato, PJ Steinhardt (2010)Effects of random link removal on the photonic band gaps of honeycomb networks, In: APPLIED PHYSICS LETTERS97(20)ARTN 2pp. ?-? AMER INST PHYSICS
M Florescu, S Scheel, HH Haffner, H Lee, D Strekalov, PL Knight, JP Dowling (2005)Single photons on demand from 3D photonic band-gap structures, In: EUROPHYSICS LETTERS69(6)pp. 945-951 EDP SCIENCES S A
M Florescu, P Hawrylak (2006)Spin relaxation in lateral quantum dots: Effects of spin-orbit interaction, In: PHYSICAL REVIEW B73(4)ARTN 0pp. ?-? AMER PHYSICAL SOC
M Florescu, S John (2004)Resonance fluorescence in photonic band gap waveguide architectures: Engineering the vacuum for all-optical switching, In: Physical Review A - Atomic, Molecular, and Optical Physics69(5 B)pp. 053810-1
Ilham Maimouni, Maryam Morvaridi, Maria Russo, Gianluc Lui, Konstantin Morozov, Janine Cossy, Marian Florescu, Matthieu Labousse, Patrick Tabeling (2020)Micrometric Monodisperse Solid Foams as Complete Photonic Bandgap Materials, In: ACS Applied Materials & Interfaces12(28)pp. 32061-32068 American Chemical Society

Solid foams with micrometric pores are used in different fields (filtering, 3D cell culture, etc.), but today, controlling their foam geometry at the pore level, their internal structure, and the monodispersity, along with their mechanical properties, is still a challenge. Existing attempts to create such foams suffer either from slow speed or size limitations (above 80 μm). In this work, by using a temperature-regulated microfluidic process, 3D solid foams with highly monodisperse open pores (PDI lower than 5%), with sizes ranging from 5 to 400 μm and stiffnesses spanning 2 orders of magnitude, are created for the first time. These features open the way for exciting applications, in cell culture, filtering, optics, etc. Here, the focus is set on photonics. Numerically, these foams are shown to open a 3D complete photonic bandgap, with a critical index of 2.80, thus compatible with the use of rutile TiO2. In the field of photonics, such structures represent the first physically realizable self-assembled FCC (face-centered cubic) structure that possesses this functionality.

S Tsitrin, G Nahal, W Man, M Florescu, MM Milošević, RA Mullen, P Steinhardt, S Torquato, P Chaikin (2014)Fabrication and optimization for waveguides in sub-micron scale hyperuniform disordered photonic bandgap materials, In: 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.

CJ Schuler, C Wolff, K Busch, M Florescu (2009)Thermal emission from finite photonic crystals, In: APPLIED PHYSICS LETTERS95(24)ARTN 2pp. ?-? AMER INST PHYSICS
M Florescu, H Lee, AJ Stimpson, J Dowling (2005)Thermal emission and absorption of radiation in finite inverted-opal photonic crystals, In: PHYSICAL REVIEW A72(3)ARTN 0pp. ?-? AMERICAN PHYSICAL SOC
S Scheel, M Florescu, H Häffner, H Lee, DV Strekalov, PL Knight, JP Dowling (2007)Single photons on demand from tunable 3D photonic band-gap structures, In: Journal of Modern Optics54(3-4)pp. 409-416

In this article we propose to build a (semi-)deterministic photon gun by modifying the spontaneous decay in a photonic band-gap material. We show that such a device allows for deterministic and unidirectional single-photon emission with a repetition rate of the order of 100 kHz. We describe a specific realization of the 1D band-gap model by means of a 3D photonic-crystal heterostructure and the feasability of implementing such a device using Er3+ ions that produce single photons at the telecommunication wavelength of 1.55,m, important for many applications.

Milan M. Milošević, Weining Man, Geev Nahal, Paul J. Steinhardt, Salvatore Torquato, Paul M. Chaikin, Timoth Amoah, Bowen Yu, Ruth Ann Mullen, Marian Florescu (2019)Hyperuniform disordered waveguides and devices for near infrared silicon photonics, In: Scientific Reports9(1)20338 Nature Publishing Group

We introduce a hyperuniform-disordered platform for the realization of near-infrared photonic devices on a silicon-on-insulator platform, demonstrating the functionality of these structures in a fexible silicon photonics integrated circuit platform unconstrained by crystalline symmetries. The designs proposed advantageously leverage the large, complete, and isotropic photonic band gaps provided by hyperuniform disordered structures. An integrated design for a compact, sub-volt, sub-fJ/ bit, hyperuniform-clad, electrically controlled resonant optical modulator suitable for fabrication in the silicon photonics ecosystem is presented along with simulation results. We also report results for passive device elements, including waveguides and resonators, which are seamlessly integrated with conventional silicon-on-insulator strip waveguides and vertical couplers. We show that the hyperuniform-disordered platform enables improved compactness, enhanced energy efciency, and better temperature stability compared to the silicon photonics devices based on rib and strip waveguides.

M Florescu, S Tsitrin, E Williamson, T Amoah, G Nahal, L Chan, W Man (2015)Unfolding the band structure of non-crystalline photonic band gap materials, In: Scientific Reports513301pp. 1-8 Nature Publishing Group
M Florescu, PJ Steinhardt, S Torquato (2013)Optical cavities and waveguides in hyperuniform disordered photonic solids, In: PHYSICAL REVIEW B87(16)ARTN 1pp. ?-? AMER PHYSICAL SOC
Ross Maspero, Stephen Sweeney, Marian Florescu (2016)Unfolding the band structure of GaAsBi, In: Journal of Physics: Condensed Matter29(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%.

M Florescu, S John (2001)Single-atom switching in photonic crystals, In: Physical Review A. Atomic, Molecular, and Optical Physics64(3)pp. 033801/1-033801/21 American Physical Society
M Florescu, K Busch, JP Dowling (2007)Thermal radiation in photonic crystals, In: PHYSICAL REVIEW B75(20)ARTN 2pp. ?-? AMERICAN PHYSICAL SOC
W Man, M Florescu, M Matsuyama, P Yadak, G Nahal, S Hamshezad, E Williamson, P Steinhardt, S Torquato, P Chaikin (2013)Photonic band gap in isotropic hyperuniform disordered solids with low dielectric contrast, In: Optics Express21(17)pp. 19972-19981
M Florescu, W Man, RA Mullen, M Milosevic, T Amoah, PM Chaikin, S Torquato, P Steinhardt (2014)Isotropic band gaps, optical cavities, and freeform waveguides in hyperuniform disordered photonic solids, In: Proc. SPIE 9162, Active Photonic Materials VI, 91620G (September 12, 2014)
Izabela Jurewicz, Alice A.K King, Ravi Shanker, Matthew J. Large, Roman J. Smith, Ross Maspero, Sean P. Ogilvie, Jurgen Scheerder, Jun Han, Claudia Backes, Joe Razal, Marian Florescu, Joseph Keddie, Jonathan N. Coleman, Alan Dalton (2020)Mechanochromic and Thermochromic Sensors Based on Graphene Infused Polymer Opals, In: Advanced Functional Materials30(31) Wiley

High quality opal-like photonic crystals containing graphene are fabricated using evaporation-driven self-assembly of soft polymer colloids. A miniscule amount of pristine graphene within a colloidal crystal lattice results in the formation of colloidal crystals with a strong angle-dependent structural color and a stop band that can be reversibly shifted across the visible spectrum. The crystals can be mechanically deformed or can reversibly change color as a function of their temperature, hence their sensitive mechanochromic and thermochromic response make them attractive candidates for a wide range of visual sensing applications. In particular, we show that the crystals are excellent candidates for visual strain sensors or integrated time-temperature indicators which act over large temperature windows. Given the versatility of these crystals, this method represents a simple, inexpensive and scalable approach to produce multifunctional graphene infused synthetic opals and opens up exciting applications for novel solution-processable nanomaterial based photonics.

M Florescu, S Torquato, PJ Steinhardt (2009)Designer disordered materials with large, complete photonic band gaps., In: Proc Natl Acad Sci U S A106(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.

M Castro-Lopez, M Gaio, Steven Sellers, Georgios Gkantzounis, Marian Florescu, R Sapienza (2017)Reciprocal space engineering with hyperuniform gold disordered surfaces, In: APL Photonics2(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.

M Florescu, S Torquato, PJ Steinhardt (2009)New classes of non-crystalline photonic band gap materials, In: Proccedings of The European Conference on Lasers and Electro-Optics and the XIth European Quantum Electronics Conference
Marian Florescu, S Scheel, PL Knight, H Lee, JP Dowling (2006)Nonlinear tuning of 3D photonic band-gap structures for single-photon on demand sources, In: Physica E: Low-Dimensional Systems and Nanostructures32(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 μ m. © 2006 Elsevier B.V. All rights reserved.

M Florescu, H Lee, I Puscasu, M Pralle, L Florescu, DZ Ting, JP Dowling (2007)Improving solar cell efficiency using photonic band-gap materials, In: SOLAR ENERGY MATERIALS AND SOLAR CELLS91(17)pp. 1599-1610 ELSEVIER SCIENCE BV
M Florescu, S Torquato, PJ Steinhardt (2009)Complete band gaps in two-dimensional photonic quasicrystals, In: PHYSICAL REVIEW B80(15)ARTN 1pp. ?-? AMER PHYSICAL SOC
FM Spedalieri, H Lee, M Florescu, KT Kapale, U Yurtsever, JP Dowling (2004)Exploiting the quantum Zeno effect to beat photon loss in linear optical quantum information processors, In: 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.

Marian Florescu, S Torquato, PJ Steinhardt (2010)Effects of random link removal on the photonic band gaps of honeycomb networks, In: APPLIED PHYSICS LETTERS97(20)201103 AMER INST PHYSICS
Georgios Gkantzounis, Marian Florescu (2017)Freeform Phononic Waveguides, In: Crystals7(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.

S John, M Florescu (2001)Photonic bandgap materials: towards an all-optical micro-transistor, In: JOURNAL OF OPTICS A-PURE AND APPLIED OPTICS3(6)pp. S103-S120 IOP PUBLISHING LTD
MM Milošević, M Florescu, W Man, PJ Steinhardt, S Torquato, PM Chaikin, T Amoah, G Nahal, RA Mullen (2014)Silicon waveguides and filters in hyperuniform disordered photonic solids for the near-infrared, In: 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.

A Utgenannt, Ross Maspero, Andrea Fortini, R Turner, Marian Florescu, Christopher Jeynes, AG Kanaras, OL Muskens, Richard Sear, Joseph Keddie (2016)Fast Assembly of Gold Nanoparticles in Large-Area 2-D Nanogrids Using a One-Step, Near-Infrared Radiation-Assisted Evaporation Process, In: ACS Nano10(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.

R Maspero, SJ Sweeney, M Florescu (2013)Modelling the Auger Recombination rates of GaAs(1-x)Bi x alloys, In: 13th International Conference on Numerical Simulation of Optoelectronic Devices, NUSOD 2013pp. 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 ∼11% Bismuth. © 2013 IEEE.

Steven Sellers, W Man, S Sahba, Marian Florescu (2017)Local self-uniformity in photonic networks, In: Nature Communications814439 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.

Georgios Gkantzounis, Timothy Amoah, Marian Florescu (2017)Hyperuniform disordered phononic structures, In: Physical Review B95(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.

MM Milošević, M Florescu, T Amoah, W Man, G Nahal, PJ Steinhardt, S Torquato, PM Chaikin, RA Mullen (2014)Silicon waveguides and filters in hyperuniform disordered photonic solids for the near-infrared, In: 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.

Marian Florescu, Nicoletta Granchi, Francesca Intonti, Pedro David García, Massimo Gurioli, Guillermo Arregui (2023)Q-Factor Optimization of Modes in Ordered and Disordered Photonic Systems Using Non-Hermitian Perturbation Theory, In: ACS Photonics American Chemical Society

The quality factor, Q, of photonic resonators permeates most figures of merit in applications that rely on cavity-enhanced light–matter interaction such as all-optical information processing, high-resolution sensing, or ultralow-threshold lasing. As a consequence, large-scale efforts have been devoted to understanding and efficiently computing and optimizing the Q of optical resonators in the design stage. This has generated large know-how on the relation between physical quantities of the cavity, e.g., Q, and controllable parameters, e.g., hole positions, for engineered cavities in gaped photonic crystals. However, such a correspondence is much less intuitive in the case of modes in disordered photonic media, e.g., Anderson-localized modes. Here, we demonstrate that the theoretical framework of quasinormal modes (QNMs), a non-Hermitian perturbation theory for shifting material boundaries, and a finite-element complex eigensolver provide an ideal toolbox for the automated shape optimization of Q of a single photonic mode in both ordered and disordered environments. We benchmark the non-Hermitian perturbation formula and employ it to optimize the Q-factor of a photonic mode relative to the position of vertically etched holes in a dielectric slab for two different settings: first, for the fundamental mode of L3 cavities with various footprints, demonstrating that the approach simultaneously takes in-plane and out-of-plane losses into account and leads to minor modal structure modifications; and second, for an Anderson-localized mode with an initial Q of 200, which evolves into a completely different mode, displaying a threefold reduction in the mode volume, a different overall spatial location, and, notably, a 3 order of magnitude increase in Q.

Nasim Tavakoli, RICHARD JOHN SPALDING, Alexander Lambertz, Pepijn Koppejan, Georgios Gkantzounis, Chenglong Wan, Ruslan Röhrich, Evgenia Kontoleta, A. Femius Koenderink, Riccardo Sapienza, MARIAN FLORESCU, Esther Alarcon-Llado (2022)Over 65% Sunlight Absorption in a 1 μm Si Slab with Hyperuniform Texture, In: ACS photonics9(4)pp. 1206-1217 American Chemical Society

Thin, flexible, and invisible solar cells will be a ubiquitous technology in the near future. Ultrathin crystalline silicon (c-Si) cells capitalize on the success of bulk silicon cells while being lightweight and mechanically flexible, but suffer from poor absorption and efficiency. Here we present a new family of surface texturing, based on correlated disordered hyperuniform patterns, capable of efficiently coupling the incident spectrum into the silicon slab optical modes. We experimentally demonstrate 66.5% solar light absorption in free-standing 1 μm c-Si layers by hyperuniform nanostructuring for the spectral range of 400 to 1050 nm. The absorption equivalent photocurrent derived from our measurements is 26.3 mA/cm2, which is far above the highest found in literature for Si of similar thickness. Considering state-of-the-art Si PV technologies, we estimate that the enhanced light trapping can result in a cell efficiency above 15%. The light absorption can potentially be increased up to 33.8 mA/cm2 by incorporating a back-reflector and improved antireflection, for which we estimate a photovoltaic efficiency above 21% for 1 μm thick Si cells.

Nicoletta Granchi, RICHARD JOHN SPALDING, Matteo Lodde, Maurangelo Petruzzella, Frank W. Otten, Andrea Fiore, Francesca Intonti, Riccardo Sapienza, MARIAN FLORESCU, Massimo Gurioli (2022)Near-Field Investigation of Luminescent Hyperuniform Disordered Materials, In: Advanced optical materials2102565 Wiley

Disordered photonic nanostructures have attracted tremendous interest in the past three decades, not only due to the fascinating and complex physics of light transport in random media, but also for peculiar functionalities in a wealth of interesting applications. Recently, the interest in dielectric disordered systems has received new inputs by exploiting the role of long-range correlation within scatterer configurations. Hyperuniform photonic materials, that share features of photonic crystals and random systems, constitute the archetype of systems where light transport can be tailored from diffusive transport to a regime dominated by light localization due to the presence of photonic band gap. Here, advantage is taken of the combination of the hyperuniform disordered (HuD) design in slab photonics, the use of embedded quantum dots for feeding the HuD resonances, and near-field hyperspectral imaging with sub-wavelength resolution in the optical range to explore the transition from localization to diffusive transport. It is shown, theoretically and experimentally, that photonic HuD systems support resonances ranging from strongly localized modes to extended modes. It is demonstrated that Anderson-like modes with high Q/V are created, with small footprint, intrinsically reproducible and resilient to fabrication-induced disorder, paving the way for a novel photonic platform for quantum applications.

N Granchi, M Lodde, K Stokkereit, R Spalding, P van Veldhoven, R Sapienza, A Fiore, M Gurioli, M Florescu, F Intonti (2023)Near-field imaging of optical nano-cavities in Hyperuniform disordered materials, In: PHYSICAL REVIEW B107064204 APS

Hyperuniform disordered photonic materials have recently been shown to display large, complete photonic band gaps and isotropic optical properties, and are emerging as strong candidates for a plethora of optoelectronic applications, making them competitive with many of their periodic and quasiperiodic counterparts. In this work, high quality factor optical cavities in hyperuniform disordered architectures are fabricated through semiconductor slabs and experimentally addressed by scanning near-field optical microscopy. The wide range of confined cavity modes that we detect arise from carefully designed local modifications of the dielectric structure. Previous works on hyperuniform disordered photonic systems have previously identified several Anderson localized states spectrally located at the PBG edges with relatively high quality factors. In this work, by engineering the structural parameters of the cavity, we achieve an experimental quality factor of order 6000 (higher than the one of the Anderson states) and we demonstrate that three types of localized modes of different nature coexist within a small area and in a relatively narrow spectral window of the disordered correlated system. Their compatibility with general boundary constraints, in contrast with ordered architectures that suffer strict layout constraints imposed by photonic crystals' axes orientation, makes optical cavities in disordered hyperuniform patterns a flexible optical insulator platform for planar optical circuits.

Adam Burgess, Marian Florescu (2022)Non-Markovian Dynamics of a Single Excitation within Many-Body Dissipative Systems, In: Physical Review A105062207

We explore the dynamics of $N$ coupled atoms to a generic bosonic reservoir under specific system symmetries. In the regime of multiple atoms coupled to a single reservoir with identical couplings, we identify remarkable effects, notably that the initial configuration of the atomic excited state amplitudes strongly impacts the dynamics of the system and can even fully sever the system from its environment. Additionally, we find that steady state amplitudes of the excited states become independent of the choice of the reservoir. The framework introduced is applied to a structured photonic reservoir associated with a photonic crystal, where we show it reproduces previous theoretical and experimental results and it predicts superradiant behaviour within the single-excitation regime.

Mira Naftaly, Gian Savvides, Fawwaz Alshareef, Patrick Flanigan, GianLuc Lui, Marian Florescu, Ruth Ann Mullen (2022)Non-Destructive Porosity Measurements of 3D Printed Polymer by Terahertz Time-Domain Spectroscopy, In: Applied Sciences12(2)927 MDPI

The porosity and inhomogeneity of 3D printed polymer samples were examined using terahertz time-domain spectroscopy, and the effects of 3D printer settings were analysed. A set of PETG samples were 3D printed by systematically varying the printer parameters, including layer thickness, nozzle diameter, filament (line) thickness, extrusion, and printing pattern. Their effective refractive indices and loss coefficients were measured and compared with those of solid PETG. Porosity was calculated from the refractive index. A diffraction feature was observed in the loss spectrum of all 3D printed samples and was used as an indication of inhomogeneity. A “sweet spot” of printer settings was found, where porosity and inhomogeneity were minimised.

Adam Burgess, Marian Florescu (2021)Modelling non-Markovian dynamics in photonic crystals with recurrent neural networks, In: Optical materials express11(7)pp. 2037-2048

We develop a recurrent neural network framework to model the non-Markovian dynamics exhibited by two-level atoms interacting with the radiation reservoir of a photonic crystal. Despite the strong non-Markovianity of the atomic dynamics induced by the rapid spectral variation in photonic density of states of the photonic reservoir, our recurrent neural network approach is able to capture precise details in the atomic evolution, including the fractional steady-state atomic population inversion and spectral splitting of the atomic transition. We demonstrate the robustness of the recurrent neural network setup against reduced data sets and its effectiveness to deal with systems of increased complexity.

MARIAN FLORESCU, Florescu Marian, Torquato Salvatore, Steinhardt Paul J (2011)Non-crystalline materials having complete photonic, electronic or phononic bandgaps

The invention provides an article of manufacture, and methods of designing and making the article. The article permits or prohibits waves of energy, especially photonic/electromagnetic energy, to propagate through it, depending on the energy band gaps built into it. The structure of the article may be reduced to a pattern of points having a hyperuniform distribution. The point-pattern may exhibit a crystalline symmetry, a quasicrystalline symmetry or may be aperiodic. In some embodiments, the point pattern exhibits no long-range order. Preferably, the point-pattern is isotropic. In all embodiments, the article has a complete, TE- and TM-optimized band-gap. The extraordinary transmission phenomena found in the disordered hyperuniform photonic structures of the invention find use in optical micro-circuitry (all-optical, electronic or thermal switching of the transmission), near-field optical probing, thermophotovoltaics, and energy-efficient incandescent sources.

MARIAN FLORESCU, Mullen Ruth Ann, Florescu Marian, Amoah Timothy, Milosevic Milan M (2016)Hyperuniform disordered material with perforated resonant structure

An optical structure includes a Hyperuniform Disordered Solid ("HUDS") structure, a photonic crystal waveguide, and a perforated resonant structure. The HUDS structure is formed by walled cells organized in a lattice. The photonic crystal waveguide is configured to guide an optical signal and includes an unperforated central strip extended lengthwise and three rows of circular perforations disposed on each side of the unperforated central strip. The perforated resonant structure is formed along a boundary of the photonic crystal waveguide. The perforated resonant structure is configured to be resonant at a frequency band that is a subset of a bandwidth of the optical signal. The perforated resonant structure includes an outer segment, a middle segment, and an inner segment of the circular perforations that are offset away from the unperforated central strip at a first, second, and third offset distance.

The invention provides a composition comprising a three-dimensional amorphous trivalent network which reduces the number of modes within a particular frequency range (ωc±Δω). The invention also extends to use of the composition as a structural colouration material and a paint, dye or fabric comprising the structural colouration material. Additionally, the invention extends to use of the composition as an optical filter or as a supporting matrix configured to define at least one optical component, such as a frequency filter, light-guiding structure for a telecommunications application, an optical computer chip, an optical micro-circuit or a laser comprising the supporting matrix.

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.

M Florescu, S Dickman, M Ciorga, A Sachrajda, P Hawrylak (2004)Spin-orbit interaction and spin relaxation in a lateral quantum dot, In: PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES22(1-3)pp. 414-417
M Florescu, S Torquato, P Steinhardt (2012)Photonic Band Gaps and Unusual Photon Transport in Hyperuniform Disordered Structures, In: Frontiers in Optics 2012/Laser Science XXVIII, OSA Technical Digest (online)pp. FTh3F.5-?

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.

S Tsitrin, Y He, S Hewatt, B Leung, W Man, M Florescu, PJ Steinhardt, S Torquato, P Chaikin (2012)Cavity Modes Study in Hyperuniform Disordered Photonic Bandgap Materials, In: Frontiers in Optics 2012/Laser Science XXVIII, OSA Technical Digest (online)pp. FTh3F.4.-?

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.

WN Man, Marian Florescu, K Matsuyama, P Yadak, S Torquato, P Steinhardt, P Chaikin (2010)Experimental observation of photonic bandgaps in hyperuniform disordered material, In: 2010 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO) AND QUANTUM ELECTRONICS AND LASER SCIENCE CONFERENCE (QELS)
W Man, Marian Florescu, S Hashemizad, Y He, R Leung, E Williamson, P Chaikin (2012)Experimental demonstration of guiding, bending, and filtering of electromagnetic wave in disordered photonic band gap materials, In: 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.

M Florescu, S Scheel, H Lee, PL Knight, JP Bowling, M Marciniak (2006)Three-dimensional photonic band-gap structures for single-photon on demand sources, In: ICTON 2006: 8th International Conference on Transparent Optical Networks, Vol 2, Proceedingspp. 40-43
M Florescu, K Busch (2009)Properties of thermal radiation in photonic crystals, In: JOURNAL OF OPTICS A-PURE AND APPLIED OPTICS11(11)pp. ?-?
Marian Florescu, S Scheel, H Lee, PL Knight, JP Dowling (2006)Nonlinear tuning of 3D photonic band-gap structures for single-photon on demand sources, In: PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES32(1-2)pp. 484-487 Elsevier
M Florescu, S John (2001)Single-atom switching in photonic crystals, In: PHYS REV A6403(3)033801pp. ?-? AMERICAN PHYSICAL SOC
CJ Schuler, C Wolff, K Busch, M Florescu (2010)Thermal emission from finite photonic crystals, In: GS Subramania, S Foteinopoulou (eds.), ACTIVE PHOTONIC MATERIALS III7756
Marian Florescu (2020)Freeform Phononic Waveguides University of Surrey
M Florescu, H Lee, JP Dowling (2005)On the emission and absorption of thermal radiation in photonic crystals, In: 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.

M Florescu, S John (2002)All-optical transistor action in photonic band gap materials, In: RA Lessard, GA Lampropoulos, GW Schinn (eds.), APPLICATIONS OF PHOTONIC TECHNOLOGY 54833pp. 513-524
MM Milosevic, M Florescu, W Man, G Nahal, S Tsitrin, T Amoah, PJ Steinhardt, S Torquato, PM Chaikin, RA Mullen (2014)Hyperuniform disordered photonic band gap devices for silicon photonics, In: 2014 IEEE 11TH INTERNATIONAL CONFERENCE ON GROUP IV PHOTONICS (GFP) IEEE
MM Milosˇevic, M Florescu, W Man, PJ Steinhardt, S Torquato, PM Chaikin, T Amoah, G Nahal, RA Mullen (2014)Silicon waveguides and filters in hyperuniform disordered photonic solids for the near-infrared, In: 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.

T Amoah, M Florescu (2015)Flexible cavity and waveguide light confinement in hyperuniform photonic slabs, In: Signal Processing in Photonic Communications, SPPCom 2015pp. 262p-?

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.

T Amoah, M Florescu (2015)Flexible cavity andwaveguide light confinement in hyperuniform photonic slabs, In: Integrated Photonics Research, Silicon and Nanophotonics, IPRSN 2015pp. 371p-?

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.

G Nahal, M Florescu, RA Mullen, P Steinhardt, S Torquato, P Chaikin, W Man (2013)Freeform wave-guiding at infrared regime in two dimensional disordered photonic bandgap materials, In: 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.

T Amoah, M Florescu (2015)Light confinement in hyperuniform photonic slabs: High-Q cavities and low-loss waveguides, In: CLEO: Science and Innovations, CLEO-SI 2015pp. 2267-?

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.

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