Paper by Associate Professor Rasmus E Christiansen and co-authors in Optics Express
Associate Professor Rasmus E Christiansen and co-authors had their paper on "Impact of Figures of Merit in Photonic Inverse Design” published in Optics Express. Through inverse design, they demonstrate that markedly different photonic device geometries are needed to obtain optimal performance for applications with figures of merit of similar structure. Hereby stressing the importance of carefully analyzing, fully understanding and directly targeting the true device application in the inverse design process to obtain the best possible device performance.
Paper in Optica on "Cavity dumping using a microscopic Fano laser"
Postdoc Gaoneng Dong had his paper on "Cavity dumping using a microscopic Fano laser" published in Optica. We demonstrate an ultra-small cavity-dumped microscopic laser based on an optical Fano resonance, which generates optical pulses with peak power more than one order of magnitude higher than the corresponding conventional gain-modulated laser. This demonstration paves the way for realizing microscopic lasers for low-power chip-scale applications. Link to the paper in the comment field.
New members in NanoPhoton
Many new members have joined NanoPhoton in the past dew months. They are Benjamin, Falkenberg Gøtzsche, PhD student, Pawel Holewa, postdoc, Mathias Marchal, PhD student, Adrian Holm Dubré, Research Assistant, and Simon Klinck Borregaard, PhD Student.
New member in NanoPhoton
In January we welcomed our newest member to NanoPhoton, senior researcher Thomas Christensen. Thomas is interested in the realization and manifestations of topological phenomena in photonic systems, especially in symmetry-protected topological phases. His expertise includes photonic crystal design and analysis, light-matter interaction, topological band theory, and group theory.
How to make LinkedIn work for us
In January we received a visit from Zydrune Domarkaite who gave a talk on “LinkedIn – how to make it work for you”. It was a very inspiring and motivating workshop. We hope the result will appear on our LinkedIN profile.
We are the cover story of the new edition of Laser Focus World
In the cover story of the new edition of Laser Focus World, PhD student Marcus Albrechtsen and Associate Professor Søren Stobbe share their thoughts on the perspectives of their recent results on dielectric bowtie cavities.
The new results were obtained in an interdisciplinary and highly collaborative team effort within NanoPhoton - Center for Nanophotonics at DTU - Technical University of Denmark.
Søren Stobbe and his research group's scientific brealthorugh mentioned in the DNRF's newsletter
In their newsletter, The Danish National Research Foundation (DNRF) features an article with NanoPhoton member Søren Stobbe on his research group's recent scientific breakthrough. Congratulations to Søren and his group, and thanks to the DNRF.
New PhD student joining NanoPhoton
On 15 November we welcomed Amedeo Carbone to our centre. We look forward to working with you, Amedeo.
Workshop in NanoPhoton
We at NanoPhoton just held a workshop to get together, present our research, share ideas and strengthen collaboration across the centre. Thank you for the good talks and inspiration!
A feature article in Laser Focus World
The magazine Laser Focus World highlights our recent work on nanometer-scale photon confinement in topology-optimized dielectric cavities in a feature article!
Marco and Kristian participated in the “2022 IEEE Photonics Conference (IPC)” in Vancouver, Canada
Recently, our NanoPhoton members Marco Saldutti and Kristian Seegert took part in the “2022 IEEE Photonics Conference (IPC)” in Vancouver, Canada.
Kristian presented a microscopic laser – a so-called Fano laser – that uses a carefully engineered mirror to generate ultrashort pulses. The compact footprint makes this laser an attractive candidate as an on-chip pulsed light source for photonic integrated circuits.
Marco discussed the use of nonlinear photonic nanocavities with extreme dielectric confinement of light (EDC) for switching applications. The unconventional geometry enhances the diffusion dynamics of electron-hole pairs and allows a significant speed-up of all-optical signal processing functionalities, without compromising energy efficiency.
"Modal properties of dielectric bowtie cavities with deep sub-wavelength confinement"
In a recently published work in Optics Express, we at NanoPhoton - Center for Nanophotonics performed a thorough numerical study of a novel semiconductor device that can squeeze light into the nanoscale with minimal losses, an important step in unlocking future quantum technologies.
Fundmental scientific breakthrough
Researchers from Søren Stobbe's research group have developed a nanostructure which compresses the light so that it becomes 10,000 times thinner than a human hair. This is a fundamental scientific breakthrough and can be important for multiple fields, including energy-efficient computers and quantum technology.
New colleagues joining us
On 1 September and 1 October, respectively, postdoc Alireza Shabani and PhD students Daniel Farbowitz and Sergei Lepeshov joined us at NanoPhoton.
New results with numerous applications published in "Nature Nanotechnology"
A new study led by researchers from the Catalan Institute of Nanoscience and Nanotechnology (ICN2, Barcelona) in collaboration with NanoPhoton researchers show that nanostructures can be engineered to either inhibit or guide mechanical vibrations at hypersonic frequencies. The results, published in the journal ‘Nature Nanotechnology’, could have numerous applications within nanotechnology, quantum computing, optomechanics, signal processing, and biosensors.
Please find the paper here:
https://www.nature.com/articles/s41565-022-01178-1
NanoPhoton is growing
We are very glad to welcome our two new PhD students Beñat Martínez Aguirre de Jokisch and Robin Dahiya who joined NanoPhoton on 1 August.
"Electrically‐Driven Photonic Crystal Lasers with Ultra‐low Threshold" in Laser and Photonic Reviews
The latest issue of Laser and Photonic Reviews features our article titled "Electrically‐Driven Photonic Crystal Lasers with Ultra‐low Threshold" where we experimentally demonstrate a microscopic laser with ultra-low threshold developed at DTU and NanoPhoton - Center for Nanophotonics. The properties of these lasers are investigated, providing new insight into the Quality Factor of the laser cavity, the leakage current, and efficiency.
Paper in Light: Science & Applications
Most theoretical derivations of fundamental radiative processes rely on energetic considerations and detailed balance equations, but not on momentum considerations. In this article we bring momentum exchange processes into consideration. It becomes very tricky in near-zero index (NZI) materials, i.e., materials having a phase refractive index close to zero. We theoretically demonstrate that momentum recoil, transfer momentum from the field to the atom and Doppler shift are inhibited in NZI materials. Fundamental radiative processes inhibition is also explained due to those momentum considerations inside three-dimensional NZI materials. We also discuss implication of NZI properties on consequence on the Heisenberg inequality, microscopy applications and diffraction pattern. Our findings give better understanding of fundamental light-matter interactions at the nanoscale as well as possibility of new lasing applications.
Momentum considerations inside near-zero index materials
Paper published in ACS Photonics
The team of Elizaveta Semenova demonstrated a novel InAs/InP Quantum Dot-based single photon emitter operating at the telecom C-band. A simple vertical emitting device possesses a photon extraction efficiency of ∼10% and high-purity single-photon generation ( g(2)(τ = 0) < 0.02 ) at the liquid helium temperature and preserved up to 50 K.
Bright Quantum Dot Single-Photon Emitters at Telecom Bands Heterogeneously Integrated on Si
Conference on "Fundamentals and applications of semiconductor nanocavities"
Last week NanoPhoton hosted a conference on “Fundamentals and applications of semiconductor nanocavities” with 24 international leading researchers joining for three days of very good and interesting talks and vivid and fruitful discussions. Thank you to all for making it a success.
Three PhD Students join NanoPhoton
Kristian Seegert joined NanoPhoton on 1 March 2022. On 1 April 2022 Alexandra Palici and Frederik Schröder joined the centre. We look forward to the collaboration.
NanoPhoton Lecture: First-principles description of light-matter interactions in 2D materials by Kristian Sommer Thygesen
Kristian Thygesen develops and applies first-principles methods based on density functional theory and many-body perturbation theory to describe the electronic structure of materials with a particular focus on nanostructured and low-dimensional materials. He is also interested in the application of AI and data-driven approaches to materials design.
Two-dimensional (2D) materials, like graphene, hexagonal boron-nitride and the semiconducting transition metal dichalcogenides (TMDs), present exciting opportunities for creating new types of quantum states that can be manipulated with unprecedented accuracy and efficiency. In this talk I will demonstrate how excitons in TMD monolayers may be tuned via dielectric engineering [1] and how (mixed) interlayer excitons in TMD bilayers [2] may be controlled by application of a perpendicular electrical field. The spontaneous radiative emission from electronic transitions in 2D materials can be manipulated by engineering the electromagnetic vacuum field. I will show that record high Purcell enhancements of up to 10^7 can be achieved by coupling intersubband transitions in van der Waals quantum wells to the acoustic plasmons in a graphene sheet [3]. Finally, I will discuss how first-principles calculations can aid the discovery of crystal point defects in wide band gap semiconductors with potential application as single-photon sources, spin qubits or magnetic field sensing [4].
Paper on "Quantum theory of two-dimensional materials coupled to electromagnetic resonators"
Recently published in Physical Review B, NanoPhoton research headed by Emil Denning shows how a series of recent spectacular experiments of strong coupling in systems of two-dimensional materials and nanoscale electromagnetic resonators can be explained by the symmetry-breaking light-matter interaction, which leads to the formation of a localized exciton state. In a companion letter in Physical Review Research, the team analyses the quantum optical properties of the strongly-coupled system, and predicts that polariton blockade due to nonlinear exciton-exciton interactions is well within reach by use of nanoscale resonators, such as the optical cavities designed and fabricated within the NanoPhoton research center.
Phys. Rev. B 105, 085306 (2022) - Quantum theory of two-dimensional materials coupled to electromagnetic resonators (aps.org)
Phys. Rev. Research 4, L012020 (2022) - Cavity-induced exciton localization and polariton blockade in two-dimensional semiconductors coupled to an electromagnetic resonator (aps.org)
NanoPhoton Lecture: III-V semiconductors on silicon hybrid nanophotonics by Fabrice Raineri
Raineri’s research activity is focused on the exploration of the interactions in III-V semiconductor/silicon hybrid photonic crystal (PhC) structures and their exploitation for the achievement of smaller, smarter, faster energy-efficient optoelectronic components which will revolutionize our world, governed by information and communication technology.
His aim is to build a new panel of optoelectronic devices, ultimate in terms of power consumption as well as in speed. His goal too is to trace new paths in nonlinear and quantum optics through the use of unprecedented optical configurations enabled by the hybrid approach. More in detail, he leads his work along three research directions namely, nanolasers, nonlinear nanophotonic devices and parametric nonlinear nanophotonics.
Proof of Concept Grant from the European Research Council (ERC) to demonstrate a new optical receiver for application in integrated photonics
The project, “Fano Detector”, is based on a novel idea of using a photonic Fano resonance to demodulate high-speed coherent signals in an energy-efficient way. The project builds on research results obtained in the ERC Advanced Grant “Fano Photonics”.
Measurement set-up (left) and chip (right) with coherent detector based on Fano interference.
Contacts:
Dr. Dagmawi Alemayehu Bekele
Prof. Jesper Mørk
ERC Press Release
@european-research-council
NanoPhoton paper published in NanoPhotonics
Elizaveta Semenova and Shima Kadkhodazadeh had their paper published in Nanophotonincs: Droplet epitaxy symmetric InAs/InP quantum dots for quantum emission in the third telecom window: morphology, optical and electronic properties.
We provide an analytical model to explain the kinetics of pit formation and QD base shape modification. Our theoretical calculations of electronic states reveal the properties of neutral and charged excitons and biexcitons confined in such QDs, which agree with the optical investigations of individual QDs. The optical response of QDs' ensemble suggests that FSS may indeed be negligible, as reflected in the vanishing degree of linear polarization.
NanoPhoton members to receive grants from the Velux Foundations
We are very proud to announce that two NanoPhoton members have received generous grants from the Velux Foundations. Senior Researcher Yi Yu receives DKK 6 million for his project ‘Nanolaser based on extremely confined nonradiative state (EXTREME)’. Thomas Christensen, who is currently a research scientist at Massachusetts Institute of Technology (MIT), receives DKK 8 million for his project 'Symmetry-guided discovery of topological photonics'.
PhD Student joins NanoPhoton
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We are very happy that Alisha Nanwani, PhD Student, joined NanoPhoton on 15 January 2022.
Alisha's project deals with selective epitaxy of III-V/Si nanostructures for extreme dielectric confinement of light.
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Postdoc joins NanoPhoton
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We are very glad to welcome Yury Berdnikov, Postdoc, who joined NanoPhoton on 15 January 2022.
Yury's work is in between the nanofabrication in WP 4 and optoelectronic devices in WP 2. I investigate the ways for surface states passivation aiming to improve the optical performance of the structures with EDC cavities.
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Postdoc joins NanoPhoton
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We are very pleased to announce that Mohammad Abutoama, postdoc, joined NanoPhoton on 15 December 2021.
Mohammad's research is focused on the interaction between colloidal Nanocrystal Quantum Dots (NQDs) and EDC cavities, including theoretical modeling, design and experimental realization of the light-matter interaction in NQDs-EDC nanostructures for proposing efficient single photon sources.
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Yi Yu's paper published in Optica
Yi had his paper "Remote excitation between quantum emitters mediated by an optical Fano resonance" published in Optica.
We demonstrate remote coupling between two site-controlled semiconductor quantum dot emitters mediated by an optical Fano resonance induced by coupling cavity modes via a continuum waveguide state. Unlike ordinary coupled modes, the Fano mode offers both a spatially extended field and a high local density of optical states at the emitters, enhancing light–matter interaction.
NanoPhoton at MNE 2021 in Turin, Italy
NanoPhoton was represented at the "Micro and Nano Engineering Conference” (mne2021.org) in Turin, Italy by members Søren Stobbe, Ali Nawaz Babar, Marcus Albrechtsen and Søren Engelberth Hansen, seen here with DTU colleague Christian Anker Rosiek. The team presented recent work on Casimir forces in nanostructures, photonic topological insulators, and cavities with extreme dielectric confinement.
Paper on "Ultra-coherent Fano laser based on a bound state in the continuum" in Nature Photonics
In a recent paper in Nature Photonics, "Ultra-coherent Fano laser based on a bound state in the continuum", we show how a bound state in the continuum can be used to reduce the spectral linewidth of microlasers significantly. The microscopic laser developed at DTU Fotonik and NanoPhoton - Center for Nanophotonics prove to have fundamental advantages compared to other lasers. Please, find the paper here.
NanoPhoton Lecture: Mesoscopic electrodynamics at metal surfaces: quantum and nonlocal effects by N. Asger Mortensen
Plasmonic phenomena in metals are commonly explored within the framework of classical electrodynamics and semiclassical models for the interactions of light with free-electron matter. The more detailed understanding of mesoscopic electrodynamics at metal surfaces is, however, becoming increasingly important for both fundamental developments in quantum plasmonics [1] and potential applications in emerging light-based quantum technologies [2]. While this intuitively calls for a full quantum description of plasmon-enhanced light-matter interactions, recent discoveries suggest how classical electrodynamics may still suffice if appropriately dressed by quantum-corrected mesoscopic boundary conditions – surface-response formalism. The colloquium will address three cases, where mesoscopic electrodynamic effects matter: 1) plasmon-emitter interactions [3], electronic surface states in crystalline materials [4], and plasmon-polariton interactions in graphene-on-metal structures [5]. Finally, prospects for probing electrodynamics of correlated electron materials are discussed [6].
References
[1] N.A. Mortensen, “Mesoscopic electrodynamics at metal surfaces – From quantum-corrected hydrodynamics to microscopic surface-response formalism”, Nanophotonics 10, 2563 (2021). [2] A.I. Fernández-Domínguez, S.I. Bozhevolnyi & N.A. Mortensen, “Plasmon-enhanced generation of non-classical light”, ACS Photonics 5, 3447 (2018). [3] P.A.D. Gonçalves et al., ”Plasmon-Emitter Interactions at the Nanoscale”, Nat. Commun. 11, 366 (2020). [4] A.R. Echarri et al., "Optical response of noble metal nanostructures: Quantum surface effects in crystallographic facets", Optica 8, 710 (2021). [5] P.A.D. Gonçalves et al., Quantum Surface-Response of Metals Revealed by Acoustic Graphene Plasmons", Nat. Commun. 12, 3271 (2021).
[6] A.T. Costa et al., "Harnessing Ultra-confined Graphene Plasmons to Probe the Electrodynamics of Superconductors", PNAS 118, e2012847118 (2021).
Tutorial papers in Top Downloads list for JOSA B
We are proud to see that our tutorial papers on inverse design in photonics by topology optimization jumped to the top of the Top Downloads list for JOSA B upon publication and remain on the list ten months later.
Utilize topology optimization to design an optical metalens, a demultiplexer or a plasmonic reflector, either by the click of a button in COMSOL Multiphysics https://doi.org/10.1364/JOSAB.406048 or via a compact 200 line MATLAB code https://doi.org/10.1364/JOSAB.405955.
Modal Properties of Photonic Crystal Cavities and Applications to Lasers
We have reviewed the properties of the resonant modes of photonic crystal cavities with a special focus on line-defect cavities and applications to ultra-small and energy-efficient semiconductor lasers including slow-light photonic crystal lasers and Fano lasers. We have also covered emerging cavities for extreme dielectric confinement, which promise extremely strong light–matter interactions with deep sub-wavelength mode size and a high quality factor.
You will find the paper here.
Official opening of NanoPhoton
We are very pleased to share some photos from the official opening ceremony of NanoPhoton - Center for Nanophotonics led by Prof. Jesper Mørk. It was a long-awaited and festive event. We extend our thanks to the Chairman of the Board of the Danmarks Grundforskningsfond/The Danish National Research Foundation, Prof. Jens Kehlet Nørskov, and the President of DTU, Prof. Anders Overgaard Bjarklev, for inspiring and supportive opening speeches. We also thank our collaborators and all of you who took the time to celebrate this wonderful occasion with us.
President of DTU, Prof. Anders Overgaard Bjarklev and
Center Leader of NanoPhoton, Prof. Jesper Mørk
Participants in the official opening of NanoPhoton
Jesper Mørk, Palle Jeppesen and Bjarne Tromborg
Members of NanoPhoton
Postdoc joins NanoPhoton
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We are pleased to announce that Ayman Nassar Kamel, Postdoc, joined NanoPhoton on 1 October.
Ayman works on the integration of EDC cavities with nano-electronic devices with a vision of providing a platform for sub-femto-joule-per-bit interconnects. He has experience in non-linear integrated optics and interface physics, both of which are useful for such nano-optoelectronic devices we hope to realize.
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PhD Student joins NanoPhoton
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We are pleased to announce that Maria Vittoria Gurrieri,
PhD Student, joined NanoPhoton on 1 October.
Maria Vittoria works on the development of theoretical
models for light-matter interaction in EDC-structures.
Her research is focused on the investigation of such
interaction in optical nanocavities coupled with 2D
materials.
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NanoPhoton Lecture: Single-photon quantum hardware: towards scalable photonic quantum technology with a quantum advantage by Peter Lodahl
Quantum dots embedded in photonic nanostructures offer a highly efficient and coherent deterministic photon-emitter interface [1]. It constitutes an on-demand single-photon source for quantum-information applications, enables single-photon nonlinear, optics and the constructing of deterministic quantum gates for photons [2]. We review recent experimental progress, and demonstrate that the current technology can be scaled up to reach quantum advantage [3] with the demonstration of near-transform-limited emitters in high-cooperativity planar nanophotonic waveguides [4]. The coherent control of a single spin in the quantum dot [5, 6] offers additional opportunities of generating advanced multi-photon entangled states [7]. We discuss potential applications of these novel deterministic photonic hardware in quantum computing and quantum communication [8], e.g., for constructing a resource efficient one-way quantum repeater [9].
References
[1] Lodahl et al., Rev. Mod. Phys. 87, 347 (2015). [2] Lodahl, Quantum Science and Technology 3, 013001 (2018). [3] Uppu et al., Science Advances 6, eabc8268 (2020). [4] Pedersen et al., ACS Photonics (2020). [5] Javadi et al., Nature Nanotechnology 13, 398 (2018). [6] Appel et al., Phys. Rev. Lett. 126, 013602 (2021). [7] Tiurev et al., Arxiv: 2007.09295. [8] Uppu et al., Arxiv: 2103.01110. [9] Borregaard et al., Phys. Rev. X 10, 021071 (2020).
NanoPhoton Lecture: From Photonic Crystals to Topological Nanophotonics by Masaya Notomi
NanoPhoton Lecture: Prospects and limitations of atomically thin semiconductors as laser gain material by Christopher Gies
NanoPhoton Lecture:Non-Radiating Electromagnetic Sources by Sergey I. Bozhevolnyi