Imperial College London

Professor Ortwin Hess

Faculty of Natural SciencesDepartment of Physics

Academic Visitor
 
 
 
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Contact

 

+44 (0)20 7594 7586o.hess Website

 
 
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Location

 

806Blackett LaboratorySouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
to

421 results found

Xiong X, Clarke D, Lai Y, Bai P, Png CE, Wu L, Hess Oet al., 2023, Substrate engineering of plasmonic nanocavity antenna modes., Opt Express, Vol: 31, Pages: 2345-2358

Plasmonic nanocavities have emerged as a promising platform for next-generation spectroscopy, sensing and photonic quantum information processing technologies, benefiting from a unique confluence of nanoscale compactness and integrability, ultrafast functionality and room-temperature viability. Harnessing their unprecedented optical field confinement and enhancement properties for such diverse application domains, however, demands continued innovation in cavity design and robust strategies for engineering their plasmonic mode characteristics, with the aim of optimizing spatial and spectral matching conditions for strong light-matter interaction involving embedded quantum emitters. Adopting the canonical gold bowtie nanoantenna, we show that the complex refractive index, n + ik, of the substrate material provides additional design flexibility in tailoring the properties of plasmonic nanocavity modes, including their resonance wavelengths, hotspot locations, intracavity field polarization and radiative decay rates. In particular, we predict that highly refractive (n ≥ 4) or highly absorptive (k ≥ 4) substrates provide two complementary approaches to engineering nanocavity modes that are especially desirable for coupling two-dimensional quantum materials, featuring namely an elevated hotspot with a dominantly in-plane polarized near-field, as well as a strongly radiative character. Our study elucidates the benefits and intricacies of a largely unexplored facet of nanocavity mode manipulation, beyond the widely practiced synthetic control over the cavity topology or physical dimensions, and paves the way for plasmonic cavity quantum electrodynamics with two-dimensional excitonic matter.

Journal article

Groll D, Paschen F, Machnikowski P, Hess O, Wigger D, Kuhn Tet al., 2023, How to Read Out the Phonon Number Statistics via Resonance Fluorescence Spectroscopy of a Single-Photon Emitter, Advanced Quantum Technologies

In today's development of quantum technologies a hybrid integration of phononic excitations becomes increasingly attractive. As natural quasi-particle excitations in solid state systems, phonons couple to virtually any other excitation and therefore constitute a useful interaction channel between different building blocks in hybrid quantum systems. This work explores how the efficient light-scattering properties of a single-photon emitter and the appearance of characteristic sidebands in resonance fluorescence spectra, when interfaced with an arbitrary phonon quantum state, can be utilized for acousto-optical transduction. Within reasonable approximations, an analytical description for the optical spectra in the low excitation limit is developed which can be used to read the number statistics of the initial phonon state from a given spectrum. It is shown that the readout is faulty in situations where relevant resonant transitions are forbidden due to vanishing Franck–Condon factors, especially when considering spectra with a noisy background. Two possible solutions to this problem are presented: (A) changing the detuning of the laser relative to the single-photon emitter which modifies the relevant resonant transitions, or (B) increasing dissipation of the single-photon emitter to promote off-resonant transitions.

Journal article

Bello FD, Clarke DDA, Tarasenko I, Donegan JF, Hess Oet al., 2022, Nanoheating and Nanoconduction with Near-Field Plasmonics: Prospects for Harnessing the Moire and Seebeck Effects in Ultrathin Films, ADVANCED OPTICAL MATERIALS, Vol: 10, ISSN: 2195-1071

Journal article

Xiong X, Lai Y, Clarke D, Kongsuwan N, Dong Z, Bai P, Png CE, Wu L, Hess Oet al., 2022, Control of Plexcitonic Strong Coupling via Substrate-Mediated Hotspot Nanoengineering, ADVANCED OPTICAL MATERIALS, Vol: 10, ISSN: 2195-1071

Journal article

Kim K, Bittner S, Jin Y, Zeng Y, Guazzotti S, Hess O, Wang QJ, Cao Het al., 2022, Sensitive control of broad-area semiconductor lasers by cavity shape, APL PHOTONICS, Vol: 7, ISSN: 2378-0967

Journal article

Bello FD, Kongsuwan N, Hess O, 2022, Near-Field Generation and Control of Ultrafast, Multipartite Entanglement for Quantum Nanoplasmonic Networks, NANO LETTERS, Vol: 22, Pages: 2801-2808, ISSN: 1530-6984

Journal article

Tufarelli T, Friedrich D, Gross H, Hamm J, Hess O, Hecht Bet al., 2021, Single quantum emitter Dicke enhancement, PHYSICAL REVIEW RESEARCH, Vol: 3

Journal article

Kim K, Bittner S, Zeng Y, Guazzotti S, Hess O, Wang QJ, Cao Het al., 2021, Highly parallel ultra-fast random number generation from a stable-cavity broad-area semiconductor laser

Fast and reliable random number generation (RNG) is a key requirement for, e.g., secure telecommunication or quantum simulations. This has driven the development of physical random number generators to replace deterministic, pseudo-random number generators. Semiconductor lasers exhibiting chaotic dynamics induced for example by optical feedback [1] can provide up to 1 Tbit/s, but their speed is ultimately limited by the time scales of the laser dynamics. Parallel RNG via spatial or spectral multiplexing can further increase the speed but previous demonstrations were limited by low intrinsic speed or a small number of channels.

Conference paper

Xiong X, Kongsuwan N, Lai Y, Png CE, Wu L, Hess Oet al., 2021, Room-temperature plexcitonic strong coupling: Ultrafast dynamics for quantum applications, APPLIED PHYSICS LETTERS, Vol: 118, ISSN: 0003-6951

Journal article

Lan H-Y, Hsieh Y-H, Chiao Z-Y, Jariwala D, Shih M-H, Yen T-J, Hess O, Lu Y-Jet al., 2021, Gate-Tunable Plasmon-Enhanced Photodetection in a Monolayer MoS2 Phototransistor with Ultrahigh Photoresponsivity, NANO LETTERS, Vol: 21, Pages: 3083-3091, ISSN: 1530-6984

Journal article

Kim K, Bittner S, Zeng Y, Guazzotti S, Hess O, Wang QJ, Cao Het al., 2021, Massively parallel ultrafast random bit generation with a chip-scale laser, SCIENCE, Vol: 371, Pages: 948-+, ISSN: 0036-8075

Journal article

Roman Castellanos L, Hess O, Lischner J, 2021, Dielectric engineering of hot carrier generation by quantized plasmons in embedded silver nanoparticles, The Journal of Physical Chemistry C: Energy Conversion and Storage, Optical and Electronic Devices, Interfaces, Nanomaterials, and Hard Matter, Vol: 125, Pages: 3081-3087, ISSN: 1932-7447

Understanding and controlling properties of plasmon-induced hot carriers is a key step toward next-generation photovoltaic and photocatalytic devices. Here, we uncover a route to engineering hot-carrier generation rates of silver nanoparticles by designed embedding in dielectric host materials. Extending our recently established quantum-mechanical approach to describe the decay of quantized plasmons into hot carriers we capture both external screening by the nanoparticle environment and internal screening by silver d-electrons through an effective electron–electron interaction. We find that hot-carrier generation can be maximized by engineering the dielectric host material such that the energy of the localized surface plasmon coincides with the highest value of the nanoparticle joint density of states. This allows us to uncover a path to control the energy of the carriers and the amount produced, for example, a large number of relatively low-energy carriers are obtained by embedding in strongly screening environments.

Journal article

Bello F, Kongsuwan N, Donegan JF, Hess Oet al., 2020, Controlled Cavity-Free, Single-Photon Emission and Bipartite Entanglement of Near-Field-Excited Quantum Emitters, NANO LETTERS, Vol: 20, Pages: 5830-5836, ISSN: 1530-6984

Journal article

Kamp M, de Nijs B, Kongsuwan N, Saba M, Chikkaraddy R, Readman CA, Deacon WM, Griffiths J, Barrow SJ, Ojambati OS, Wright D, Huang J, Hess O, Scherman OA, Baumberg JJet al., 2020, Cascaded nanooptics to probe microsecond atomic-scale phenomena, PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, Vol: 117, Pages: 14819-14826, ISSN: 0027-8424

Journal article

Kim K, Bittner S, Zeng Y, Guazzotti S, Hess O, Wang QJ, Cao Het al., 2020, Spatio-Temporal Dynamics of Highly Multimode Semiconductor Lasers, ISSN: 1092-8081

We present a cavity design for broad-area semiconductor lasers that stabilizes lasing dynamics and produces directional emission. By tuning the cavity geometry, we control nonlinear interactions of the lasing modes with the gain medium.

Conference paper

Castellanos LR, Kahk JM, Hess O, Lischner Jet al., 2020, Generation of plasmonic hot carriers from d-bands in metallic nanoparticles, Journal of Chemical Physics, Vol: 152, ISSN: 0021-9606

We present an approach to master the well-known challenge of calculating the contribution of d-bands to plasmon-induced hot carrier rates in metallic nanoparticles. We generalize the widely used spherical well model for the nanoparticle wavefunctions to flat d-bands using the envelope function technique. Using Fermi’s golden rule, we calculate the generation rates of hot carriers after the decay of the plasmon due to transitions either from a d-band state to an sp-band state or from an sp-band state to another sp-band state. We apply this formalism to spherical silver nanoparticles with radii up to 20 nm and also study the dependence of hot carrier rates on the energy of the d-bands. We find that for nanoparticles with a radius less than 2.5 nm, sp-band state to sp-band state transitions dominate hot carrier production, while d-band state to sp-band state transitions give the largest contribution for larger nanoparticles.

Journal article

Saba M, Wong S, Elman M, Oh SS, Hess Oet al., 2020, Nature of topological protection in photonic spin and valley Hall insulators, PHYSICAL REVIEW B, Vol: 101, ISSN: 2469-9950

Journal article

Horton MJ, Ojambati OS, Chikkaraddy R, Deacon WM, Kongsuwan N, Demetriadou A, Hess O, Baumberg JJet al., 2020, Nanoscopy through a plasmonic nanolens, PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, Vol: 117, Pages: 2275-2281, ISSN: 0027-8424

Journal article

Kongsuwan N, Demetriadou A, Horton M, Chikkaraddy R, Baumberg JJ, Hess Oet al., 2020, Plasmonic Nanocavity Modes: From Near-Field to Far-Field Radiation, ACS PHOTONICS, Vol: 7, Pages: 463-471, ISSN: 2330-4022

Journal article

Wong S, Saba M, Hess O, Oh SSet al., 2020, Gapless unidirectional photonic transport using all-dielectric kagome lattices, PHYSICAL REVIEW RESEARCH, Vol: 2

Journal article

Crai A, Demetriadou A, Hess O, 2020, Electron Beam Interrogation and Control of Ultrafast Plexcitonic Dynamics, ACS Photonics, ISSN: 2330-4022

Journal article

Kim K, Bittner S, Zeng Y, Guazzotti S, Hess O, Wang QJ, Cao Het al., 2020, Spatio-temporal dynamics of highly multimode semiconductor lasers, Conference on Lasers and Electro-Optics (CLEO), Publisher: IEEE, ISSN: 2160-9020

Conference paper

Liu X, Kongsuwan N, Li X, Zhao D, Wu Z, Hess O, Zhang Xet al., 2019, Tailoring the Third-Order Nonlinear Optical Property of a Hybrid Semiconductor Quantum Dot-Metal Nanoparticle: From Saturable to Fano-Enhanced Absorption, JOURNAL OF PHYSICAL CHEMISTRY LETTERS, Vol: 10, Pages: 7594-7602, ISSN: 1948-7185

Journal article

Ren G, Han X, Nguyen TG, Khodasevych I, Hamm JM, Hess O, Tian Y, Mitchell Aet al., 2019, Asymmetric transmission of light in hybrid waveguide-integrated plasmonic crystals on a silicon-on-insulator platform, OPTICS LETTERS, Vol: 44, Pages: 5378-5381, ISSN: 0146-9592

Journal article

Kongsuwan N, Xiong X, Bai P, You J-B, Png CE, Wu L, Hess Oet al., 2019, Quantum plasmonic immunoassay sensing, Nano Letters: a journal dedicated to nanoscience and nanotechnology, Vol: 19, Pages: 5853-5861, ISSN: 1530-6984

Plasmon–polaritons are among the most promising candidates for next-generation optical sensors due to their ability to support extremely confined electromagnetic fields and empower strong coupling of light and matter. Here we propose quantum plasmonic immunoassay sensing as an innovative scheme, which embeds immunoassay sensing with recently demonstrated room-temperature strong coupling in nanoplasmonic cavities. In our protocol, the antibody–antigen–antibody complex is chemically linked with a quantum emitter label. Placing the quantum-emitter-enhanced antibody–antigen–antibody complexes inside or close to a nanoplasmonic (hemisphere dimer) cavity facilitates strong coupling between the plasmon–polaritons and the emitter label resulting in signature Rabi splitting. Through rigorous statistical analysis of multiple analytes randomly distributed on the substrate in extensive realistic computational experiments, we demonstrate a drastic enhancement of the sensitivity up to nearly 1500% compared to conventional shifting-type plasmonic sensors. Most importantly and in stark contrast to classical sensing, we achieve in the strong-coupling (quantum) sensing regime an enhanced sensitivity that is no longer dependent on the concentration of antibody–antigen–antibody complexes down to the single-analyte limit. The quantum plasmonic immunoassay scheme thus not only leads to the development of plasmonic biosensing for single molecules but also opens up new pathways toward room-temperature quantum sensing enabled by biomolecular inspired protocols linked with quantum nanoplasmonics.

Journal article

Bello F, Sanvito S, Hess O, Donegan JFet al., 2019, Shaping and Storing Magnetic Data Using Pulsed Plasmonic Nanoheating and Spin-Transfer Torque, ACS PHOTONICS, Vol: 6, Pages: 1524-1532, ISSN: 2330-4022

Journal article

Bittner S, Guazzotti S, Zeng Y, Kim K, Wang QJ, Hess O, Cao Het al., 2019, Spatio-temporal dynamics of microlasers with chaotic ray dynamics

Broad-area semiconductor lasers used for high-power applications such as material processing and pump sources feature significant spatio-temporal instabilities [1]. Most attempts to stabilize them aim at reducing the number of transverse lasing modes via injection or feedback but fail at high powers. We demonstrate a different approach for stabilization via complex interference in asymmetric cavities with chaotic ray dynamics. This approach maintains multi-mode operation and is hence compatible with high-power operation [2].

Conference paper

Roman Castellanos L, Hess O, Lischner J, 2019, Single plasmon hot carrier generation in metallic nanoparticles, Communications Physics, Vol: 2, ISSN: 2399-3650

Hot carriers produced from the decay of localized surface plasmons in metallic nanoparticles are intensely studied because of their optoelectronic, photovoltaic and photocatalytic applications. From a classical perspective, plasmons are coherent oscillations of the electrons in the nanoparticle, but their quantized nature comes to the fore in the novel field of quantum plasmonics. In this work, we introduce a quantum-mechanical material-specific approach for describing the decay of single quantized plasmons into hot electrons and holes. We find that hot carrier generation rates differ significantly from semiclassical predictions. We also investigate the decay of excitations without plasmonic character and show that their hot carrier rates are comparable to those from the decay of plasmonic excitations for small nanoparticles. Our study provides a rigorous and general foundation for further development of plasmonic hot carrier studies in the plasmonic regime required for the design of ultrasmall devices.

Journal article

Tarasenko II, Page AF, Hamm JM, Hess Oet al., 2019, Nonlocal quantum gain facilitates loss compensation and plasmon amplification in graphene hyperbolic metamaterials, PHYSICAL REVIEW B, Vol: 99, ISSN: 2469-9950

Journal article

Dolan JA, Dehmel R, Demetriadou A, Gu Y, Wiesner U, Wilkinson TD, Gunkel I, Hess O, Baumberg JJ, Steiner U, Saba M, Wilts BDet al., 2019, Metasurfaces atop metamaterials: surface morphology induces linear dichroism in gyroid optical metamaterials, Advanced Materials, Vol: 31, ISSN: 0935-9648

Optical metamaterials offer the tantalizing possibility of creating extraordinary optical properties through the careful design and arrangement of subwavelength structural units. Gyroid-structured optical metamaterials possess a chiral, cubic, and triply periodic bulk morphology that exhibits a redshifted effective plasma frequency. They also exhibit a strong linear dichroism, the origin of which is not yet understood. Here, the interaction of light with gold gyroid optical metamaterials is studied and a strong correlation between the surface morphology and its linear dichroism is found. The termination of the gyroid surface breaks the cubic symmetry of the bulk lattice and gives rise to the observed wavelength- and polarization-dependent reflection. The results show that light couples into both localized and propagating plasmon modes associated with anisotropic surface protrusions and the gaps between such protrusions. The localized surface modes give rise to the anisotropic optical response, creating the linear dichroism. Simulated reflection spectra are highly sensitive to minute details of these surface terminations, down to the nanometer level, and can be understood with analogy to the optical properties of a 2D anisotropic metasurface atop a 3D isotropic metamaterial. This pronounced sensitivity to the subwavelength surface morphology has significant consequences for both the design and application of optical metamaterials.

Journal article

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