A5044148579- Terahertz technology and applications
- Quantum and electron transport phenomena
- Photonic and Optical Devices
- Spectroscopy and Laser Applications
- Semiconductor Quantum Structures and Devices
- Advanced Fiber Laser Technologies
- Quantum optics and atomic interactions
- Superconducting and THz Device Technology
- Magnetic properties of thin films
- Topological Materials and Phenomena
- Gyrotron and Vacuum Electronics Research
- Graphene research and applications
- Mechanical and Optical Resonators
- Semiconductor Lasers and Optical Devices
- Plasmonic and Surface Plasmon Research
- Strong Light-Matter Interactions
- 2D Materials and Applications
- Molecular Junctions and Nanostructures
- Atomic and Subatomic Physics Research
- Atmospheric Ozone and Climate
- Laser Design and Applications
- Physics of Superconductivity and Magnetism
- Thermal Radiation and Cooling Technologies
- Photonic Crystals and Applications
- Quantum Information and Cryptography
Université Paris Cité
2015-2024
École Normale Supérieure - PSL
2015-2024
Université Paris Sciences et Lettres
2015-2024
Centre National de la Recherche Scientifique
2015-2024
Sorbonne Université
2015-2024
Laboratoire de Physique de l'ENS
2019-2024
Sorbonne Paris Cité
2015-2024
Université Paris 1 Panthéon-Sorbonne
2022-2023
Max Planck Institute for Chemical Physics of Solids
2022
Délégation Paris 7
2014-2021
Van der Waals heterostructures have promised the realisation of artificial materials with multiple physical phenomena such as giant optical nonlinearities, spin-to-charge interconversion in spintronics and topological carrier protection, a single layered device through an infinitely diverse set quantum materials. However, most efforts only focused on exfoliated material that inherently limits both dimensions scalability for applications. Here, we show epitaxial growth large area insulators...
Nonlinear couplings between photons and electrons in new materials give rise to a wealth of interesting nonlinear phenomena. This includes frequency mixing, optical rectification or current generation, which are particular interest for generating radiation spectral regions that difficult access, such as the terahertz gap. Owing its specific linear dispersion high electron mobility at room temperature, graphene is particularly attractive realizing strong effects. However, since...
Dispersion compensation is vital for the generation of ultrashort and single cycle pulses from modelocked lasers across electromagnetic spectrum. It typically based on addition an extra dispersive element to laser cavity that introduces a chromatic dispersion opposite gain medium. To date, however, no schemes have been successfully applied terahertz (THz) quantum cascade short stable pulse in THz range. In this work, monolithic on‐chip scheme realized QCL, permitting be considerably...
We demonstrate broadband (20 THz), high electric field, terahertz generation using large area interdigitated antennas fabricated on semi-insulating GaAs. The bandwidth is characterized as a function of incident pulse duration (15-35 fs) and pump energy (2-30 nJ). Broadband spectroscopy PTFE shown. Numerical Drude-Lorentz simulations the generated THz pulses are performed excitation duration, showing good agreement with experimental data.
Spintronic structures are extensively investigated for their spin–orbit torque properties, required magnetic commutation functionalities. Current progress in these materials is dependent on the interface engineering optimization of spin transmission. Here, we advance analysis ultrafast spin-charge conversion phenomena at ferromagnetic-transition metal interfaces due to inverse spin-Hall effect properties. In particular, intrinsic Pt-based systems and extrinsic Au:W Au:Ta NiFe/Au:(W,Ta)...
Abstract The use of fundamental modelocking to generate short terahertz (THz) pulses and THz frequency combs from semiconductor lasers has become a routine affair, using quantum cascade (QCLs) as gain medium. However, unlike classic laser diodes, no demonstrations harmonic modelocking, active or passive, have been shown in QCLs, where multiple per round trip are generated when the is modulated at harmonics cavity’s round-trip frequency. Here, time-resolved techniques, we show for first time...
The generation of ultrashort pulses from quantum cascade lasers (QCLs) has proved to be challenging.It been suggested that the ultrafast electron dynamics these devices is limiting factor for modelocking and hence pulse formation.Even so, clear terahertz (THz) QCLs recently demonstrated but exact mechanism not fully understood.Here we demonstrate dominant necessary active in fact synchronization between propagating electronic modulation generated THz QCL.By using phase resolved detection...
Abstract Graphene/hBN heterostructures are promising active materials for devices in the THz domain, such as emitters and photodetectors based on interband transitions. Their performance requires long carrier lifetimes. However, recombination processes graphene possess sub-picosecond characteristic times large non-equilibrium densities at high energy. An additional channel has been recently demonstrated graphene/hBN by emission of hBN hyperbolic phonon polaritons (HPhP) with picosecond decay...
Abstract Millimeter wave (mmWave) generation using photonic techniques has so far been limited to the use of near-infrared lasers that are down-converted mmWave region. However, such methodologies do not currently benefit from a monolithic architecture and suffer quantum defect i.e. difference in photon energies between region, which can ultimately limit conversion efficiency. Miniaturized terahertz (THz) cascade (QCLs) have inherent advantages this respect: their low energy photons,...
Abstract Platinum diselenide () is a promising two‐dimensional (2D) material for the terahertz (THz) range as, unlike other transition metal dichalcogenides (TMDs), its bandgap can be uniquely tuned from semiconductor in near‐infrared to semimetal with number of atomic layers. This gives unique THz photonic properties that layer‐engineered. Here, we demonstrate controlled nonlinearity—tuned monolayer bulk —can realized wafer size polycrystalline through generation ultrafast photocurrents and...
Abstract Terahertz (THz) spin‐to‐charge conversion has become an increasingly important process for THz pulse generation and as a tool to probe ultrafast spin interactions at magnetic interfaces. However, its relation traditional, steady state, ferromagnetic resonance techniques is poorly understood. Here, nanometric trilayers of Co/X/Pt (X = Ti, Au or Au:W alloy) are investigated function the “X” layer thickness, where emission generated by inverse Hall effect compared Gilbert damping...
Spin-to-charge conversion (SCC) involving topological surface states (TSS) is one of the most promising routes for highly efficient spintronic devices terahertz (THz) emission. Here, THz generation generally occurs mainly via SCC consisting in dynamical spin injection into spin-locked TSS. In this work, we demonstrate sizable emission from a nanometric thick insultator (TI)/ferromagnetic junction - SnBi$_2$Te$_4$/Co specifically designed to avoid bulk band crossing with TSS at Fermi level,...
We demonstrate a table-top source delivering ultra-broadband THz pulses with electric field strength exceeding 100 kV/cm at repetition rate of 200 kHz. The is based on optical rectification 23 fs 1030 nm delivered by ytterbium-doped fiber laser followed nonlinear temporal compression stage. generate conversion efficiency up to 0.11 % spectrum extending 11 using 1 mm thick GaP crystal and 0.016 30 µm GaSe crystal. essential features the emitted pulse spectra are well captured simulations...
The helicity of three-dimensional (3D) topological insulator surface states has drawn significant attention in spintronics owing to spin-momentum locking where the carriers' spin is oriented perpendicular their momentum. This property can provide an efficient method convert charge currents into currents, and vice-versa, through Rashba-Edelstein effect. However, experimental signatures these spin-charge conversion are extremely difficult disentangle from bulk state contributions. Here, spin-...
Spintronic terahertz (THz) emitters based on the inverse spin Hall effect in ferromagnetic/heavy metal (FM/HM) heterostructures have become important sources for THz pulse generation. The design, materials, and control of these interfaces at nanometer level vital to engineer their emission properties. In this work, we present studies optimization such structures through a multi-pronged approach, taking advantage material interface engineering enhance spintronic emission. This includes...
2D materials, such as transition metal dichalcogenides, are ideal platforms for spin-to-charge conversion (SCC) they possess strong spin-orbit coupling (SOC), reduced dimensionality and crystal symmetries well tuneable band structure, compared to metallic structures. Moreover, SCC can be tuned with the number of layers, electric field, or strain. Here, in epitaxially grown PtSe2 by THz spintronic emission is studied since its 1T symmetry SOC favor SCC. High quality as-grown layers...
Spintronic terahertz emitters (STEs), based on optical excitation of nanometer thick ferromagnetic/heavy metal (FM/HM) heterojunctions, have become important sources for the generation (THz) pulses. However, efficiency optical-to-THz conversion remains limited. Although techniques been developed to enhance absorption, no investigations studied application THz cavities. Here, STEs in a selected spectral range, FM/HM structures are realized ultra-thin sapphire layers with metallic mirrors create
The spectral gain of bound-to-continuum terahertz quantum cascade lasers (QCLs) is measured as a function current density using time-domain spectroscopy. During lasing action the full width at half maximum (FWHM) found to monotonically decrease with increasing until stops which point FWHM reaches minimum (0.22 THz for laser operating 2.1 THz). Band structure calculations show that narrowing due alignment and misalignment injector active region applied bias field.
We investigate the nonlinear refraction induced by Rydberg excitons in Cu_{2}O. Using a high-precision interferometry imaging technique that spatially resolves phase shift, we observe significant shifts at extremely low laser intensity near each exciton resonance. From this, derive index n_{2}, present n_{2} spectrum for principal quantum numbers n≥5, and report large values of order 10^{-3} mm^{2}/mW. Moreover, rapid saturation Kerr nonlinearity find I_{sat} decreases as n^{-7}. explain...
The authors study the interaction of complementary terahertz (THz) split ring resonators with THz surface plasmon polaritons (SPPs) as a function meta‐atom distance. transmission properties 15 samples for which array dimensions are varied keeping resonator shape constant investigated. linewidth inductive‐capacitive (LC‐)resonance is decreasing increasing distance, up to frequency matching first SPP‐mode. SPP‐mode couples narrow LC‐resonance leading an anti‐crossing modes. In contrast, tunes...
Abstract Diffraction is the ultimate limit at which details of objects can be resolved in conventional optical spectroscopy and imaging systems. In THz spectral range, systems increasingly rely on ultra-broadband radiation (extending over more 5 octaves) making a great challenge to reach resolution limited by diffraction. Here, we propose an original easy-to-implement wavefront manipulation concept achieve ultrabroadband system with diffraction-limited resolution. Applying this large-area...
Electromagnetic resonators, which are based on optical cavities or electronic circuits, key elements to enhance and control light-matter interaction. In the THz range, current exhibit very high-quality factors with $(\lambda/2)^3$ mode volumes limited by diffraction, whereas resonant circuits show low quality factor but provide strong subwavelength effective volume ($10^{-6} \lambda^3$). To overcome limitations of each type resonator, great efforts being devoted improving performances...
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We present a comprehensive investigation of optical parametric oscillation in resonantly excited one-dimensional semiconductor microcavities with embedded quantum wells. Such solid-state structures feature fine control over light-matter coupling and produce photonic/polaritonic mode fan that is exploited for the efficient emission beams. implement an energy-degenerate oscillator balanced signal idler intensities via polarization-inverting mechanism. In this paper, we (i) precisely review...