Strong coupling of exciton-polaritons in semiconductor microcavities

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Psychotic disorders are increasingly recognized as the extreme end of a progressive psychopathology continuum, with less advanced stages including the asymptomatic familial high-risk state (FHR), the help-seeking clinical high-risk state (CHR), and first episode psychosis (FEP). However, we lack data-driven analyses which capture the diversity of clinical, cognitive, functional, and neuroanatomical markers across all three early stages of psychosis, limiting our understanding of how the multimodal phenotype

Terahertz (THz) radiation occupies a spectral region between 100 GHz and 10 THz of growing interest for applications in spectroscopy, imaging, and high-speed communications. In free-space implementations, THz generation and detection are commonly achieved using nonlinear crystals through optical rectification and electro-optic sampling, photoconductive antennas based on III-V semiconductors, or more recently spintronic emitters. While these approaches provide large bandwidth and high fidelity, they typicall

Retrieving information through disordered scattering systems remains a major challenge in wireless communication and sensing due to the severe distortion and attenuation caused by multiple scattering. Here, we demonstrate robust focusing through random media using a leaky cavity made programmable by reconfigurable metasurfaces. We show that the leaky cavity leverages backscattering from the disordered medium to enhance the degree of control over the transmitted field. We achieve an enhancement in focused in

Extended efforts have been devoted to the study of strongly-interacting excitons and their dynamics, towards macroscopic quantum states of matter such as Bose-Einstein condensates of excitons and polaritons. Momentum-direct layer-hybridized excitons in transition metal dichalcogenides have attracted considerable attention due to their high oscillator strength and dipolar nature. However, the tunability of their interactions and dynamics remains unexplored. Here, we achieve an unprecedented control over the

Psychotic and mood disorders, including schizophrenia and bipolar disorder, are increasingly viewed as part of a psychosis spectrum disorder (PSD) continuum, sharing genetic and neurobiological features. This systematic review and meta-analysis examined fractional anisotropy (FA) and mean diffusivity (MD) using diffusion tensor imaging in PSD. Across 96 studies (N = 4,424 PSD, N = 5,004 controls for FA; N = 1,607 PSD, N = 1,709 controls for MD), FA reductions were consistently observed in the corpus callosu

people died by suicide, reflecting a 10% increase. In 2021 this number was 1561, and in 2022 1647 people completed suicide. While the number of violent suicide attempts increased by 16,5% between December 2019 and March in 2020, the estimated number of non-violent suicide attempts did not change in that period [1,2]. Given the forecasts of similar global emergency situations in the future, there is an imminent need to understand how such events impact suicidal behaviours to identify means of prevention and

Several animal and clinical studies have highlighted the ineffectiveness of fear extinction sessions delivered shortly after trauma exposure. This phenomenon, termed the immediate extinction deficit, refers to situations in which extinction programs applied shortly after fear conditioning may result in the reduction of fear behaviors (in rodents frequently measured as freezing responses to the conditioned cue/s) during extinction training, but failure to consolidate this reduction in the long-term. The mole

III-nitride based microcavities (MCs) appear as one of the most promising candidates for the realization of room temperature (RT) polariton laser diodes. The present work focuses on the properties of low In content InGaN/GaN multiple quantum wells (MQWs) in terms of inhomogeneous broadening, exciton localization energy, and plastic strain relaxation. For a small number of such QWs, an inhomogeneous line broadening of 41 meV is reported, which is compatible with strong coupling regime requirements. By contra

We have demonstrated theoretically that it is possible to use the resonant coupling of exciton-polaritons in a planar microcavity and Tamm plasmons at a metal film on the surface of the structure to provide lateral spatial control of the exciton-polaritons within the cavity. The resonant coupling of the Tamm plasmons to cavity exciton-polaritons results in a triplet of hybrid plasmon-exciton-polariton modes with the lowest at a significantly lower energy than that of the unperturbed exciton-polaritons. Furt

In visual backward masking, a target is followed by a blank screen (ISI) and, then, a mask which deteriorates target processing. Schizophrenic patients show strong but complex processing deficits in visual masking compared to healthy controls. There is evidence for a shared genetic etiology in bipolar disorders and schizophrenia prompting the question whether both groups of patients show also analogous information processing deficits. Here, we examined whether the complex masking effects we found previously

We present a novel theory of polaritons which contains the crucial tools to securely tackle the many-body physics of polaritons. Microcavitly polaritons are central to exciting Bose-Einstein condensation and parametric scattering experiments in semiconductors. Besides Coulomb and Pauli scattering (dressed by the relevant exciton-Hopfield coefficients), it beautifully unravels a novel fundamental scattering between two polaritons which can be physically associated with a photon-assisted exchange process, wit

Photoluminescence of p-type modulation doped (Cd,Mn)Te quantum wells is studied with carrier density up to 5 X 10(11) cm(-2) at various spin splittings. This splitting can be made larger than the characteristic energies of the system thanks to the giant Zeeman effect. At small spin splitting and regardless of the carrier density, the photoluminescence exhibits a single line, which corresponds to the charged exciton in the singlet state. Above a certain spin splitting, the charged exciton is destabilized in

Microcavity exciton polaritons, the fundamental optical excitations of semiconductor microcavities with quantum wells inside, have been proposed as promising candidates for observing stimulated scattering, condensation and other phenomena related to the bosonic nature of excitons. Having a light mass, quantum degeneracy of polaritons can be reached at low densities and high temperatures. But the radiative time of polaritons is very short (in the picosecond range) and usually prevents an efficient thermaliza

A neutron-scattering study of nonsuperconducting La2-xSrxCaCu2O6 (x=0 and 0.2), a bilayer copper oxide without CuO chains, has revealed an unexpected tetragonal-to-orthorhombic transition with a doping dependent transition temperature. The predominant structural modification below the transition is an in-plane shift of the apical oxygen. In the doped sample, the orthorhombic superstructure is strongly disordered, and a glassy state involving both magnetic and structural degrees of freedom develops at low te

Near-field optical spectroscopy is used to investigate the effects of disorder in the optical processes in semiconductor quantum wires. We observe photoluminescence emissions from extended, delocalized excitons at low temperatures (5 K) and low excitation densities. Combining high spectral and spatial resolution, we isolate homogeneous emission lines from excitons delocalized over distances up to 600 nm in the fundamental state. The energies of the emissions are consistent with different quantum spatial con

Pump-probe measurements in a microcavity containing a quantum well show that a population of circularly polarized (sigma(+)) excitons can completely inhibit the transition to sigma(-) one-exciton states by transferring the oscillator strength to the biexcitonic resonance. With increasing pump intensity the linear exciton-polariton doublet evolves into a triplet polariton structure and finally into a shifted biexciton-polariton doublet. A theoretical model of interacting excitons demonstrates that the crosso

We present a comparative study of time-integrated four-wave-mixing and femtosecond emission under resonant excitation on excitons in weakly disordered GaAs quantum wells. At highest exciton densities when dephasing dominates the spectral width (homogeneous broadening), we find that the rise time of the incoherent luminescence signal is given by T-2/2. At lowest densities, optical coherence times approach the exciton radiative lifetime (15 to 20 ps). This confirms our previous result that coherent resonant R

Chemical beam epitaxy (CBE) grown InAsP/InGaAsP edge-emitting laser diodes on GaAs substrates obtained by localised fusion in a nitrogen environment exhibit high quality fused interfaces. A degradation of fused lasers is observed which is attributed to the disordering of quantum wells at fusion temperatures induced by point defects incorporated during low temperature growth.

A theoretical investigation of the dynamics in a photoluminescence experiment in strong-coupling semiconductor microcavities is presented. Radiative recombination rates of microcavity polaritons in the strong-coupling regime and their scattering rates with acoustic phonons are used to study the polariton dynamics in a photoluminescence experiment, as a function of the temperature and the cavity detuning. It is found that the leaky modes of the distributed Bragg reflectors enclosing the cavity constitute the

We develop a quantum mechanical model for the interaction of excitons in a microcavity embedded quantum well with a short resonant laser pulse. The model assumes full in-plane coherence. A Gaussian distribution of exciton slates is included in order to take into account the exciton inhomogeneous broadening. A coupling with a classical electromagnetic held provides the initial excitation pulse, and the time dependent emitted signal is calculated. Very good agreement with the recent results of time-resolved l

Strong coupling of exciton-polaritons in semiconductor microcavities

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Data-driven profiles of psychosis stages reveal distinct and overlapping clinical, cognitive, and neuroanatomical phenotypes

Hybrid silicon-organic integrated photonic circuits for broadband terahertz field-resolved detection

Backscatter communication through disordered media enabled by a programmable leaky cavity

Electrically tunable ultrafast dynamics and interactions of hybrid excitons in a 2D semiconductor bilayer

Transdiagnostic impairments in white matter integrity across the Psychosis Continuum: a systematic review and meta-analysis of diffusion studies

Vulnerability markers in offspring of bipolar disorder patients: links between symptoms and functional and structural neural connectivity

Involvement of CRFR1 in the basolateral amygdala in the immediate fear extinction deficit

Investigation of InGaN/GaN quantum wells for polariton laser diodes

Hybrid states of Tamm plasmons and exciton-polaritons

Schizophrenic and bipolar patients reveal identical backward masking deficits

Novel exact approach to polariton-polariton interactions and scattering rates: the limits of bosonization

Photoluminescence of p-doped quantum wells with strong spin splitting

Polariton amplification in semiconductor microcavities

Structural and magnetic instabilities of La2-xSrxCaCu2O6

Near-field imaging of one-dimensional excitons delocalized over mesoscopic distances

Crossover from exciton to biexciton polaritons in semiconductor microcavities

Relevance of dephasing processes for the ultrafast rise of emission from resonantly created excitons in quantum wells

Characteristics of InAsP/InGaAsP Edge Emitting Laser Diodes Obtained by Localised Fusion on GaAs Substrates

Photoluminescence decay times in strong-coupling semiconductor microcavities

Theory of time-resolved light emission from polaritons in a semiconductor microcavity under resonant excitation