We report an extended family of spin textures zero-dimensional exciton-polaritons spatially confined in tunable open microcavity structures. The transverse-electric--transverse-magnetic (TE-TM) splitting, which is enhanced the cavity structures, leads to polariton eigenstates carrying quantized vortices. Depending on strength and anisotropy confining potential TE-TM induced can be tuned via excitonic or photonic fractions, exciton-polariton emissions exhibit either spin-vortex-like patterns...

We report on the spin properties of bright polariton solitons supported by an external pump to compensate losses. observe robust circularly polarized when a is applied, result attributed phase synchronization between nondegenerate TE and TM modes at high momenta. For case linearly pump, either σ+ or σ- can be switched in controlled way writing beam, respectively. This feature arises directly from widely differing interaction strengths co- cross-circularly polaritons. In orthogonally beams,...

We present a method to implement 3-dimensional polariton confinement with in-situ spectral tuning of the cavity mode. Our tunable microcavity is hybrid system consisting bottom semiconductor distributed Bragg reflector (DBR) containing quantum wells (QWs) grown on top and dielectric concave DBR separated by micrometer sized gap. Nanopositioners allow independent positioning two mirrors mode energy can be tuned controlling distance between them. When close resonance, we observe characteristic...

Polariton condensates are investigated in periodical potentials created by surface acoustic waves (SAWs) using both coherent and incoherent optical excitation. Under resonant pumping, formed due to polariton-parametric scattering from the pump. In this case, excitation spectrum of condensate shows a strong reduction energy gap arising modulation, indicating efficient screening SAW potential spatial modulation polariton density. The observed results good agreement with model based on...

We study, at low temperature and zero magnetic field, the hole-spin dynamics in InAs/GaAs quantum dots. measure relaxation time a scale longer than dephasing (about ten nanoseconds), imposed by hole-nuclear hyperfine coupling. use pump-probe configuration compare two experimental techniques based on differential absorption. The first one works domain, second is new method, dark-bright time-scanning spectroscopy (DTS), working frequency domain. measured times, using these techniques, are very...

We report propagating bound microcavity polariton soliton arrays consisting of multipeak structures either along ($x$) or perpendicular ($y$) to the direction propagation. Soliton up five solitons are observed, with number controlled by size and power triggering laser pulse. The breakup $x$ occurs when effective area trigger pulse exceeds characteristic determined polariton-polariton interactions. Narrowing emission in energy-momentum space indicates phase locking between adjacent solitons,...

We study the hole-spin relaxation in p-doped InAs quantum dots. Two mechanisms are evidenced, at low magnetic field ($0\ensuremath{\le}B\ensuremath{\le}2T$) and temperature ($2\ensuremath{\le}T\ensuremath{\le}50K$), by using a pump-probe configuration recent experimental technique working frequency domain. At $T=2K$, coupling to nuclear spins hole wave-function inhomogeneity fix rate value,...

The spin dynamics of a resident carrier, hole or electron, in singly charged InAs/GaAs quantum dots has been measured by pump-probe experiments. relative strength the to electron hyperfine couplings with nuclei is obtained studying magnetic-field dependence resident-carrier polarization. We find, good agreement recent theoretical studies, that coupling ten times smaller than one.

We have performed pump-probe experiments in $p$-doped InAs/GaAs quantum dots leading to the all-optical initialization and readout of hole spins. In order describe these experiments, we modelized interconnected dynamics photoelectron spin resident spin, triggered through optical excitation by a train short pulses. A complete description this is obtained including hyperfine coupling as common decoherence mechanism for electron Periodic conditions arbitrary values pump power external magnetic...

In this study, we evidence hole spin mode locking in a largely inhomogeneous $p$-doped InAs quantum dot (QD) ensemble, $\ensuremath{\Delta}{g}_{x}^{h}/{g}_{x}^{h}\ensuremath{\approx}34%$, which allows us to reveal long coherence time of ${T}_{2}^{h}\ensuremath{\approx}0.8\phantom{\rule{0.28em}{0ex}}\ensuremath{\mu}\mathrm{s}$. addition, with two-pump experiment, demonstrate, low magnetic range 60--120 mT, the possibility synchronize and tune single subset QDs through distribution....

Quantum emitters in two-dimensional layered hexagonal boron nitride are quickly emerging as a highly promising platform for next-generation quantum technologies. However, the precise identification and control of defects key parameters to achieve next step their development. We conducted comprehensive study by analyzing over 10,000 photoluminescence emission lines from liquid exfoliated hBN nanoflake samples, revealing 11 narrow sets defect families within 1.6 2.2 eV energy range. This...

The exact optical response of quantum few-level systems depends crucially on the choice incoming pulse areas. We use four-wave mixing (FWM) spectroscopy to infer coherent and dynamics single InAs dots (QDs) study their area dependence. By combining atomic force microscopy with FWM hyperspectral imaging, we show that retrieved signals originate from individual QDs enclosed in natural photonic defects. optimized light-matter coupling these defects allows us perform our studies a wide range...

We have obtained the optical pumping of hole spins, in p-doped InAs/GaAs quantum dots, via generation an intermediate trion state by a train circularly polarized pulses. show that we can optically control orientation initialized spin, independently state, choosing excitation energy light. This brings supplementary degree freedom for hole-spin manipulations dots.

The initialization of a resident hole spin by the absorption circularly polarized light at resonance involves formation an excited state called trion state. For pure heavy hole, this optical is mediated hyperfine electron-nuclear coupling in We show here that for mixed-hole additional mechanism appears, associated to 'crossed transitions'; it becomes dominant and keeps high level polarization when magnetic field screens interaction. Finally, using simple model, we obtain good theoretical...

Group-VII transition metal dichalcogenides like ReS₂ holds novel in-plane anisotropic excitons, owing to their reduced lattice symmetry. Despite potential, the coherent dynamics of these excitons remain unexplored yet. To address properties, here, we perform polarization sensitive, ultrafast non-linear optical measurements on ReS₂. By implementing four-wave mixing spectroscopy along with spectral heterodyning detection at microscopic limit, measure coherence and...

Quantum emitters in two-dimensional layered hexagonal boron nitride are quickly emerging as a highly promising platform for next-generation quantum technologies. However, precise identification and control of defects key parameters to achieve the next step their development. We conducted comprehensive study by analyzing over 10,000 photoluminescence emission lines, revealing 11 distinct defect families within 1.6 2.2 eV energy range, challenging hypotheses random distribution. These findings...

The discovery of in-plane anisotropic excitons in two-dimensional layered semiconductors enables state-of-the-art nanophotonic applications. A fundamental yet unknown parameter these quasiparticles is the coherence time (T_2 ), which governs quantum dephasing timescale, over coherent superposition can be maintained and manipulated. Here, we report direct measurement T_2 within sub-picosecond range, along with multiple population decay timescales (T_1 ) at resonance for pristine rhenium...

We model pump-probe experiments leading to the all-optical initialization of hole spin a p-doped InAs/GaAs quantum dots ensemble. consider selection rules mixed states and include periodic excitation conditions. Hyperfine interaction is taken into account as common decoherence mechanism for spins electrons holes. show that degree polarization can be maximized by quenching action hyperfine with small applied magnetic field. However additional relaxation mechanisms, in microsecond time range,...

A review of the physics and experimental investigations bright polariton solitons in semiconductor microcavities is given. Key properties solitons, how they are affected by soliton-soliton interactions soliton trains, discussed.

We report on element-specific measurements of ultrafast demagnetization and magnetization precession damping in permalloy thin films. Magnetization dynamics induced by an optical pump at 1.5 eV is probed simultaneously the ${M}_{2,3}$ edges Ni Fe with high-order harmonics for moderate rates (less than 50%). The role intersublattice exchange interaction both longitudinal transverse analyzed a Landau-Lifshitz-Bloch description ferromagnetically coupled sublattices. It shown that governs...

Quantum emitters in two-dimensional layered hexagonal boron nitride are quickly emerging as a highly promising platform for next-generation quantum technologies. However, precise identification and control of defects key parameters to achieve the next step their development. We conducted comprehensive study by analyzing over 10,000 photoluminescence emission lines, revealing 11 distinct defect families within 1.6 2.2 eV energy range. This challenges hypotheses random distribution. also...