arXiv subjects

Wenna Du

Publications and source records attributed to Wenna Du.

8 recordsLinked to original sources

arXiv2026

Reconfigurable ultrafast perovskite polariton logic gates via nonlinear dynamics

Exciton-polaritons provide a great platform for developing ultrafast all-optical logic gates for quantum and optical chips. However, progress toward practical polariton logic remains limited due to incomplete logical functionality on a single device. Herein, we present a single-device perovskite polariton platform enabling reconfigurable, ultrafast logic gates with functional completeness. The device consists of an optically trapped perovskite microwire, generating well-controlled non-equilibrium polariton condensation states for multiple logic operation channels. By tailoring the power of signal and gate beams, the same device is programmed to execute three basic Boolean functions (AND,OR,and NOT) and a high-order XOR function with a high on/off ratio of 21 dB, and a fast response time 6.7 ps. The reconfigurability arises from the selective activation of different nonlinear responses of polariton condensates, including amplification, seeding state transitions, and nonlinear interaction. These results provide valuable insights for advancing exciton-polariton logic gates.

physics.optics↗

arXiv2025

Ultrafast Exciton-Polariton Transport and Relaxation in Halide Perovskite

Halide perovskites offer a great platform for room-temperature exciton-polaritons (EPs) due to their strong oscillator strength and large exciton binding energy, promising applications in next-generation photonic and polaritonic devices. Efficient manipulation of EP transport and relaxation is critical for device performance, yet their spatiotemporal dynamics across different in-plane momenta (k//) remain poorly understood due to limitations in experimental access. In this work, we employ energy-resolved transient reflectance microscopy (TRM) combined with the dispersion relation of EPs to achieve high-resolution imaging of EP transport at specific k//. This approach directly reveals the quasi-ballistic transport and ultrafast relaxation of EPs in different k// regions, showcasing diffusion as fast as ~490 cm2/s and a relaxation time of ~95.1 fs. Furthermore, by tuning the detuning parameter, we manipulate the ballistic transport group velocity and relaxation time of EPs across varying k//. Our results reveal key insights into the dynamics of EP transport and relaxation, providing valuable guidance for the design and optimization of polaritonic devices.

cond-mat.mtrl-sci↗

arXiv2025

All-optical and ultrafast control of high-order exciton-polariton orbital modes

Exciton-polaritons flows within closed quantum circuits can spontaneously form phase-locked modes that carry orbital angular momentum (OAM). With its infinite set of angular momentum quantum numbers, high-order OAM represents a transformative solution to the bandwidth bottleneck in multiplexed optical communication. However, its practical application is hindered by the limited choice of materials which in general requires cryogenic temperatures and the reliance on mechanical switching. In this work, we achieve stable and high-order (up to order of 33) OAM modes by constructing a closed quantum circuit using the halide perovskite microcavities at room temperature. By controlling the spatial and temporal symmetry of the closed quantum circuits using another laser pulse, we achieve significant tuning OAM of EP flows from 8 to 12. Our work demonstrate all-optical and ultrafast control of high-order OAM using exciton-polariton condensates in perovskite microcavities that would have important applications in high-throughput optical communications.

physics.optics↗

arXiv2023

Room-Temperature Bound States in the Continuum Polariton Condensation

Exciton-polaritons resulting from the strong exciton-photon interaction stimulate the development of novel coherent light sources with low threshold, long range spatial, and temporal coherence to circumvent the ever increasing energy demands of optical communications. Polaritons from bound states in the continuum (BICs) are promising for Bose-Einstein condensation owing to their infinite quality factors that enlarge photon lifetimes and benefit polariton accumulations. However, BIC polariton condensation remains limited to cryogenic temperatures ascribed to the small exciton binding energies of conventional material platforms. Herein, we demonstrated a room-temperature BIC polaritonic platform based on halide perovskite air-hole photonic crystals, profiting from the non-radiative BIC states and stable excitons of cesium lead bromide. BIC polariton condensation was achieved near the dispersion minimum that generates directional vortex beam emission with long-range coherence. Our work provides a significant basis for the applications of polariton condensates for integrated photonic and topological circuits.

cond-mat.mes-hall↗

arXiv2020

Zone-folded longnitude acoustic phonons driving self-trapped state emission in colloidal CdSe nanoplate superlattice

Colloidal cadmium chalcogenide nanoplates are two-dimensional semiconductors that have shown great application prospect for light-emitting technologies. Self-trapped state (STS), a special localized state originated from strong electron-phonon coupling (EPC), has great potential in one-step white light luminance owing to its broadband emission linewidth. However, achieving STS in cadmium chalcogenide nanocrystals is extremely challenging due to their intrinic weak EPC nature. By building hybrid superlattice (SL) structures via self-assembly of colloidal CdSe nanoplates (NPLs), we demonstrated an emergence of zone-folded longnitude acoustic phonons (ZFLAP) differ from monodispersed NPLs, and observed a broadband STS emission in spectra range of 450-600 nm. Through femtosecond transient absorption and impulsive vibrational spectroscopy, we revealed that STS is generated in time scale of ~500 fs and is driven by strong coupling of excitons and ZFLAPs with Huang-Rhys parameter as large as ~22.7. Our findings provide a new avenue for generating and manipulating STS emission by artificially designing and building hybrid periodic structures superior to single material optimization.

cond-mat.mtrl-sci↗

arXiv2018

Room Temperature Continuous-wave Excited Biexciton Emission in CsPbBr3 Nanocrystals

Biexcitons are a manifestation of many-body excitonic interactions crucial for quantum information and quantum computation in the construction of coherent combinations of quantum states. However, due to their small binding energy and low transition efficiency, most biexcitons in conventional semiconductors exist either at cryogenic temperature or under femtosecond pulse laser excitation. Here we demonstrate room temperature, continuous wave driven biexciton states in CsPbBr3 perovskite nanocrystals through coupling with a plasmonic nanogap. The room temperature CsPbBr3 biexciton excitation fluence (~100 mW/cm2) is reduced by ~10^13 times in the Ag nanowire-film nanogaps. The giant enhancement of biexciton emission is driven by coherent biexciton-plasmon Fano interference. These results provide new pathways to develop high efficiency non-blinking single photon sources, entangled light sources and lasers based on biexciton states.

cond-mat.mes-hall↗

arXiv2017

Strong Exciton-Photon Coupling and lasing behavior in All-Inorganic CsPbBr3 Micro/nanowire Fabry-Perot cavity

Macroscopic spontaneous coherence of exciton-polariton in semiconductor cavity is one important research field in condensed matter physics. All-inorganic micro/nanowire Fabry-Pérot cavity with excellent optical performance makes it possible to realize strong coupling and lasing of exciton-photon at room temperature. In this work, we demonstrated strong coupling of exciton-photon and polariton lasing in CsPbBr3 micro/nanowires synthesized by CVD method. By exploring spatial resolved PL spectra of CsPbBr3 cavity, we observed mode volume dependent coupling strength , as well as significant increase in group index. Moreover, low threshold polariton lasing was achieved at room temperature within strong coupling regime; the polariton characteristic is confirmed by comparing lasing spectra with waveguided output spectra and the dramatically reduced lasing threshold. Our present results provide new avenues to achieve high coupling strengths potentially enabling application of exciting phenomena such as Bose-Einstein condensation of polaritons, efficient light-emitting diodes and lasers.

cond-mat.mes-hall↗

arXiv2017

Exciton-Polaritons in Hybrid Inorganic-organic Perovskite Fabry-Pérot Microcavity

Exciton-polaritons in semiconductor microcavities generate fascinating effects such as long-range spatial coherence and Bose-Einstein Condensation (BEC), which are attractive for their potential use in low threshold lasers, vortices and slowing light, etc. However, currently most of exciton-polariton effects either occur at cryogenic temperature or rely on expensive cavity fabrication procedures. Further exploring new semiconductor microcavities with stronger exciton photon interaction strength is extensively needed. Herein, we demonstrate room temperature photon exciton strong coupling in hybrid inorganic-organic CH3NH3PbBr3 Fabry-Pérot microcavities for the first time. The vacuum Rabi splitting energy is up to ~390 meV, which is ascribed to large oscillator strength and photon confinement in reduced dimension of optical microcavities. With increasing pumping energy, exciton-photon coupling strength is weakened due to carrier screening effect, leading to occurrence of photonic lasing instead of polartion lasing. The demonstrated strong coupling between photons and excitons in perovskite microcavities would be helpful for development of high performance polariton-based incoherent and coherent light sources, nonlinear optics, and slow light applications.

cond-mat.mes-hall↗