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Interference between the electric and magnetic dipole-induced in Mie nanostructures has been widely demonstrated to tailor the scattering field, which was commonly used in optical nano-antennas, filters, and routers. The dynamic control of scattering fields based on dielectric nanostructures is interesting for fundamental research and important for practical applications. Here, it is shown theoretically that the amplitude of the electric and magnetic dipoles induced in a vanadium dioxide nanosphere can be manipulated by using laser-induced metal-insulator transitions, and it is experimentally demonstrated that the directional scattering can be controlled by simply varying the irradiances of the excitation laser. As a straightforward application, we demonstrate a high-performance optical modulator in the visible band with high modulation depth, fast modulation speed, and high reproducibility arising from a backscattering setup with the quasi-first Kerker condition. Our method indicates the potential applications in developing nanoscale optical antennas and optical modulation devices.

Two-dimensional (2D) transition metal dichalcogenide (TMDC) monolayers are promising materials for light-emitting devices due to their excellent electric and optical properties. However, defects are inevitably introduced in the fabrication of TMDC monolayers, significantly influencing their emission properties. Although photoluminescence (PL) is considered as an effective tool for investigating the defects in TMDC monolayers. However, the PL from the defect-bound excitons is revealed only at low temperatures. Here, we show that the PL from the defect-bound excitons in a WS2 monolayer can be effectively revealed at room temperature by exploiting the transverse electric polarized wave supported by a Si3N4/Ag heterostructure. It is revealed that the defect-bound excitons in all possible positions of the WS2 monolayer can be effectively excited by the TE wave with significantly enhanced in-plane electric field localized on the surface of the Si3N4 layer. In addition, the emission from defect-bound excitons can propagate to the collection point with small attenuation. More importantly, the exciton dynamics in the WS2 monolayer can be modified by the Si3N4/Ag heterostructure, allowing the simultaneous excitation of neutral excitons, charge excitons (trions), and defect-bound excitons in the WS2 monolayer attached on the Si3N4/Ag heterostructure. We inspect the PL spectra obtained at different positions and find that the relative intensity of defect-bound excitons depends on the collection position. We also examine the dependences of the PL intensity and bandwidth on the excitation power for the three types of excitons. It is found that they exhibit different behaviors from those observed in the optical measurements by using the traditional excitation method. Our findings suggest a new way for exciting and studying the dynamics of multi-excitons at room temperature and indicate the potential applications of the TE wave in probing the defects in TMDC monolayers.

Halide perovskite materials have garnered significant research attention due to their remarkable performance in both photoharvesting photovoltaics and photoemission applications. Recently, self-assembled CsPbBr3 superstructures (SSs) have been demonstrated to be promising lasing materials. In this study, we report the ultrastable two-photon-pumped amplified stimulated emission from a CsPbBr3 SS/Ag hybrid microcavity with a low threshold of 0.8 mJ/cm2 at room temperature. The experimental results combined with numerical simulations show that the CsPbBr3 SS exhibits a significant enhancement in the electromagnetic properties in the hybrid microcavity on Ag film, leading to the uniform spatial temperature distribution under the irradiation of a pulsed laser, which is conducive to facilitate the recrystallization process of the QDs and improve their structural integrity and optical properties. This study provides a new idea for the application of CsPbBr3/Ag hybrid microcavity in photonic devices, demonstrating its potential in efficient optical amplification and upconversion lasers. [ABSTRACT FROM AUTHOR]

We investigate numerically and experimentally the optical properties of the transverse electric (TE) waves supported by a dielectric-metal heterostructure. They are considered as the counterparts of the surface plasmon polaritons (i.e., the transverse magnetic (TM) waves) which have been extensively studied in the last several decades. We show that TE waves with resonant wavelengths in the visible light spectrum can be excited in a dielectric-metal heterostructure when the optical thickness of the dielectric layer exceeds a critical value. We reveal that the electric and magnetic field distributions for the TE waves are spatially separated, leading to higher quality factors or narrow linewidths as compared with the TM waves. We calculate the thickness, refractive index and incidence angle dispersion relations for the TE waves supported by a dielectric-metal heterostructure. In experiments, we observe optical resonances with linewidths as narrow as ∼10 nm in the reflection or scattering spectra of the TE waves excited in a Si3N4/Ag heterostructure. Finally, we demonstrate the applications of the lowest-order TE wave excited in a Si3N4/Ag heterostructure in optical display with good chromaticity and optical sensing with high sensitivity.

Realizing and manipulating strong light–matter coupling in two-dimensional monolayer semiconductors is important in the research of cavity quantum electrodynamics and the development of photonic/plasmonic devices. Here, we investigate the coupling between the transverse-electric (TE) polarized wave supported by a Si3N4/Ag heterostructure and the two excitons in a WS2 monolayer (i.e., the A- and B-excitons) attached on such a heterostructure. It is found that the dissipation rate of the TE wave can be modified by simply varying the thickness of the Ag film. By appropriately designing the thickness of the Ag film, the strong coupling between the TE wave and the two excitons in the WS2 monolayer can be simultaneously realized, leading to hybridization of the two excitons. We numerically simulate the angle-resolved reflection spectra for the WS2/Si3N4/Ag heterostructure and reveal hybridization of the two excitons mediated by the TE wave. In experiments, we introduce Au nanorods as scatters for the TE wave, which enhance the in-plane electric field and achieve stronger photon–exciton coupling. We experimentally measured the angled-resolved scattering spectra for an Au nanorod placed on the WS2/Si3N4/Ag heterostructure and demonstrated the strong coupling between the TE wave and the two excitons, which results in the hybridization of the two excitons. Our findings open horizons for realizing and manipulating strong light–matter interaction in two-dimensional materials and pave the way for the construction of photonic/plasmonic devices by exploiting dielectric–metal heterostructure. [ABSTRACT FROM AUTHOR]

The novel orange‐red light‐emitting garnet‐type phosphors Li3Bi3Te2O12:xSm3+ (0.005 ≤ x ≤ 0.25) were first synthesized using the high‐temperature solid‐state reaction method. The phase structure was recorded with XRD. Raman spectroscopic analysis was conducted for the first time to extract detailed structural insights of the tellurate garnet Li3Bi3Te2O12:Sm3+. The characteristics of the obtained compounds were investigated, including particle morphology, elemental mapping, diffuse reflection spectra, excitation and emission spectra, thermal stability, chromaticity coordinates according to the Commission International del′Eclairage, and color purity. The Li3Bi3Te2O12:Sm3+ phosphor could be effectively excited by 406 nm irradiation, and four sharp peaks were presented. The dominant peaks are located at 613 and 653 nm, corresponding to the typical transition of Sm3+ ions at 4G5/2→6H7/2 and 4G5/2→6H9/2, respectively. The phosphors present a regular concentration quenching trend, with an optimum Sm3+ doping concentration of 0.02. Impressively, the product demonstrates remarkable thermal stability by maintaining an emission intensity of 93% at a working temperature of 423 K. Additionally, the thermal quenching temperature (T0.5) surpasses 480 K. The lighting performance of the white light‐emitting diode fabricated using Li3Bi3Te2O12:0.02Sm3+ phosphor has been found to be exceptional, characterized by a high color rendering index (Ra = 90) and a low correlated color temperature (CCT = 5122 K). The electroluminescent spectrum of the red light‐emitting diode device fabricated by Li3Bi3Te2O12:0.02Sm3+ overlapped well with the absorption spectra of the phytochromes, suggesting its potential for plant cultivation light source. In conclusion, considering all these photoluminescent properties mentioned above, Li3Bi3Te2O12:Sm3+ phosphor can be regarded as a promising material for daily illumination and plant cultivation LEDs. [ABSTRACT FROM AUTHOR]