Light, science & applications最新文献

Atomically thin semiconductors exhibit tunable exciton resonances that can be harnessed for dynamic manipulation of visible light in ultra-compact metadevices. However, the rapid nonradiative decay and dephasing of excitons at room temperature limit current active excitonic metasurfaces to a few-percent efficiencies. Here, we leverage the combined merits of pristine 2D heterostructures and non-local dielectric metasurfaces to enhance the excitonic light-matter interaction, achieving strong and electrically tunable exciton-photon coupling at ambient conditions in a hybrid-2D excitonic metasurface. Using this, we realize a free-space optical modulator and experimentally demonstrate 9.9 dB of reflectance modulation. The electro-optic response, characterized by a continuous transition from strong to weak coupling, is mediated by gating-induced variations in the free carrier concentration, altering the exciton's nonradiative decay rate. These results highlight how hybrid-2D excitonic metasurfaces offer novel opportunities to realize nanophotonic devices for active wavefront manipulation and optical communication.

Optical rotators based on the Faraday effect have been widely used in optical systems, such as optical isolation and circulators. However, due to the limitation of crystals, the application of such optical rotators in high-power lasers has been severely hindered. Here, we propose a novel plasma rotator based on the frequency-variable Faraday rotation (FVFR) in a compact manner, achieved by driving the magnetized underdense plasma with a relativistic linearly polarized laser. In the magnetized plasma, the drive laser undergoes photon deceleration and relativistic Faraday rotation, leading to the generation of relativistic polarization-tunable mid-infrared (mid-IR) pulse with intensity $\ge {10}^{16}$ W cm^-2 and a spectral width of 5-25 μm. With different magnetic fields, the polarization angle of the generated mid-IR pulse can be well controlled. Especially, one can obtain a circularly polarized mid-IR pulse with the spatial average polarization degree of $\ge 0.94$ at a suitable external magnetic field. The robustness of the rotator has been well demonstrated through comprehensive three-dimensional particle-in-cell simulations across a wide range of laser and plasma parameters. Such a rotator via FVFR is valid from mid to far-infrared and even THz waveband, offering new opportunities for strong-field physics, attosecond science, laboratory astrophysics, etc, and paving the way for relativistic plasma magneto-optics and future relativistic plasma optical devices.

Computational fluorescence microscopy constantly breaks through imaging performance through advanced optical modulation technologies; however, conventional theoretical modeling and experimental measurement approaches are challenging to meet the demand for accurate system characterization of diverse modulations. To this end, we propose a point spread function (PSF) decoupling method that is intrinsically compatible with the optimal demodulation in computational microscopic imaging modality. The critical core lies in designing a sample prior-based computational imaging strategy, in which a regular fluorescent sample instead of generally used sub-diffraction limited particles acts as a system modulator to demodulate the system response. PSF consequently can be computationally optimized through the strong support from the modulated sample prior, achieving accurate non-parametric system characterization and thereby avoiding the modeling difficulty and the low signal-to-noise ratio measurement errors of the system specificity. Experimental results across various biological tissues demonstrated and verified that the proposed PSF decoupling method enables excellent volumetric imaging comparable to confocal microscopy and multicolor, large depth-of-field imaging under aperture modulation. It provides a promising mechanism of system characterization and computational demodulation for high-contrast and high-resolution imaging of cellular and subcellular biological structures and life activities.

Polarized topological vertical cavity surface-emitting lasers (VCSELs) are promising candidates for stable and efficient on-chip light sources, with significant potential for advancing optical storage and communication technologies. However, most semiconductor-based topological lasers rely on intricate fabrication techniques and face limitations in providing the flexibility needed for diverse device applications. By drawing an analogy to two-dimensional Semenov insulators and the quantum valley Hall effect in a synthetic parameter space, we design and realize a one-dimensional optical superlattice using stacked polymerized cholesteric liquid crystal films and Mylar films. Such a one-dimensional optical superlattice is achieved by using films spin-coated with a Pyrromethene 597 solution, thus enabling the demonstration of a structure-flexible, low threshold, and circularly-polarized topological VCSEL. We demonstrate that such a topological VCSEL maintains excellent single-mode operation at low pump power, and its spatial profile aligns closely with that of the pump laser. Thanks to the soft-matter-based metastructure, the topological laser can be "attached" to substrates of various shapes, maintaining desired laser properties and beam steering even after undergoing multiple bends. These characteristics make the demonstrated topological laser ideal for applications in consumer electronics, laser scanning, displays, and photonic wearable devices, where both flexibility and performance are crucial.

A dynamically programmable, nonlinear beam-shaping and steering system is demonstrated, based on photopatterned, electrically controlled, ion-doped liquid ferroelectrics. This innovative approach elevates the linear liquid-crystal Pancharatnam-Berry optics to the reconfigurable nonlinear Pancharatnam-Berry optics regime, creating new possibilities for dynamic light-matter interactions, multiplexing holography, tunable quantum optics, and many other reconfigurable photonic applications.

Orbital angular momentum, as an important spatial degree of freedom of light, has prompted various promising applications. The recently proposed generalized vortex beams may further enhance the flexibility by utilizing customer-defined angular phase gradients, enabling intuitive graphic representation of mathematical operations and other interesting functionalities. Here, based on Dammann optimization, we propose and demonstrate a three-dimensional generalized vortex beam array using a single-layer metasurface, with all-parameter modulation including polarization, phase, angular momentum, and stereoscopic space. Furthermore, simultaneous vectorial modulation within each order can be endowed through joint optimization to achieve arbitrary polarization information distribution. This novel approach to generating the 3D generalized vortex beam array offers great flexibility in utilizing multiple degrees of freedom of light, further expanding the information capacity and spatial mode features and facilitating applications such as optical wireless broadcasting, optical communication encryption, structured beam manipulation, etc.

Available transducers do not fulfill all of the necessary design criteria for high-performance hemispherical optoacoustic tomography, namely: an ultrawide bandwidth in order to acquire the full range of optoacoustic emissions from targets of interest, good impedance matching to minimize reverberation artifacts, and a modifiable form factor, for inclusion in non-flat geometries. Polyvinylidene fluoride (PVDF) transducers can, in principle, meet all of these criteria, but PVDF has known shortcomings. In Ultrawideband high-density polymer-based spherical array for functional optoacoustic micro-angiography, all of the challenges of working with PVDF are overcome with the demonstration of a high-performance PVDF-based hemispherical optoacoustic tomographic system.

The pursuit of high-quality single-photon sources has long been hampered by challenges in improving the performance and robustness. While traditional microcavity structures can achieve impressive performance, they suffer from extreme sensitivity to manufacturing uncertainty, structural disorders, and scatterings. Topological photonics potentially offers a powerful toolbox for solving these problems. A recent breakthrough by researchers from the Beijing Academy of Quantum Information Sciences, published in Light: Science & Applications, exploits a topological bulk state rather than the already reported edge and corner states to enhance the single photon emission for a quantum dot.

Triplet dynamics play a key role in room temperature phosphorescence (RTP) and thermally activated delayed fluorescence (TADF). In this work, we report a model emitter with three emission components: prompt fluorescence (PF) in nanoseconds, delayed fluorescence in microseconds, and RTP in milliseconds, with the emission spectrum ranging from ultraviolet to deep blue. We experimentally and theoretically verify that a second triplet excited state, T₂, below the singlet state S₁ is involved in facilitating simultaneous PF, TADF, and RTP in the model emitter. The reverse intersystem crossing (rISC) from T₂ to S₁ contributes to the TADF, while the radiative transition from T₁ to the ground state is the origin of the long-lived RTP. By transferring the energy of multiple excited states to a series of conventional fluorescence emitters, a multi-color emissive system covering the entire visible wavelength range has been realized, with the photoluminescence decay ranging from 10^-9 s to 10^-1 s. By slightly tuning the energy difference between these excited states in the model molecule, a highly efficient organic luminescent material with only PF and RTP emission has been obtained with an RTP quantum yield above 30%. This work provides insights into the key role of higher-lying triplet states in the development of efficient TADF and RTP materials.

Dynamic photoprogramming of paintable liquid crystal photonic devices with multi-stability shows practical application in smart soft materials and responsive optics. However, there exist three key challenges that limit their development: achieving precise paintability with controllable viscosity and resolution, maintaining well-ordered liquid crystal photonic structures, and enabling multi-stable photoresponsive behavior. Here, we address these limitations by incorporating an intrinsic photoswitch into a cellulose-based liquid crystal system, further constructing a unique paintable helical photonic architecture featuring both multi-stability and dynamic light-actuation. The intrinsic chiral photoswitch enables multi-stable modulation of helical pitch, while optimized viscosity restrains the remarkable fluidity of traditional liquid crystal systems and matches proper surface anchoring, thereby allowing for paintability and programming of a photonic device. The cutting-edge single-step painting enables highly efficient, large-area and well-defined patterning of helical architectures on diverse flexible substrates, thereby promoting prospective applications in anti-counterfeiting, information encryption, and smart window-film. This strategy establishes a robust and versatile foundation that integrates practical explorations in soft matter photonics with state-of-the-art engineering applications, such as multifunctional interactive optical information systems and advanced intelligent flexible sensors.