Programmable Aperture Light-Field Microscopy

In article number 2300217, Qian Chen, Chao Zuo, and colleagues describe a computational three-dimensional (3D) microscopy technique. The proposed incoherent Fourier slice theorem describes that annular aperture modulation (foreground) can transform the captured 2D image spectrum of the observed sample into a central slice of the 3D object spectrum (background). Through tomographic reconstruction, 3D information of the sample can be high-resolution, multi-color retrieved without requiring complicated sample rotation or beam scanning.

Height-Gradiently-Tunable Nanostructure Arrays by Grayscale Assembly Nanofabrication for Ultra-realistic Imaging

The height gradient of nanostructures can hardly be achieved due to the limitations of fabrication techniques. In article number 2300073, Ruhao Pan, Junjie Li, and colleagues present a grayscale assembly nanofabrication method, which can fabricate nanostructures with independently controlled height and the other features, and high-resolution grayscale images and structural color metasurfaces are realized by the proposed method. Grayscale assembly nanofabrication provides a new dimension for light regulation and shows great potential in nanophotonic devices.

Emergent Phenomena of Vector Solitons Induced by the Linear Coupling

Vector solitons are ubiquitous in optical systems supporting two modes with nonlinear interactions. In article number 2300076, Yueqing Du, Dong Mao, Jianlin Zhao, and colleagues investigate the vector soliton under linear coupling introduced by a simple polarization controller in the fiber laser. Brand-new phenomena such as breathing and chaotic vector solitons are revealed to be controlled by linear coupling. The complex dynamics can be understood as emergent phenomena induced by a simple interaction between two polarization modes. The work gives new insight into the two-mode nonlinear system and has the potential for intelligent manipulation of ultrafast lasers.

Antireflection Spatiotemporal Metamaterials

In article number 2300130, Hao Hu, Lei Gao, Dongliang Gao, and colleagues propose a spatiotemporal metamaterial to fully suppress the reflection and realize frequency conversions. The spatiotemporal metamaterials with two dynamic interfaces are engineered simultaneously in space and time by the pump beams, which are obliquely incident onto the metamaterials.

Mie scattering is a fascinating phenomenon that occurs when light meets a nanoparticle of a size comparable to its wavelength. It leads to remarkable optical effects and has a long list of applications in photonics and optoelectronics. In this work, a review of the Mie scattering from basic solution of light scattering on a sphere to more complex effects and their applications is made.

Real-time investigation of ultrafast dynamics in mode-locked fiber lasers (MLFLs) reveals various fascinating phenomenon before, during, and after formation of stable laser pulses. These dynamics are studied via the dispersive Fourier transform technique, which maps the spectral information of a MLFL into a time-stretched waveform. This review provides deep insight into the evolution process, different types, and complex motion dynamics in MLFL.

This review delves into the fascinating field of soft-matter photonics, highlighting recent advances in nonlinear liquid-core fiber optics. It covers the start-of-art in design, modeling, fabrication, and application of optical fibers with exceptional transparency, nonlinearity, and reconfigurability introduced by solvents as fiber material. Unique phenomena in liquid-core fibers and their potential as a platform for innovation are also discussed.

Programmable aperture light-field microscopy (PALFM) for motion-free, high-resolution volumetric imaging is proposed. The well-known Fourier slice theorem is extended to incoherent tomographic imaging, and a hybrid aperture modulation scheme is designed for high-efficiency, non-ambiguous depth discrimination. PALFM is experimentally demonstrated to be an effective microscopic tomographic imaging modality for studying the morphology and dynamics of cellular and subcellular organisms.

A grayscale assembled nanofabrication (GANF) method based on the grayscale lithography and atomic layer deposition filling is developed for the fabrication of height gradient nanostructures with multi-dimensional controlled features, which have been used in high-resolution grayscale imaging and structural color metasurface based on the abundant spatial controllability. The GANF method inspires a new mode for the realization of nanophotonics devices.

By introducing linear coupling between two orthogonal modes in a ultrafast fiber laser, complex emergent phenomena are observed, presenting various intriguing dynamics of vector solitons, which can be controlled by the polarization controller. This work sheds light on the two-mode dynamics in the nonlinear dissipative system and has potential for intelligent manipulation of lasing states.

Eliminating the reflection from a spatiotemporal interfaceis still challenging. A new type of spatiotemporal metamaterial that functions as a global and generalized perspective of quarter-wave impedance transformers is proposed. The reflection can be fully suppressed, applicable to arbitrary modulation velocities. This work offers insights into controlling electromagnetic waves, elastic waves, acoustic waves, and surface waves.

Goos–Hänchen and Imbert–Fedorov optical beam shifts, with a rich history and fundamentally different origins, are shown to be non-separable. Consequently, a tunable position–position non-separable state emerges from a simple partial reflection of a Gaussian beam. The discovery is expected to enrich our understanding of classical analogues of entanglement and have impacts on applications involving metrology, information processing, and communication.

By applying arbitrary-waveform driving in a synthetic temporal lattice constructed using two coupled fiber loops, a generalized dynamic localization effect is identified and experimentally demonstrated. Based on this, diffraction-free temporal beam transport and refraction control are also achieved. This work provides promising applications for temporal waveform reshaping and optical pulse management.

A single temporal soliton is generated in a Z-cut ytterbium-doped lithium niobate (LN) microresonator. The optical spectrum of a soliton spans 180 nm in the telecom band and embraces 197.8 GHz-repetition rates. The mode-locking of the soliton pulse, whose width is fitted to be 44.5 fs, is readily achieved owing to the photorefractive effect of LN.

Temporal metamaterials in the form of thin temporal coatings enable ultra-fast quantum state frequency shifting as well as material switching without the amplification of thermal noise, opening new possibilities for the ultra-fast and noiseless manipulation of quantum states of light.

The high efficiency of the third harmonic generation is proved in the low refractive index regime, where phase-matching conditions are satisfied by default. As exemplified numerically, silicon-based photonic crystals can effectively generate the third harmonics, which can be outcoupled in any desired direction. Such an approach simplifies on-chip circuitry, unifying the whole production chain with implementation of the same material.

The spontaneous emission of an optical emitter is strongly affected by its surrounding radiative local density of optical states (r-LDOS). Bulk states of a z-direction asymmetric dielectric photonic crystal slab are probed with cathodoluminescence microscopy by characterizing r-LDOS with super nanoscale resolution, benefiting the nanoscale manipulation of light–matter interactions and the optimization of quantum emission devices.

Differentiable holography leverages experimental imperfections with differentiable programming to achieve inverse holographic imaging and estimate imperfections. It enables automatic focusing of complex field imaging using a single-shot intensity-only inline hologram.

A deep-subwavelength metasurface from the topological insulator Bi₂Te₃ is demonstrated, leveraging the experimentally measured ultra-high refractive index of n ≈ 11 with the fundamental magnetic dipole resonance confined in unit cell sizes smaller than λ/10. Dense Bi₂Te₃ metasurfaces can simultaneously provide large magnetic and electric field enhancements arising from the high index of the bulk and the surface metallic states.

Ultra-low noise single–longitudinal–mode lasers are prepared by combining atom-like gain material and lateral gratings, which also possess high output power, superior temperature stability, and strong tolerance to optical feedback. This work demonstrates the great potential of developing high-quality light sources with compact size for coherent optical communications, high-precision optical detection, and photonics integrated circuits, etc.

Entanglement is one of the most essential resources for quantum information. Improving its flexibility is important for its practical applications. In this article, an entanglement of six orbital angular momentum modes whose topological charges can be flexibly reconfigured is experimentally generated. The scheme provides a platform to construct reconfigurable quantum communication networks.

High-dimensional frequency encoding allows for transfer of much more information per photon than, e.g., just polarization encoding. However, the certification of high-dimensional frequency entanglement is not trivial. This work provides methods to quantify the amount of entanglement in a quantum frequency comb without the need for assumptions on the state, showing a record certification of at least 33 entangled modes.

Thermo-optic phase shifters are widely used in large-scale photonic integrated circuits, and the improvement of their thermal tuning parameters is crucial to the entire system. Here, a phase shifter based on a hydrogen-doped indium oxide (IHO) microheater is demonstrated. Its high performance and complementary metal-oxide semiconductor (CMOS)compatible processes endow it with great potential for on-chip large-scale integration applications.

An all-fiber, high-power spatiotemporal mode-locked oscillator based on MMFs is constructed and investigated. The maximum average output power of 1.16 W and the beam profile with M_x² = 1.18 and M_y² = 1.13 is obtained at dissipative soliton operation. The maximum average output power of 3.48 W and the beam profile with M_x² = 1.04 and M_y² = 1.23 is achieved at noise-like pulse operation.

Colloidal layered waveguide and microdisk structures are constructed using red- and green-emitting colloidal quantum wells as the active gain media. In their all-solution processed waveguide and cavity, dual-color amplified spontaneous emission and lasing are achieved, respectively. Here, the use of a lossless colloidal spacer between the gain media in a multilayered configuration is proved to be the key to effectively suppressing otherwise detrimental nonradiative energy transfer and enabling dual-color gain and lasing.

A single emissive layer white light-emitting diode for healthy daily lighting is designed based on Bi³⁺/Te⁴⁺ dual-doped Cs₂SnCl₆, which shows high working performance, alongside continuous regulation of the correlated color temperature for different application scenarios, constituting a solid step toward building the next generation of healthy and high-quality illumination.

Ultrabroadband multichannel vector vortex beams (VVBs) are generated by programming the electric field vector of transmitted light through the tailored twisted nematic liquid crystals. The satisfying working spectrum from visible to mid-IR regions is demonstrated. The versatile functionality is proposed in which the multichannel VVBs present either reversible or irreversible electrical switching behavior by conveniently regulating the applied voltage.

The experimental preparation and manipulation of optical cat states based on a remotely distributed two-mode Gaussian entangled state in lossy channels is demonstrated. Moreover, it provides a new method to prepare optical cat states with amplitude larger than 2. The presented results make a crucial step toward remote hybrid quantum information processing involving discrete- and continuous-variable techniques.

A spatial full degree-of-freedom optical field modulation against scattering is proposed that can control the amplitude, phase, and polarization of optical fields simultaneously. Against scattering environments, this thorough control over the optical field enables a high-contrast focusing, polarized holographic display, and orbital angular momentum control. This method holds great potential to advance the application of optical field modulation.

An efficient approach to simultaneously realize on-chip polarization and wavefront manipulation of far-field radiation based on guided wave-driven geometric metasurfaces is proposed and experimentally demonstrated, which shall provide a further step in the development of photonic integrated circuits, wearable near-eye displays, information encryption, and so on.

Phase retrieval problems of complex optical transmission matrices are tackled with pure intensity measurements. Through probabilistic phase shaping of the probing matrix, the transmission matrix of a multimode fiber is retrieved with information-limited intensity measurements, enabling efficient wavefront control including projecting single optical foci and synthesizing English letters at the distal end of the fiber.

A novel solution for controlling the global symmetry of the nonlinear meta-crystals is introduced by tuning the coupling strength of the adjacent meta-atoms. By designing the hexagonal boron nitride-like meta-crystals which consist of plasmonic meta-atoms with local inversion symmetry and tailoring the gap size between the adjacent meta-atoms, strong second harmonic generation radiations are experimentally observed.

Here, a novel methodology using a rear-position wavevector filter is proposed to achieve ultrathin, wide-angle, and high-resolution meta-imaging, which has been experimentally demonstrated in both the visible and near-infrared with a maximum diffraction-limited field-of-view of over 120°. It can be scaled to all spectral bands and has the potential to revolutionize the design paradigm of imaging systems.

The metasurface of a large-scale unit has limited potential for compactness and miniaturization in free space. To solve this, a tiny metasurface made of patterned 2D electron gas microstructures is embedded in a waveguide to create an integrated electronic device that enables high-speed modulations via guided terahertz waves on a time scale of 40 ps.

A high-efficiency and tunable surface plasmon source is developed using a thickness gradient hyperbolic meta-antenna made of metamaterial. The quasi-hyperbolic isofrequency surface enables a cross-over between the very high wavevectors distribution of the local density of optical states and radiation efficiency. The performance of the system, as estimated by determining the maximum external quantum efficiency, is more than 20%.

A synergistic defect engineering approach is described for systematic tuning of persistent luminescence (PersL) in CaZnOS. By combinatorial doping of various ions in double cationic sites of the host lattice, PersL with tunable emission wavelength, intensity, and spectral evolution over time and temperature is achieved, demonstrating promising applications in information encryption and optical thermometry.

A new trimodal contrast agent for ultrasound, optoacoustic, and magnetic resonance imaging is developed in this study. The shell of submicron perfluoropentane droplets is encrusted with indocyanine green and magnetite nanoparticles using a layer-by-layer deposition approach. This structure is shown to generate a high signal in all three modalities both in phantom studies and in vivo.

Thermal quenching is a fatal drawback for near-infrared (NIR) phosphors. Here, the relation between bond angle distortion and thermal quenching is shown. The results demonstrate that minimizing bond angle distortion can be a new strategy to design thermal stable NIR phosphors.

Here, a single cesium lead tribromide halide-perovskite microwire is connected to symmetrical carbon-based electrodes generating a novel optoelectronic device. Under hybrid optoelectrical stimuli, the interfaces between the microwire and electrodes are modulated by photogenerated carriers and halide-perovskite mobile ions. This carrier synergy allows electroluminescent photodetection and light-enhanced electroluminescence phenomena. They uncovered the uniqueness of light-sensitive mixed ionic-electronic semiconductors for multifunctional optoelectronics.

Early Antoni van Leeuwenhoek's single ball lens microscopes revealed a new world of tiny living microorganisms, but subsequently became replaced with modern compound microscopes. This work revitalizes interest in single ball lenses with specially designed refractive indices as key elements of imaging by ordinary cellphones enabling submicron resolution of nanoplasmonic structures.

The performance of conventional mid-infrared spectrometers has long been hindered by the limited sensitivity of narrow-bandgap detectors and the deficient brightness of broadband light sources. Here, an upconversion-enabled mid-infrared dispersive spectrometer is implemented by leveraging a high-brightness nanophotonic supercontinuum, low-noise nonlinear conversion, and a high-sensitivity silicon detector, which leads to superior performances with broadband spectral coverage, single-photon sensitivity, and MHz-level frame rates.

Skyrmions are topologically protected field configurations characterized by a topological index. Here, an intuitive and geometrical method is proposed to determine the index for optical skyrmions solely via their polarization singularities and associated winding numbers. This method is confirmed experimentally and shown to provide increased accuracy and superior performance in the presence of noise compared to the conventional definition.

A matrix-based formalism is proposed to establish a fundamental bound on the transmission efficiency, based only on energy conservation and the desired functionality of a multi-channel optical system. Applying this formalism to diffraction-limited nonlocal metalenses reveals that reducing the size of the entrance aperture can raise the efficiency bound.

Interesting monochromatic and full-color pixelated phosphor converters are prepared by producing arrayed holes in the Ag substrate with the laser direct writing technology and filling the holes with the mixture of phosphor particles and heat-resisting inorganic glue. The realization of laser-driven white pixel light and full-color pixel light has great potential for use in the intelligent adaptive lighting.