Yuebing Zheng

On-chip silicon light sources are highly desirable for integrated photonics but remain challenging due to silicon’s indirect bandgap and low radiative efficiency. Amorphous silicon supports photoluminescence via band-tail states, yet lacks scalable cavity platforms for efficient light extraction and control. Here, we demonstrate solution-synthesized amorphous silicon microspheres that simultaneously serve as the luminescent medium and spherical optical cavity within a compact ~1 μm³ volume. The spheres exhibit whispering-gallery-mode-coupled photoluminescence, with resonances spanning 800–1100 nm and a maximum measured quality factor of 522, producing narrow and spectrally resolved emission peaks at room temperature. The emission exhibits active tunability through temperature, surrounding refractive index, and excitation power, reflecting the sensitivity of the WGM resonances to thermal and dielectric perturbations. Moreover, the microspheres are readily integrated with three-dimensionally printed waveguides, enabling on-chip routing of emitted light. These features position amorphous silicon microspheres as a versatile, room-temperature platform, offering cavity-enhanced emission and broad tunability for next-generation integrated photonic systems.

Controlled rotation of single biological cells is significant for cellular biology and engineering. Here we present a light-driven and non-contact strategy that enables arbitrary-axis rotation of both spherical and anisotropic cells with real-time switching between distinct rotation modes (major-axis and minor-axis). The platform employs a Bovine Serum Albumin (BSA)-coated gold nano-island (AuNIs) plasmonic film to generate strong interfacial thermo-osmotic flow under laser illumination, while Polyethylene Glycol (PEG)-induced depletion forces confine cells near the interface. For spherical particles, arbitrary-axis rotation is achieved using a single Gaussian beam, where spatial asymmetry in the thermo-osmotic flow determines the rotation axis. For anisotropic cells, different rotation modes are enabled by optical pattern reconfiguration. A Gaussian beam induces major-axis rotation, while a half-ring beam generates a combined optical and thermo-osmotic torque distribution that supports sustained minor-axis rotation. The rotation mode is reversibly switched solely through optical reconfiguration without mechanical intervention. This unified platform establishes geometry-independent, optically programmable rotational control, opening new opportunities for high-speed multi-angle cellular imaging and dynamic studies of cell-cell interactions.

The deterministic and reconfigurable assembly of heterogeneous micro- and nanostructures remains challenging, where Brownian motion, nonspecific interfacial adsorption, and method-specific material constraints undermine precision and cross-material compatibility. Here, we present ice-phase optothermal tweezers (IOT), a platform that utilizes the ice–water interface for fast (10–100 μm/s), programmable manipulation of diverse targets, including dielectric/metal nanoparticles, proteins, DNA, and even microbubbles within ice, which have long been regarded as passive byproducts of freezing. In this scheme, the optothermally induced mobile melting zone within the ice matrix enables directed transport and nanostructure assembly with nanometer-scale resolution. We further fabricate multi-material heterostructures with tailored anisotropic and chiral optical responses, enabling applications in chiral photonics and polarization-controlled nano-optical devices under cryogenic environments. Accordingly, by unifying precise control of micro- and nano-entities across fluidic and solid-state regimes, IOT provides a general cryogenic platform for meta-structure fabrication, in-situ optical spectroscopy, and nanoparticle-interaction studies.

Subtractive nanomanufacturing is essential for high-precision device fabrication, but conventional techniques rely on resource-intensive processes and environmentally hazardous materials. Here, we introduce Optothermal Bubble Etch Lithography (OBEL), a single-step, maskless technique that enables localized, high-resolution patterning with minimal chemical and thermal damage. OBEL uses a low-power continuous-wave laser focused on a gold film to generate microbubbles at the substrate-liquid interface, which locally concentrate etchant ions for spatially selective etching. Solutal Marangoni convection actively removes bubbles and generated debris, yielding clean and sharply defined features. Operating at ultralow etchant concentrations (0.05 M), OBEL achieves complex planar patterns with submicron (∼450 nm) resolution. This environmentally friendly, cost-effective lithography method offers a scalable alternative for micro- and nanoscale fabrication across electronics, photonics, and biomedical applications.

Programming light flow offers significant potential for diverse applications. However, conventional spatial light modulators are bulky, have large pixels, and slow switching. Miniaturized metasurface strategies offer flexibility but are limited to radial or azimuthal phase gradients, hindering free shaping of light flow in ultracompact footprints. Here, we present a meta-conveyor technique (MCT) using metasurfaces to encode user-defined optical flow, demonstrating programmable stable transport of nanoparticles (NPs) with arbitrary open-path round‑trip movement and on‑demand stopping. Theoretical analysis reveals efficient phase gradient switching from hybrid propagation and geometric phases, enabling tunable lateral optical forces via input and output polarization control. We validate universality with a maze‑solving meta‑conveyor that drives NPs from entrance to exit while avoiding dead ends. The MCT provides a compact, passive platform for programmable on‑chip manipulation, opening avenues for heterogeneously integrated clinical devices in minimally invasive and extreme environments.

Surface lattice resonances (SLRs) in metasurfaces have become a transformative platform for subwavelength optical devices. However, current high quality-factor (high-Q) SLR implementations are fundamentally limited by their dependence on homogeneous dielectric environments. To overcome this limitation, we introduce guided-surface lattice resonances (gSLRs) by integrating nanoparticle arrays within slab waveguides. This configuration facilitates efficient coupling between scattered light and Bloch modes, enabling high-Q multimodal resonances even in index-discontinuous environments, realizing a quality-factor (Q-factor) of 1489. The coupling strength and resonance intensity of these multimodal gSLRs can be continuously modulated by adjusting the vertical displacement of the nanoparticle arrays within the slab layers. To augment the sensitivity to local dielectric variations, we investigate gSLRs in metasurfaces integrated with metallic substrates, demonstrating suitability for biosensors. A mathematical sensing model, incorporating biochemical reaction kinetics and optical responses, is established and validated through bovine serum albumin (BSA) sensing, achieving a limit-of-detection as low as 0.65 pM.

Acoustic tweezers can transport particles along arbitrarily defined paths with unprecedented robustness across defects and sharp corners.

Colloidal particles emerge as promising building blocks for the construction of novel materials and devices owing to their tailorable morphologies, abundant species, and intriguing properties. In comparison to other assembly approaches, optical colloidal assembly relies on photophysical or photochemical interactions and allows the arrangement of particles into desired geometries on a substrate with high spatial and temporal resolution. Typically, optical colloidal assembly involves two major processes, i.e., optical manipulation for colloidal arrangement and light-triggered interparticle bonding for colloidal immobilization. In this review, we first categorize the optical manipulation techniques based on different working principles and discuss their technical features and assembly capabilities. We then provide a comprehensive overview of different colloidal bonding schemes, including van der Waals attraction, dipole-dipole interaction, biochemical linking, photopolymerization, and surface ligand bonding. Finally, we summarize the cutting-edge applications of assembled colloidal structures and end with our vision for the existing challenges and future development in this field.

Precise and scalable enrichment of dispersed analytes is vital for biosensing, environmental monitoring, and nanomaterial processing. However, current methods often lack versatility and spatial resolution. Here, we introduce optothermal ice-water interface management (OIIM), a universal, label-free approach for cross-scale enrichment and sensing. By optically guiding a movable ice-water interface, OIIM creates a tunable and controllable nanovessel that actively drives analytes, from angstrom-scale dyes to micrometer-scale particles, into confined regions. This versatile approach efficiently enriches diverse targets, including nucleotides, proteins, and synthetic nanomaterials. Molecular dynamics simulations and fluorescence imaging have been investigated to elucidate the solute-interface interactions and the enhanced interfacial trapping underlie the observed enrichment behavior. Furthermore, OIIM supports multisite enrichment, spatial consolidation, and the formation of femtoliter-scale microreactors for accelerated enzyme-cascade reactions. Notably, OIIM offers unique capabilities for enriching and analyzing ultrashort nucleic acids that elude conventional purification methods, establishing a flexible, molecular-level optothermal strategy within ice.