Mechanical strain formed at the interfaces of thin films has been widely applied to self‐assemble 3D microarchitectures. Among them, rolled‐up microtubes possess a unique 3D geometry beneficial for working as photonic, electromagnetic, energy storage, and sensing devices. However, the yield and quality of microtubular architectures are often limited by the wet‐release of lithographically patterned stacks of thin‐film structures. To address the drawbacks of conventionally used wet‐etching methods in self‐assembly techniques, here a dry‐release approach is developed to roll‐up both metallic and dielectric, as well as metallic/dielectric hybrid thin films for the fabrication of electronic and optical devices. A silicon thin film sacrificial layer on insulator is etched by dry fluorine chemistry, triggering self‐assembly of prestrained nanomembranes in a well‐controlled wafer scale fashion. More than 6000 integrated microcapacitors as well as hundreds of active microtubular optical cavities are obtained in a simultaneous self‐assembly process. The fabrication of wafer‐scale self‐assembled microdevices results in high yield, reproducibility, uniformity, and performance, which promise broad applications in microelectronics, photonics, and opto‐electronics.

perovskites have been proposed as materials capable of improving the stability and surpassing the radiative recombination efficiency of threedimensional perovskites. However, their luminescent properties have often fallen short of what has been expected. In fact, despite attracting considerable attention for photonic applications during the last two decades, lasing in 2D perovskites remains unclear and under debate. Here, we were able to improve the optical gain properties of 2D perovskite and achieve optically pumped lasing. We show that the choice of the spacer cation affects the defectivity and photostability of the perovskite, which in turn influences its optical gain. Based on our synthetic strategy, we obtain PEA 2 SnI 4 films with high crystallinity and favorable optical properties, resulting in amplified spontaneous emission (ASE) with a low threshold (30 μJ/cm 2 ), a high optical gain above 4000 cm −1 at 77 K, and ASE operation up to room temperature.

Controlling the flow of light emitted from structures in micro/ nanoscale is crucial for on-chip active photonic devices and their tremendous applications. Although previous reports focus on improving the directionality along a fixed angle, the realization of flexible directional emission becomes highly desired for simultaneously manipulating multiple light flows with different properties (e.g., wavelength, polarization, and wavevector), which paves the way to emerging two and one-half dimensional and three-dimensional (3D) integrated photonics technologies. Here, we propose self-rolled-up nanomembrane-based asymmetric cavities with a deliberately controlled spiral shape and demonstrate 3D directional light emissions. The interaction between 3D confined optical resonances and a spiral nanomembrane edge results in deterministic yet tunable emission directions. Polarization-selective directionality as well as the transition between bi-and unidirectional emission regimes is revealed by adjusting the cavity confinement and mode chirality. The spiral nanomembrane cavities featuring adjustable structural asymmetry provide new insights into chiral light-matter interaction and manipulating light emission for multiplexed classical and quantum light sources.

We report the mode interactions and resonant hybridization in nanomembrane-formed concentric dual ring cavities supporting whispering gallery mode resonances. Utilizing a rolled-up nanomembrane with subwavelength thickness as an interlayer, dual concentric microring cavities are formed by coating high-index nanomembranes on the inner and outer surfaces of the rolled-up dielectric nanomembrane. In such a hybrid cavity system, the conventional fundamental mode resonating along a single ring orbit splits into symmetric and antisymmetric modes confined by concentric dual ring orbits. Detuning of the coupled supermodes is realized by spatially resolved measurements along the cavity axial direction. A spectral anticrossing feature is observed as a clear evidence of strong coupling. Upon strong coupling, the resonant orbits of symmetric and antisymmetric modes cross over each other in the form of superwaves oscillating between the concentric rings with opposite phase. Notably, the present system provides high flexibilities in controlling the coupling strength by varying the thickness of the spacer layer and thus enables switching between strong and weak coupling regimes. Our work offers a compact and robust scheme using curved nanomembranes to realize novel cavity mode interactions for both fundamental and applied studies.

Efficient radiative recombination is essential for perovskite luminescence, but the intrinsic radiative recombination rate as a basic material property is challenging to tailor. Here we report an interfacial chemistry strategy to dramatically increase the radiative recombination rate of perovskites. By coating aluminum oxide on the lead halide perovskite, lead–oxygen bonds are formed at the perovskite‐oxide interface, producing the perovskite surface states with a large exciton binding energy and a high localized density of electronic state. The oxide‐bonded perovskite exhibits a ≈500 fold enhanced photoluminescence with a ≈10 fold reduced lifetime, indicating an unprecedented ≈5000 fold increase in the radiative recombination rate. The enormously enhanced radiative recombination promises to significantly promote the perovskite optoelectronic performance.