Lead halide perovskites exhibit extraordinary optoelectronic performances and are being considered as a promising medium for high‐quality photonic devices such as single‐mode lasers. However, for perovskite‐based single‐mode lasers to become practical, fabrication and integration on a chip via the standard top‐down lithography process are strongly desired. The chief bottleneck to achieving lithography of perovskites lies in their reactivity to chemicals used for lithography as illustrated by issues of instability, surface roughness, and internal defects with the fabricated structures. The realization of lithographic perovskite single‐mode lasers in large areas remains a challenge. In this work, a self‐healing lithographic patterning technique using perovskite CsPbBr3 nanocrystals is demonstrated to realize high‐quality and high‐crystallinity single‐mode laser arrays. The self‐healing process is compatible with the standard lithography process and greatly improves the quality of lithographic laser cavities. A single‐mode microdisk laser array is demonstrated with a low threshold of 3.8 µJ cm−2. Moreover, the control of the lasing wavelength is made possible over a range of up to 6.4 nm by precise fabrication of the laser cavities. This work presents a general and promising strategy for standard top‐down lithography fabrication of high‐quality perovskite devices and enables research on large‐area perovskite‐based integrated optoelectronic circuits.

Plasmonic nanolasers provide a valuable opportunity for expanding sub‐wavelength applications. Due to the potential of on‐chip integration, semiconductor nanowire (NW)‐based plasmonic nanolasers that support the waveguide mode attract a high level of interest. To date, perovskite quantum dots (QDs) based plasmonic lasers, especially nanolasers that support plasmonic‐waveguide mode, are still a challenge and remain unexplored. Here, metallic NW coupled CsPbBr3 QDs plasmonic‐waveguide lasers are reported. By embedding Ag NWs in QDs film, an evolution from amplified spontaneous emission with a full width at half maximum (FWHM) of 6.6 nm to localized surface plasmon resonance (LSPR) supported random lasing is observed. When the pump light is focused on a single Ag NW, a QD‐NW coupled plasmonic‐waveguide laser with a much narrower emission peak (FWHM = 0.4 nm) is realized on a single Ag NW with the uniform polyvinylpyrrolidone layer. The QDs serve as the gain medium while the Ag NW serves as a resonant cavity and propagating plasmonic lasing modes. Furthermore, by pumping two Ag NWs with different directions, a dual‐wavelength lasing switch is realized. The demonstration of metallic NW coupled QDs plasmonic nanolaser would provide an alternative approach for ultrasmall light sources as well as fundamental studies of light matter interactions.

Plasmonic-waveguide lasers, which exhibit subdiffraction limit lasing and light propagation, are promising for the next-generation of nanophotonic devices in computation, communication, and biosensing. Plasmonic lasers supporting waveguide modes are often based on nanowires grown with bottom-up techniques that need to be transferred and aligned for use in optical circuits. Here, we demonstrate a monolithically fabricated ZnO/Al plasmonic-waveguide nanolaser compatible with the fabrication requirements of on-chip circuits. The nanolaser is designed with a plasmonic metal layer on the top of the laser cavity only, providing highly efficient energy transfer between photons, excitons, and plasmons, and achieving lasing in the ultraviolet region up to 330 K with a low threshold intensity (0.20 mJ/cm 2 at room temperature). This work demonstrates the realization of a plasmonic-waveguide nanolaser without the need for transfer and positioning steps, which is the key for on-chip integration of nanophotonic devices.

A reliable fabrication technique for obtaining a high density of regular nanogaps is critical for ultrasensitive surface-enhanced Raman scattering (SERS). However, nanogaps produced between nanostructures have suffered from the lack of controllability. Taking the sphere−film structure as a starting point for its straightforward fabrication technique and well-controlled gaps, we propose a novel nanostructure by combining Au nanospheres and inverse pyramidal holes. The proposed nanostructure is obtained by trapping Au nanospheres in inverse pyramidal hole arrays to create multiple, uniform, and reproducible geometrical gaps near the contact points between the nanospheres and the inverse pyramids. The combined nanostructure, referred to as SIP (spheres in pyramids), supports augmented plasmon hybridization due to mirroring of gap plasmons and induces much stronger electromagnetic enhancement at normal incidence when compared to the contacting sphere−film structure. In contrast to the sphere−film structure exhibiting a maximum enhancement for slant incidence, the SIP achieves a maximum enhancement at normal incidence. The effective plasmon hybridization from SIP arrays sustains SERS intensities 9 times stronger than those of conventional contacting sphere−film structures and achieves 64% of the total electromagnetic field enhancement obtained from the sphere−spacer−film structure with a 0.6−0.8 nm thick spacer.

Extensive studies on lead halide perovskites have shown that these materials are excellent candidates as gain mediums. Recently, many efforts have been made to incorporate perovskite lasers in integrated optical...