Single-crystal diamond has attracted much attention because of its wide bandgap and specific thermal and optical properties, which is suitable for the utilization on integrated photonic devices and power semiconductor devices. However, its extremely high hardness confines the processing ability of micro/nano structures, which is the main determinant of devices performance. Here, multimode patterning methods using ultrafast laser regulated in spatial-domain with high precision are proposed. Through designing of spatial beam phase, specific patterned micro/nano structures ranging from sub-micrometer scale to millimeter scale can be printed on diamond surface with improved efficiency. This provides a facile strategy for the fabrication of programmable patterns with sub-wavelength resolutions. The laser ablation and graphitization result can be precisely predicted by calculating free electron density and validated through patterning experiment. A diamond holographic element is designed and fabricated through the proposed method, which can project the reconstructed holographic image for display applications. This work presents a promising method for preparing of single-crystal diamond-based next-generation semiconductor devices and integrated photonic systems requiring precise light field control.

Laser surface colorization has been regarded as a promise technology for inkless printing due to its advantages such as versatile, stable and environmentally friendly. However, the further applications of laser colorization in real industrial manufacturing are limited by inevitable trial and error procedure in experiment. Here, a prediction and inverse design of laser surface colorization process are realized to address this challenge by using a Color-Morphology Coupled Neural Network (CMCNN). The forward prediction is conducted by a Physical-guided Multilayer Perceptron (PG-MLP) with improved prediction accuracy. For solving the non-uniqueness of inverse design procedure, a Convolution Neural Network (CNN) based on the input physical image is utilized. This enables the combining of structural color and morphology information in input physical image for processing parameters planning. The network performance is verified through the fabrication of portrait and artwork image. The corresponding relationship between target color and experimental results demonstrate the validity of proposed model. This approach may open new possibilities for the fast and precise surface colorization, and facilitate the development of laser structure fabrications in practical engineering applications.

Nanometallic materials have attracted wide research attention in the fabrication of functional devices, including flexible electronics circuits and high-sensitive sensors. Sintering of nanometallic materials is generally thought as an effective technology for the functional manufacturing, and the controllable sintering of nanometallic materials and its major mechanisms have long been a challenge. Here, an ultrafast laser processing strategy for Ag nanoparticles (NPs) is achieved by modulating plasmonic. The excitation mode of plasmon can be designed by laser parameters, including polarization with a specific crystal size. The atomic-scale ultrafast dynamics are revealed for understanding the sintering process and design of the sintered structures. The non-equilibrium energy transfer between electron and lattice and dynamic evolution of pressure are proved to be the foremost driving forces on the motion of atomic structures. Through research of plasmonic-induced electric field enhancement and non-uniform deposition of heat and in-situ observation of relative transmittance, mapping from atomic-scale structure to micro behavior is established. Based on plasmonic modulation and processing of Ag NPs, a machine learning combined flexible gesture sensor with high recognition accuracy is displayed. This work expands the knowledge of interactions between lasers and nanometallic materials and provides a method for designing functional devices for a wide range of applications.

Interlayer modification between the perovskite and charge transport layers is critical to minimize trap-assisted recombination losses and promote highly efficient and stable perovskite solar cells. However, the cost and complexity of most modification materials limit the rapid development of perovskite photovoltaic technology. In this study, we propose Tris(1-chloro-2-propyl) phosphate (TCPP) as a cost-effective and efficient solution for interfacial modification. Theoretical calculations and experimental results demonstrate that the P=O group in TCPP effectively passivate both deep energy level defects and shallow defects of perovskite. This interaction enhances crystallinity, leading to high-quality films and improved solar cell efficiencies, achieving up to 20.73%. Our work presents the potential of organic molecules constructed with P=O group for enhancing both the efficiency and stability of perovskite solar cells, paving the way for their commercial viability.

Ultrafast laser processing technology has offered a wide range of opportunities in micro/nano fabrication and other fields such as nanotechnology, biotechnology, energy science, and photonics due to its controllable processing precision, diverse processing capabilities, and broad material adaptability. The processing abilities and applications of the ultrafast laser still need more exploration. In the field of material processing, controlling the atomic scale structure in nanomaterials is challenging. Complex effects exist in ultrafast laser surface/interface processing, making it difficult to modulate the nanostructure and properties of the surface/interface as required. In the ultrafast laser fabrication of micro functional devices, the processing ability needs to be improved. Here, we review the research progress of ultrafast laser micro/nano fabrication in the areas of material processing, surface/interface controlling, and micro functional devices fabrication. Several useful ultrafast laser processing methods and applications in these areas are introduced. With various processing effects and abilities, the ultrafast laser processing technology has demonstrated application values in multiple fields from science to industry.

Surfaces with micro-nanoscale structures show different optical responses, including infrared reflection, thermal radiation, and protective coloration. Direct realization of structure camouflage is important for material functionalities. However, external cloaks or coatings are necessary in structure camouflage, which limits the surface functionality. Here, we propose a novel strategy for the direct structure camouflage through topography inherited removal (TIR) with ultrafast laser, featuring pristine topography preservation and scattering surface fabrication. After multistep TIR, pristine topographies are partially and uniformly removed to preserve the original designed structures. Optical response changes show the suppression of specular reflection by uniformizing reflected light intensity to a low level on the inherited surface. We produce various structure camouflages on large scaled substrates, and demonstrate applications of information encryption in code extraction and word recognition through structure camouflage. The proposed strategy opens opportunities for infrared camouflage and other technologies, such as thermal management, device security, and information encryption.