Featuring low threshold current, circular beam profile, and scalable fabrication, vertical cavity surface emitting lasers (VCSELs) have made indispensable contributions to the development of modern optoelectronic technologies. Manipulation of electromagnetic fields with emerging flat optical structures, namely metasurfaces, offers new opportunities to minimize complex optical systems into ultra-compact dimensions. Here, we proposed and experimentally demonstrated Vertical Cavity Metasurface-Emitting Lasers (VCMELs) through the monolithic integration of high-index metasurfaces, characterized by their remarkable spatial controllability over the laser beams. Such wafer-level monolithic integration of metasurfaces through VCSELs-compatible technology not only considerably simplifies the assembling process but also preserves the laser characteristics, with 2 great potential to promote various wide-field applications of VCSELs such as optical data communication, ultra-compact light detection and ranging (LiDAR), 3D sensing, and directional displays. Introduction: Vertical-cavity surface emitting lasers (VCSELs) have experienced a soaring development over the last 30 years, particularly after the demonstration of the first continuous-wave (cw) room-temperature device. 1-3 Their unique features such as low-power consumption, circular beam profile, wafer-level testing, large-scale two-dimensional (2D) array have made them the most versatile laser sources for a large number of applications ranging from optical communications, to instrumentation, as well as laser manufacturing and sensing. 4-6 The exploding application demands and the rapidly growing markets pose a longstanding challenge to further improve their performance while realizing precise beam control. In this context, the replacement of the top reflector with resonant structures and the incorporation of photonic crystal have been extensively employed to tune the emission, achieve high brightness,respectively. Meanwhile, considerable attention has been paid to improve the beam quality of the VCSELs, for example, by preventing high-order transverse modes 7-11 .Despite the fact that single-fundamental-mode laser can be realized by limiting the active region with a reduced oxide aperture, strong diffraction effect produces highly

Metal-organic frameworks (MOFs) have attracted much attention in the areas of biomedicine and medicine owing to their versatile porous structure. However, the oversize and high cellular toxicity of some metal-based MOF particles have hindered their development. Therefore, a series of small Ti-based MOFs are prepared with the introduction of tetraethyl orthosilicate (TEOS) into the reaction system. Compared with the Ti-based MOFs prepared by traditional methods, the size of the Ti-based MOFs prepared with this method is decreased by 42.78%. Meanwhile, the good biocompatibility of the prepared Ti-based MOF particles toward the L929 cell lines is proven using CCK-8 assays. Furthermore, the controlled release property of the Ti-based MOFs is evaluated by using ibuprofen (IBU) as a model drug. The amount of drug loaded in the samples is shown to be approximately 10%, and approximately 95% of the IBU is released from the MOFs after exposure to PBS for 24 h. We conclude that the size-decreased Ti-based MOFs prepared with the introduction of TEOS into the reaction systems are potential drug carriers in terms of their good biocompatibility and effective performance in the controlled release of a drug.

Metasurfaces offer complete control of optical wavefront at the subwavelength scale, advancing a new class of artificial planar optics, including lenses, waveplates, and holograms, with unprecedented merits over conventional optical components. In particular, the ultrathin, flat, and compact characteristics of metasurfaces facilitate their integration with semiconductor devices for the development of miniaturized and multifunctional optoelectronic systems. In this work, generation of structured light is implemented at an ultracompact wafer‐level through the monolithic integration of metasurface with standard vertical cavity surface‐emitting lasers (VCSELs). This work opens new perspectives for the design of structured light systems with compactness, lightweight, and scalability. Ultracompact beam structured laser chips with versatile functionalities are experimentally demonstrated, including multichannel beams array generation, on‐chip large‐angle beam steering up to 60°, and wafer‐level holographic beam shaping with a wide field of view (about 124°). The results will promote the development of compact light structuring systems with great potential in 3D imaging, displays, robotic vision, human–computer interaction, and augmented/virtual reality.

The analysis of vibration signals has been a very important technique for fault diagnosis and health management of rotating machinery. Classic fault diagnosis methods are mainly based on traditional signal features such as mean value, standard derivation, and kurtosis. Signals still contain abundant information which we did not fully take advantage of. In this paper, a new approach is proposed for rotating machinery fault diagnosis with feature extraction algorithm based on empirical mode decomposition (EMD) and convolutional neural network (CNN) techniques. The fundamental purpose of our newly proposed approach is to extract distinguishing features. Frequency spectrum of the signal obtained through fast Fourier transform process is trained in a designed CNN structure to extract compressed features with spatial information. To solve the nonstationary characteristic, we also apply EMD technique to the original vibration signals. EMD energy entropy is calculated using the first few intrinsic mode functions (IMFs) which contain more energy. With features extracted from both methods combined, classification models are trained for diagnosis. We carried out experiments with vibration data of 52 different categories under different machine conditions to test the validity of the approach, and the results indicate it is more accurate and reliable than previous approaches.

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