Hongyi Lin

Fluorescence microscopy is renowned for its high sensitivity and specificity, making it a vital tool in biomedical research. However, during practical imaging, defocused background signals often introduce strong interference, significantly reducing image contrast and consequently affecting subsequent structural analysis and quantitative assessments. Traditional computational methods for suppressing defocused background, such as deconvolution or filtering algorithms, typically rely on probabilistic models or the assumption that “defocused background is low-frequency signal.” These approaches are prone to noise amplification or loss of valid signals in complex imaging scenarios, compromising processing accuracy and reliability. To address the defocused background interference in fluorescence imaging, we propose a physics-guided training-free neural network for effective background suppression. This method incorporates the forward physical process of fluorescence imaging into the network architecture design, utilizing an optical propagation model as a physical constraint to guide the network's self-adaptive optimization without the need for annotated data. Requiring only a single fluorescence image for network parameter updates, our approach significantly reduces dependency on paired training data and overcomes the bottleneck of data acquisition in supervised learning. Experimental results demonstrate outstanding background suppression capability of the proposed method on both spoke-like sample and real biological tissue images, achieving a contrast improvement of up to approximately 5.5 times. This method establishes a novel imaging paradigm for background removal with neural networks, offering an effective solution to background interference in fluorescence imaging.

Compact mid-infrared laser generation is achieved using a demonstrated shared-cavity optical parametric oscillator (OPO) based on periodically poled magnesium-doped lithium niobate (PPMgLN). The shared-cavity design co-resonates the 1064 nm fundamental light and the ~1.5 μm signal wave within a single optical cavity, thereby ensuring good spatial mode overlap and intracavity power enhancement. This configuration substantially lowers the oscillation threshold and enhances the overall conversion efficiency. The oscillation threshold at 807.6 nm is only 0.9 W. Under stable operation at a 5.0 W pump power, the system generates output at 1472.9 nm (signal) and 3833.2 nm (idler), with respective output powers of 430 mW and 187 mW. Signal linewidth is 0.9 nm, while the idler linewidth is relatively wide, 6.4 nm. The generated 3.8 μm mid-infrared laser falls within the molecular “fingerprint” region – making it highly valuable for high-sensitivity spectral analysis and trace-gas sensing – while the 1.5 μm signal wavelength lies within the low-loss telecommunications window.

Immersive glasses-free display technologies provide stereoscopic visual experience for multiple users without the requirement of specialized glasses. By accurately customizing light fields, stereoscopic display can replicate realistic three-dimensional scenes with motion parallax and depth cues. The amalgamation of stereoscopic display technologies, computing techniques, exhibition design, information and communications technologies (ICTs) are widely used in conference and exhibition centers, museums, libraries, art galleries, archive centers, and so forth. These innovative models of modern exhibition industry reshape the organizational structure, improve working methods and business processes for upstream and downstream enterprises. Immersive glasses-free stereoscopic display technologies consist of holographic 3D display, optical illusion display, projection stereoscopic display, floating 3D display, and light field 3D display. This paper analyzed the aforementioned technical background, technical principles, and typical application scenarios. Then, the advantages and disadvantages of each technology in key performance indicators, including resolution, color reproduction degree, and field of view angle were compared. Also, the future trends, limitations and potential improvement directions in practical application were discussed. This study explores the application of immersive glasses-free stereoscopic display technologies in meetings, incentives, conventions, and exhibitions (MICE) to improve audiences’ immersive experience, providing practical insights into such technologies as a critical basis for sustainable exhibition service.

Off-axis aberrations degrade peripheral retinal image quality, yet the aberrations introduced by the spectacle lens itself are controllable. This study proposes a new, to the best of our knowledge, microlens array design inspired by moiré superlattices to reduce induced astigmatism and improve peripheral image quality while maintaining therapeutic myopic defocus. Combined with the Atchison eye model, simulations demonstrate that, compared to defocus incorporated multiple segments (DIMS) lenses, our design reduces the maximum vectorial astigmatism (C ^′ ) from −5.63 to −4.42D under static conditions. During 15° eye rotation, the MTFA value of the Type-III lens at the 20 cy/mm spatial frequency is elevated by 0.155 compared to the DIMS lens, while at 25° rotation, central C ^′ is optimized from −3.77 to −2.52D.

Terahertz (THz) waves, situated between the infrared and microwave regions, possess distinctive properties such as non-contact, high penetration, and high resolution. These properties render them highly advantageous for non-destructive thickness measurement of multilayer structural materials. In comparison with conventional ultrasound or X-ray techniques, THz thickness measurement has the capacity to acquire thickness data for multilayer structures without compromising the integrity of the specimen and is characterized by its environmental sustainability. The extant THz thickness measurement techniques principally encompass time-domain spectroscopy, frequency-domain spectroscopy, and model-based inversion and deep learning methods. A variety of methodologies have been demonstrated to possess complementary advantages in addressing subwavelength-scale thin layers, overlapping multilayer interfaces, and complex environmental interferences. These methodologies render them suitable for a range of measurement scenarios and precision requirements. A wide range of technologies related to this field have been applied in various disciplines, including aerospace thermal barrier coating inspection, semiconductor process monitoring, automotive coating quality assessment, and oil film thickness monitoring. The ongoing enhancement in system integration and continuous algorithm optimization has led to significant advancements in THz thickness measurement, propelling it towards high resolution, real-time performance, and intelligence. This development offers a wide range of engineering applications with considerable potential for future growth and innovation.

With the growing demands for visual effects and interactive experiences in the exhibition industry, fluorescent patterns have gained attention for their unique visual impact and interactivity. The development of high‐resolution, low‐energy fabrication technologies with superior visual effects is crucial for this field. However, traditional methods are hindered by low resolution, photobleaching of organic dyes, and poor environmental adaptability, limiting their application in the exhibitions. This study utilizes urea and citric acid as raw materials to synthesize green‐emitting carbon quantum dots (CQDs) via a hydrothermal method. After solution dispersion, a stable aqueous dispersion is coated onto a piece of white filter paper to form a uniform, dense fluorescent layer. Based on the fluorescence quenching mechanism induced by the laser thermal effect, a low‐power (hundred‐milliwatt level) continuous‐wave laser beam is employed to selectively irradiate the coating. The localized thermal energy triggers structural changes in the CQDs, leading to irreversible fluorescence quenching in the irradiated regions. By precisely controlling the laser spot size and scanning path, high‐resolution dark patterns are etched onto a green fluorescent background, achieving high‐contrast patterned fluorescence modulation. This technology presents an eco‐friendly and cost‐effective patterning solution for diverse fields, including exhibitions, artistic performance, anti‐counterfeiting packaging, and museum displays.