Abstract:Coherent Raman spectroscopy and imaging technology， as a new type of label-free detection technology， has been widely used in biomedicine， material science and other fields by virtue of its high specificity and non-invasive advantages. In recent years， the combination of time stretching and coherent Raman spectroscopy effectively breaks through the limitations of traditional spectrometers in terms of sampling rate and spectral range， and provides a new idea for high-speed and broadband Raman spectroscopy and imaging. This paper firstly describes the basic principle of time stretching and its theory， and summarizes the results of the application of this technology in other fields； then systematically combs through the research progress of coherent Raman spectroscopy based on time stretching； finally， it looks forward to the future development of coherent Raman spectroscopy based on time stretching.

Abstract:The GF-7 satellite is equipped with China "s first operational earth observation laser altimeter and sub-meter optical stereo camera. High-precision laser altimetry data and sub-meter-level optical imagery data enable 1：10，000-scale stereoscopic mapping without ground control points， offering unique application advantages in large-scale spatial infrastructure construction for digital twin water resources management and water level monitoring of lakes and reservoirs. In the study， Miyun Reservoir is taken as the main research area. The GF-7 laser altimetry data and stereo image are used to extract the reservoir water level and the surrounding digital surface model（DSM）， and the application practice analysis is carried out. The results show that the absolute error of reservoir water level extracted based on laser altimetry data is less than 0.15 m， which is equivalent to the accuracy of the same type of foreign data. Based on the digital surface model， the water surface range prediction result F₁ is higher than 0.85， and the water volume change monitoring error is less than 3%， which can meet the requirements of related hydrological analysis applications. The relevant conclusions are of reference value for promoting the application of domestic GF-7 satellite laser altimetry and stereo image data in water conservancy， and better assisting the construction of basin level digital twin water conservancy.

Abstract:Coherent Raman scattering microscopy is widely regarded as a powerful tool for solving biomedical problems due to its chemical specificity， label-free imaging capability， high spectral resolution and high sensitivity. However， the clinical application of coherent Raman scattering imaging technology has long been hindered by environmental sensitivity and large volume solid-state lasers. Ultrafast fiber lasers， with their compactness and stability， can effectively overcome these shortcomings. In this paper， different realization methods and research progress of fiber-based laser sources in coherent Raman scattering imaging are reviewed， including supercontinuum fiber source， soliton self-frequency shift fiber source， fiber optical parametric oscillator and synchronized fiber source， and the future development is prospected.

Abstract:This paper presents a high-speed and robust dual-band infrared thermal camera based on an ARM CPU. It is composed of a low-resolution long-wavelength infrared detector， a digital temperature and humidity sensor， and a CMOS sensor. In view of the phenomenon of large contrast between face and background in thermal infrared image， this paper we search for a suitable accuracy-latency tradeoff for thermal face detection and propose a tiny-lightweight detector named YOLO-Fastest-IR. Four different scale YOLO-Fastest-IR0 to IR3 thermal infrared face detectors based on YOLO-Fastest are designed. To train and test four tiny-lightweight models， a multi-user low-resolution thermal face database （RGBT-MLTF） is collected， and the four networks are trained. Experiments reveal that the lightweight convolutional neural network can also perform well in the thermal infrared face detection task. And the algorithm is superior to the existing face detection algorithms in positioning accuracy and speed， which is more suitable for deployment in mobile platforms or embedded devices. After obtaining the region of interest in the infrared image （IR）， the RGB camera is guided by the results of thermal infrared face detection， to realize the fine positioning of RGB face. The experimental results show that YOLO-Fastest-IR has a frame rate of 92.9 FPS on a Raspberry Pi 4B and can successfully locate 97.4% of the face in the RGBT-MLTF test set. The integration of infrared temperature measurement system with low cost， strong robustness and high real-time performance was ultimately achieved， the temperature measurement accuracy can reach 0.3 degrees Celsius.

Abstract:NIR-II fluorescence imaging demonstrates significant advantages in biological imaging with its high signal-to-background ratio (SBR) and deep tissue penetration, showing broad application prospects in biomedical fields. The classification of NIR-II imaging windows facilitates the optimization of imaging processes. Among these, the 1400-1500 nm imaging window benefits from its unique water absorption characteristics, enabling effective suppression of scattering background and achieving high-contrast imaging. This study systematically evaluates the imaging potential of the 1400-1500 nm window through simulation studies and in vivo experiments. To advance the clinical translation of fluorescence imaging in the 1400-1500 nm window, indocyanine green (ICG), an organic small-molecule dye approved by the U.S. Food and Drug Administration (FDA), was employed as the fluorescent probe. Utilizing its extended fluorescence emission tail in the NIR-II region, high-contrast and high-resolution imaging of mouse vasculature and intestinal structures was achieved in the 1400-1500 nm window. Furthermore, in combination with methylene blue (MB), another FDA-approved agent, high-quality dual-channel NIR-II imaging was successfully implemented enabling precise localization of blood vessels and lymph nodes in mice. This research further explores the unique advantages of the 1400-1500 nm imaging window in biological imaging and its clinical application potential. It also provides valuable references for the clinical translation of NIR-II fluorescence imaging.

Abstract:Enamel demineralization often occurs in the early stage of dental caries. Studying the microscopic mechanism of enamel demineralization is essential to prevent and treat dental caries. Terahertz （THz） technology， especially continuous wave （CW） THz near-field scanning microscopy （THz-SNOM） with its nanoscale resolution， can be promising in biomedical imaging. In addition， compared with traditional THz time-domain spectroscopy （TDS）， portable solid-state source as the emission has higher power and SNR， lower cost， and can obtain more precise imaging. In this study， we employ CW THz-SNOM to further break the resolution limitations of conventional THz imaging techniques and successfully achieve the near-field imaging of demineralized enamel at the nanoscale. We keenly observe that the near-field signal of the enamel significantly lowers as demineralization deepens， mainly due to the decrease in permittivity. This new approach offers valuable insights into the microscopic processes of enamel demineralization， laying the foundation for further research and treatment.

Abstract:As a valuable Chinese herbal medicine, Panax notoginseng exhibits therapeutic efficacy and quality closely associated with its saponin content, which demonstrates significant geographical variations. To accurately authenticate the geographical origin and ensure medicinal quality, a novel method integrating terahertz precision spectroscopy with a convolutional neural network (CNN) algorithm was proposed. 40 Panax notoginseng samples from 4 regions in Yunnan Province, China—Honghe Autonomous Prefecture, Kunming, Qujing, and Wenshan Autonomous Prefecture—were analyzed using terahertz spectroscopy and high-performance liquid chromatography (HPLC). A CNN model was constructed and trained based on the acquired spectral and chromatographic data to classify the geographical origins. Experimental results revealed that the terahertz spectroscopy combined with the CNN model achieved a classification accuracy of 92.5%, significantly outperforming the 82.5% accuracy attained by the HPLC-CNN model. This finding highlights the potential of terahertz spectroscopy in component analysis and geographical traceability of herbal medicines, providing a novel scientific approach for rapid, non-destructive, and precise identification of Chinese medicinal materials.

Abstract:This study used a terahertz metamaterial sensor for the rapid and accurate detection of the antithrombotic drug Plavix， addressing the increasing demand for efficiency and sensitivity in drug content monitoring. Utilizing the terahertz vibration characteristics of Plavix， characteristic absorption peaks within the 1~3 THz band were identified. Based on these findings， a dual-polarization resonance metamaterial sensor was designed to simultaneously enhance the sensing signals of these characteristic absorption peaks. Experimental results indicate that the sensor attains a high level of fit （R²>0.97） for quantitative analysis in the quantitative detection of Plavix through the established two-indicator decision model. Consequently， the terahertz metamaterial sensing technology presented in this study exhibits superior performance in monitoring Plavix content and offers a new tool for clinical drug monitoring and broader biochemical sample analysis.

Abstract:Ischemia is a significant factor affecting the repair of peripheral nerve injuries， while exosomes have been shown to promote angiogenesis. To further investigate the detailed processes and efficacy of exosome therapy for ischemic peripheral nerve injuries， this study utilized glucose-modified near-infrared-II （NIR-II） quantum dots （QDs） to label adipose-derived stem cell exosomes （QDs-ADSC-Exos）， enabling long-term in vivo NIR-II imaging of exosome treatment for ischemic peripheral nerve damage. Experimental results confirmed that QDs can be used for non-invasive in vitro labeling of exosomes， with QDs-ADSC-Exos exhibiting strong fluorescence signals in the NIR-II window and demonstrating favorable NIR-II imaging characteristics in vivo. Notably， QDs-ADSC-Exos showed accumulation at the site of nerve injury in cases of ischemic peripheral nerve damage. Functional neurological assessments indicated that QDs-ADSC-Exos effectively promoted neural regeneration. This study highlights the potential of exosomes in treating ischemic peripheral nerve injuries and elucidates the spatiotemporal characteristics of exosome therapy， providing objective evidence for the further optimization of exosome-based treatment protocols.

Abstract:An overview is provided of the research progress in the application of hyperspectral detection technology for non-destructive testing of key parameters in tobacco leaf quality. Methods and equipment for the rapid detection of chemical components such as total sugar， reducing sugar， total nitrogen， nicotine， starch， chloride， and potassium in tobacco leaves using this technology are explored. The impact of different tobacco sample forms on spectral data is pointed out. The advantages and challenges of hyperspectral technology in applications such as field management， harvest optimization， and online grading in tobacco production are analyzed. The promising prospects of combining hyperspectral technology with artificial intelligence to build predictive models for tobacco leaf chemical composition are proposed. This combination provides scientific evidence and references for improving detection efficiency and quality in the tobacco industry.