In order to achieve intelligent real-time monitoring of weak currents, the magneto-optical crystal is used as the sensing element of fiber optic current sensor based on the Faraday effect with the advantages of the large Verde constant, high sensitivity, small size, easy integration and so on. The demodulation mechanism of a polarization fiber optic current sensor using magneto optical crystal is derived and analyzed with the Jones matrix. A polarization fiber optic current sensing system for measuring weak current using magneto-optical crystal is built. And a dual optical self balancing measurement method using the basis of polarization analysis technology is proposed to eliminate the unequal loss coefficients of the two optical paths, and the demodulation expression for polarization fiber optic current sensor in practical applications is obtained with a maximum sensitivity of 7.15×10-4rad/mA and a micro current measurement resolution better than 0.5mArms.

In response to the challenges faced by traditional microscopy systems, which require multiple imaging and the use of image stitching techniques when covering large-area pathological slices, a large-field zoom microscope optical system has been designed. By ingeniously combining a large-field microscope objective and a zoom tube lens, this system achieves a single imaging of pathological slices, thereby obtaining complete information about the slices. By adjusting the magnification of the zoom tube lens system, it is possible to observe suspected lesion tissues in detail. The large-field microscope objective and the zoom tube lens were optimized using ZEMAX optical software. The design results show that the combined system has a focal length range of 90~800mm, achieving a 12x zoom, a working distance of 100mm, and a resolution of up to 3.45m. Across the entire field of view, the Modulation Transfer Function (MTF) is greater than 0.3 at 75lp/mm, approaching the diffraction limit, indicating high resolution. An experimental system was set up to test the imaging performance of the large-field microscope objective, and the results demonstrated excellent lens quality, with a maximum object field of view reaching 18mm×18mm. This enabled the observation of large samples from details to the overall picture, significantly improving the detection efficiency.

A kind of training system of dimming, zooming and focusing of optical measurement equipment is presented. Firstly, the principle and mode of dimming, zooming, focusing and the training requirements are analyzed. Then, the training system is designed, which consists of an objective lens group, a dimming module, a zooming module, a focusing module, a color camera, a mechanical structure, the lens control module and a teaching and training operation software. Based on the task requirements for dimming, zooming and focusing, the training personnel calculate and analyze the number of pulses and the phase sequence required for step motor. Then, the corresponding software parameters and hardware connection are changed according to the pulse number and power-on phase sequence analyzed above. Through experimental phenomena and experimental data, the principles and laws of dimming, zooming and focusing are analyzed and summarized. Finally, the experiment of dimming, zooming and focusing subjects are carried out. The experiment shows that the system can meet the teaching and training requirements.

Compared to radio frequency communication, optical communication can maintain higher transmission rates and more reliable channel modes. However, there are also some issues with optical communication technology, such as line-of-sight issues, where optical communication cannot proceed normally when there are obstacles between the sending and receiving ends. A photoelectric integrated antenna has been designed to address the above issues, which can simultaneously perform millimeter wave communication and optical communication. When optical communication cannot function properly, the millimeter wave antenna can work, thus compensating for the line-of-sight defect in optical communication. The main material used in the design is K9 glass. By utilizing the different physical properties of K9 glass in different frequency bands, designing appropriate lens shapes and scaling the lenses, K9 glass can achieve different forms of communication work in the millimeter wave communication frequency band and optical communication frequency band. When K9 glass is used as a dielectric resonator, millimeter wave communication is achieved; When used as a lens, it can focus the light beam and achieve optical communication. The millimeter wave antenna is fed by a coplanar waveguide, and a patch type LED light source is placed below the center of the dielectric resonator through slotting technology. This optoelectronic integrated antenna integrates the optical wave communication system and the millimeter wave communication system on a single metal aluminum plate, enabling two types of communication simultaneously without interfering with each other. The simulation results show that the operating frequency of the millimeter wave antenna is between 32.5GHz and 33.4GHz, and the gain within the frequency band is stable. The peak gain of a single dielectric resonator can reach 5.4dBi. After adding the lens, the optical power at the receiving end is significantly increased, thereby improving the transmission rate of optical communication.

Learning the perception, cognition, and complex behavior mechanisms of neural networks through dynamic observation of large volume neurons in the brain is a fundamental issue in neuroscience. Light field microscopy, which allows for three-dimensional imaging at video frame rate, has become a technological choice for real-time observation of neural activity. An overview of the current imaging methods of light field microscopy is provided in this article, with a focus on new algorithms.Compared with traditional iterative reconstruction methods, using light field microscopy to image neuronal activity requires the development of new deep learning based algorithms that fully utilize the prior embedded in physical and optical models, integrate model driven and data driven algorithms, enhance the interpretability and generalization ability of algorithms, and achieve fast and robust light field microscopy imaging.

To reduce signal crosstalk and bending loss in few-mode fibers while increasing the effective mode field area, a few-mode fiber with a ring core and lateral hole auxiliary structure was designed. Theoretical analysis of the effective refractive index distribution, bending loss, and effective mode field area of this fiber was conducted. Using the finite element method, the impact of fiber parameters on the minimum effective refractive index difference between adjacent LP modes, mode field area, and bending loss was calculated. The minimum effective refractive index difference between modes can reach 1.7×10-3, and the mode field area for all modes is greater than 106m2. When the bending radius is 28mm, the maximum bending loss for each mode is only 10-11dB/m. This structure features a large mode field area, low inter-mode crosstalk, and better bending resistance, extending the research ideas for space-division multiplexing.

The optical properties of monocrystalline silicon are crucial for the performance of short- and medium-wave infrared detection systems, and they significantly impact the advancement of aerospace technology. The thermal stress problem caused by temperature gradient in preparing monocrystalline silicon by the Czochralski method is focused on in this paper, and the influence of thermal stress on the optical inhomogeneity of monocrystalline silicon is examined. By comparing the stress birefringence phenomenon of monocrystalline silicon under three different methods of no thermal annealing, slow thermal annealing, and rapid thermal annealing, the infrared absorption and refractive index characteristics of monocrystalline silicon in the near-infrared band (3~5m) are deeply analyzed. The influence of different annealing methods on the optical inhomogeneity of monocrystalline silicon is summarized. Herein, the elucidation of the stress-induced effects on optical uniformity is reported and present a strategy aimed at enhancing optical uniformity is presented through stress reduction in the monocrystalline silicon. This work lays the theoretical groundwork and offers practical insights for the fabrication of high-quality monocrystalline silicon.

There are many coupling loss factors between optical devices and input/output fibers, mainly including temperature, stress, mode field mismatch, etc., which cause additional losses. The Multimode Star Coupler (MSC) module in the optical control converter valve of the power system is considered as an example with simplified quantitative analysis, it is found that the influence of thermal expansion on the coupling loss between the fiber array and the waveguide array can be ignored. Based on waveguide theory and mode coupling theory, the influence of input and output waveguide structure of MSC module on coupling performance was analyzed using numerical calculation methods-the mode field area and mode mismatch between waveguide and fiber caused significant coupling losses. Therefore, an inverted taper structure, transforming the mode field size and reducing the mode mismatch between the waveguide and the fiber, is optimized to minimize the coupling loss between the waveguide and the fiber.

In order to improve the efficiency of laser surgery and reduce the damage to surrounding healthy tissues during laser surgery, the influence of the peak power of pulsed holmium laser and continuous thulium laser power on the thermal effect of soft tissues was explored. Build an in vitro model device to find the optimal parameters for laser ablation of tissue, the pulsed holmium laser power is 20W, 40W, 60W, 80W, the pulse duration is 200s and 800s, and the pulse energy is 1J, 2J, 4J. The continuous thulium laser power is 20W, 40W, 60W, 80W, 100W, 110W. Finally, the in vitro model was placed in physiological saline and kept at a constant room temperature for experiments. The damaged tissue after laser ablation was sliced and stained, and pathological slices were analyzed. The peak pulse power has a great influence on the ablation zone of soft tissue. The ablation depth of the laser combination with the pulse energy of 4J×10Hz is 111.82% higher than that of the laser combination with the pulse energy of 1J×40Hz, while the effect on the solidification zone is only 9.96%. Pulse duration had little effect on soft tissue, and ablation depth was increased by 18.49% with shorter pulse width. The ablation depth of tissue increases with the increase of the power of continuous thulium laser, and the ablation efficiency is correspondingly increased, and the hot solidification zone is almost unaffected. The ablation efficiency of 100W is nearly 88.26% higher than that of 20W.

Super multi-view (SMV) three-dimensional (3D) display can offer immersive 3D viewing effects, but the rendering and synthesis process of massive viewpoint images poses significant challenges to real-time performance. In this paper, a real-time rendering method of backward ray tracing in SMV display is proposed. According to viewpoint allocation matrices and sub-pixel physical coordinates, rays are traced backward from viewpoint positions to 3D scenes, enabling real-time rendering directly on the synthetic image at the sub-pixel level. The results indicate that while maintaining consistent display quality, the rendering frame rate remains above 35 FPS even with an increasing number of viewpoints. The proposed method avoids information redundancy in the rendering synthesis process, achieving a rendering speed improvement of 5 orders of magnitude compared to traditional sequential viewpoint rendering methods. Thus, it provides a promising avenue for achieving super multi-view dynamic 3D display.

Distributed interferometric antenna arrays leverage simultaneous multi-antenna receptions to enhance detection sensitivity. Before phase-coherent signal combination for Signal-to-Noise Ratio (SNR) improvement, it is essential to accurately detect and compensate for time and frequency differences among the signals. The accuracy of frequency difference estimation at the receivers is inherently limited by the spectral leakage and grating lobe artifacts of the Fourier transform. This work proposes a method for optimizing the window function length in frequency difference estimation, reducing the Root Mean Square Error (RMSE) from 1kHz to under 30Hz in low SNR conditions. The algorithm's validity and superiority are demonstrated through the coherent combination of four signals, achieving an SNR improvement of 5.79dB (close to the theoretical gain of 6dB).

Point target recognition technology based on optical images is widely used in space science, military security, automatic driving and other fields. Since the small targets in long-distance behave as point targets when being detected, the existing recognition algorithms based on spatial information such as target shape and contour will have difficulties. In order to address the problem of point target recognition, this article carries out the research of point target recognition technology based on motion features. The physical characteristic quantities of the temporal variation information of target intensity are extracted to reflect the motion state of the target. Combining with the wavelet analysis denoising to improve the accuracy of the statistical feature extraction, The recognition of point targets of different motion states is realized by using the machine learning method. This article builds an experimental system for point target recognition verification. The experimental results show that this method can realize high accuracy point target recognition based on small sample learning. The recognition accuracy based on all the extracted features and several key features is 87.8% and 84.5%, respectively, which verifies the validity of the point target recognition technology proposed in this article.

In the mid- and far-infrared wavelength bands, it is relatively difficult to measure the homogeneity of materials because infrared materials are unable to transmit visible light; however, in recent years, the demand for the processing accuracy of infrared materials has become increasingly high, and thus the realization of an accurate measurement of the homogeneity of infrared materials is imminent.Among the current detection means, interferometry is widely used as a non-contact and high-precision detection means. The non-uniformity of infrared materials was measured, and a mid-infrared interferometer with a wavelength of 3390nm was used for the experiments. The precision and accuracy of the present interferometer are verified by measuring the same element by transmission method and verifying the results by flip-flop method. Meanwhile, a comparison experiment was carried out between the present interferometer and the Zygo interferometer on the element made of fused silica, and the results showed that the measurement accuracy of the present interferometer can meet the requirements. This study provides an important reference for the accurate measurement of non-uniformity of infrared materials, which has certain theoretical and practical significance.

In recent years, the management of dental caries has significantly shifted towards early detection and prevention, greatly enhancing treatment outcomes and reducing the need for invasive procedures. The article investigates the feasibility of using near-infrared diffuse reflectance imaging for early caries detection. The feasibility of using near-infrared diffuse reflectance imaging for early caries detection is investigated. Based on the theory of diffuse reflectance imaging in tissue optics and building upon previous research, we developed a near-infrared diffuse reflectance imaging system using 780nm wavelength LED illumination, named NIRCaries 780.To confirm the performance of NIRCaries 780,54 tooth surfaces were examined using both NIRCaries 780 and DIAGNOcam. Caries lesions were assessed by experienced dentists according to the ICDAS Ⅱ criteria. The performance of NIRCaries 780 was evaluated using the Spearman rank correlation coefficient. Compared to the ICDAS Ⅱ standard, the sensitivity, specificity, and accuracy of NIRCaries 780 were 0.806, 0.870, and 0.833, respectively. The sensitivity, specificity, and accuracy of DIAGNOcam were 0.871, 0.913, and 0.889, respectively. This technique, compared to DIAGNOcam, is simple to use, non-contact, and feasible for indicating early enamel caries. Future research will combine near-infrared diffuse reflectance imaging with automatic classification algorithms to provide technical means for home oral health care and caries prevention.

OFDR is prone to phase noise during long distance and large strain sensing, which makes the strain sensing accuracy poor or unable to restore the real strain change. The cross correlation spectrum moving average method is used to process the original cross correlation spectrum of OFDR to improve the accuracy of strain sensing. The mechanism of strain demodulation interference noise generation is described, and the principle of OFDR strain sensing accuracy improvement based on cross-correlation spectrum moving average is analyzed. The OFDR strain sensing system is built, and experimental verification is carried out on 103.8m sensing fiber. The experimental results show that when the sweep frequency range is 60nm and the average sliding block size is 1×10, the strain sensing with a spatial resolution of 1.33cm and a maximum value of 4000 can be achieved in the 103.8m fiber under test, and the standard deviation of wavelength offset in the strain region is significantly reduced. It is proved that the cross-correlation spectrum moving average method can effectively improve the strain demodulation precision of OFDR system.

In order to improve the anti-interference performance of sea surface target detection, based on polarization filtering technology, a polarization characteristic estimation and suppression method of sea surface flare was designed, and a polarization two-way reflection distribution model was established based on the GGX model, and different wind speeds and different detection azimuth differences were simulated and analyzed. The results show that there is no significant change in flare characteristics at different wind speeds. The detection azimuth difference is 180° in the main reflective surface, the flare phenomenon is obvious, and the polarization angle is in the range of 90~95°. Finally, the method in this paper is applied to a certain type of optoelectronic equipment, and the sea surface verification test is carried out for the practical application scenario in a sea area of Dalian. The experimental results show that the flare suppression effect is the best when the polarization angle is 90°, the contrast of the best image is increased by 21.26% on average, and the proportion of saturated pixels is reduced by 84.48% on average. Compared with the detection results of traditional optoelectronic equipment, the polarization method can effectively suppress the sea surface flare interference and improve the detection performance of the target under the sea surface flare interference.

Due to significant difference in precision of indoor visible light positioning caused by non-uniform light intensity distribution of the LED, a light intensity RSS fingerprint analysis based indoor visible light positioning method combined with sequence to sequence model. The light intensity RSS fingerprint vectors are set as input sequence, the three dimensional coordinates are set as output sequence, the sequence to sequence model is used to learn the non-liner mapping relationship between the RSS fingerprints and the indoor three dimensional coordinates. The self-attention mechanism is introduced to sequence to sequence model, the self-attention mechanism is used to analyze the discrimination of each element in the light intensity RSS fingerprint for different position, in the prediction phase, the importance of each RSS element is adjusted. Simulation results show that the proposed method reduces the average visible light positioning error under different signal to noise ratio conditions.

Aiming at the problems of long computation time and low reconstruction accuracy that exist when the laser absorption spectroscopy technique acquires the initial CO2 signal for concentration field reconstruction under the condition of non-uniformly distributed flue, a CO2 concentration field reconstruction method based on the super-resolution algorithm is proposed, and the EO algorithm is optimized and improved. The improved EO algorithm significantly improves the iteration speed and search accuracy in the calculation of CO2 concentration distribution; in the super-resolution temperature field reconstruction algorithm, an input compensation mechanism is added and the dense connection network is optimized. After experimental comparison, the improved CO2 concentration reconstruction algorithm effectively improves the reconstruction accuracy, and the average ARE and RMSE values reach 0.053733 and 0.054, respectively.

In the manufacturing industry, the flatness error of some components has reached the order of tens of micrometers, exceeding the measurement range of traditional interferometers. To solve this problem, a large angle grazing incidence interferometry measurement method can be used, such as the prism method with variable inclination angle and small gap phase shift interferometry. To solve the problem of high surface reflectivity under large angle grazing incidence, which forms multi beam interference and increases the difficulty of phase extraction, two methods are proposed: reducing multi beam interference through reflectivity control film system and eliminating multi beam interference through dynamic film system. By analyzing the system using admittance matrix and simulating the incident angle of 83 ° using Matlab, when the reflectivity of the right angled prism chord is controlled at 10%, the error in phase shift calculation caused by multi beam interference will be reduced to around 7.2nm. Finally, the dynamic film design and actual equipment that can completely eliminate multi beam interference were introduced.