To reduce the noise interference and peak positioning error of the spectral system when the position of the object to be measured changes, based on the principle of Kalman filtering algorithm, a method is proposed to improve the measurement accuracy of the confocal system by taking the results of Voigt peak-finding and positioning as the observation error and making the optimal estimation. In this work, calibration experiments are carried out to determine the measurement range and accuracy of the spectral confocal system. Then, the denoising processing of spectral signals such as median filtering, Savitzky-Golay filtering, and fast Fourier transform filtering is compared in turn, and Gaussian, Lorentz, and Voigt fitting methods are used to find peaks. At the same time, the effects of peak extraction, Gaussian width, Lorentz width, and amplitude error on fitting accuracy in Voigt fitting are analyzed. The experimental results show that the measurement range of the system can reach 3 mm, and the radius of the central spot changes by nearly 1.79 times, The Kalman filtering algorithm can reduce the positioning error caused by noise in the system, and the system accuracy can be improved by 11 times to meet the requirements of high-precision measurement.

Metalens have gradually replaced or supplemented traditional refractive and diffraction lenses with their unique advantages, leading to further miniaturization of high-performance optical devices and systems. This miniaturization is expected to lead to compact nanoscale optical devices for applications in cameras, lighting, displays, and wearable optics. However, in conventional metalens designs, the Pancharatnam-Berry (PB) phase usually requires the chirality limitation of left and right circularly polarized light. In order to avoid the incident limitation of the linearly polarized light by the left-handed circular polarization (LCP) and right-handed circular polarization (RCP), an all-dielectric metalens based on PB phase was designed to achieve near-field focusing of linearly polarized light. It coincides with the main output wavelength (visible band) of the metasurface filter. The effects of various variables on the focusing properties of the light field were studied and verified by effective time-domain difference simulation in this paper. The unprecedented design freedom of metalens and other metasurface optical components will greatly expand the application fields of micro-optics and integrated optics.

Depth information plays an important role in the fields of robotics and autonomous driving. The depth map obtained by the depth sensor is relatively sparse. Researchers have proposed a large number of methods to complement the missing depth values. However, most of the existing methods aim at opaque objects. Based on the powerful representation ability of convolution neural network, this paper designed a dual-branch-guided encoder-decoder structure network. Through mask-guided branch for transparent objects, it improves the ability of the network to extract feature information of transparent objects. And spectral residual blocks improves the stability of network in training process and the ability to obtain object structure information. In addition, attention mechanism is added to improve the feature modeling ability of network space and semantic information. The network achieves state-of-the-art results on all two datasets.

It has become the research focus to realize the infrared radiation spectrum regulation by designing and optimizing micro/nano photonic structures. Recently, neural network inverse design has attracted wide attention because of its advantages such as high freedom, fast speed and good performance. Here, infrared radiation computation and inverse design of micro/nano photonic structures based on neural network is proposed. Specifically, for the multilayer dielectric thin film structure, a multilayer perceptron neural network model was established. The mapping relationship between the thickness of the multilayer thin film and its infrared radiation spectrum was built up through the training of sample data. The radiation spectrum computation and inverse design of the thin film structure by this network was realized. At the same time the designed film was applied to the field of radiative cooling. The results show that even at 3% solar radiation absorption and 6 W/(m2·K) non-radiation heat transfer coefficient, the thin film radiative cooler can still reduce the temperature to about 7 ℃ below the ambient temperature. The research results will have an important impact on infrared radiation and other applications.

A silicon photonic chip space coupling system is studied, which simplifies the coupling mode of integrated photonic chip with optical fiber array, Through the spatial optical system, the light in the band near 1550 nm is vertically coupled into the integrated photonic chip through the grating coupler, and the optical sensing is realized through the waveguide and microring resonator. The multi-mode optical fiber is used to collect the emerging energy and carry out the temperature sensing test. The experimental results show that the transmission lines of the through-end ring resonator with frree spectral range(FSR) of 0.85 nm and Q value of 16321 are obtained by wavelength detection. In temperature sensing tests, the sensitivity reached 127 pm/℃. The results show that there is only a difference between spatial optical coupling and optical fiber array optical coupling in insertion loss, and the coupling system can get better temperature sensing test results. Spatial optical coupling has the advantages of convenient replacement of sensor chip and easy to multi-channel testing.

The terahertz photoconductive antenna driven by femtosecond laser is a common terahertz source in terahertz time-domain spectroscopic system. Because of its omni-directional radiation mode, the main lobe of photoconductive antennas is small and its directivity is poor. The effective control of the wide-band terahertz beam is important to improve the emission efficiency of the photoconductive antennas. Using low-temperature growth gallium arsenide (LT-GaAs) as the substrate material of antenna, the electromagnetic distribution characteristics of terahertz wave radiated by the butterfly antenna are simulated by the electromagnetic software CST, and the effect of dielectric lens on terahertz wave radiated by a butterfly antenna is studied. The optimum expanding region thickness of lens is obtained by theoretical and numerical analysis. The simulation results show that with the increase of frequency, the butterfly antenna can obtain higher directivity with a thinner expanding region of the silicon lens.

With the rapid expansion of laser application fields, the laser with ultra-high peak power and ultra-narrow pulse width has gradually become one of the important research directions of the laser fields in the future. These laser with ultra-high electric field energy posed a challenge for high precision laser power measurement. And the traditional methods of laser power measurement, such as photoelectric method, pyroelectric method and calorimetry etc., have gradually revealed the disadvantages that they are not suitable for the abovementioned laser. Besides, these traditional methods are difficult to achieve real-time online measurement. In order to overcome these difficulties, a new method of laser power measurement is needed. Therefore, a method of light radiation pressure for laser power measurement is proposed by the organization represented by the National Institute of Standards and Technology. This method makes the laser incident on the mirror with high reflectivity, and the momentum of laser photon converts into light radiation pressure on the mirror, and the light radiation pressure can be measured by a variety of mechanical sensing modalities. It can not only achieve rapid and accurate measurement of laser power, but also have no influence on laser transmission. Besides real-time online laser power measurement is also possible. In this paper, the basic principle, the system, and the research status of laser power measurement using optical radiation pressure method at domestic and foreign were reviewed systematically. The future developments of this method were discussed in detail.

In this paper, we designed a photon-number-resolving single-photon detector based on an avalanche photodiode, which used a short-pulse gated signal combining with a capacitive balanced noise suppression scheme to achieve a single-channel high-performance detection of 100 MHz with a detection efficiency of 40.5%, and effectively resolved the number of incident photons with spatial beam splitting. In order to more completely describe the quantum characteristics of the detector, we introduced the quantum detector tomography technology, starting from the single-channel single-photon detector to the dual-channel photon-number-resolving detector, performed quantum tomography calibration, reconstructed its positive-operator-valued measure matrix and the corresponding Wigner function, and established the corresponding theoretical model. The results show that the dual-channel 100 MHz photon-number-resolving detector can achieve quantum detection.

Traditional surgical navigation systems require operators to switch their eyes between the display screen and the lesion area. In order to solve this problem, augmented reality surgical navigation has been applied. This paper designs an augmented reality navigation system for interventional surgery in order to solve the problem that the operator cannot directly observe the relative position of the patient's lesion and surgical instruments during interventional procedures.The Unity software is used as the development platform to design the virtual surgical path before surgery and to display the relative distance between the lesion area and the surgical instruments in real time intraoperatively. The accuracy of the navigation system was verified using skull and ladder table experiments, and the virtual display showed an error of about 3.3 mm. This study confirms the feasibility of augmented reality surgical navigation for preoperative planning and real-time intraoperative guidance in interventional procedures.

Raman spectroscopy can identify the spectral characteristic peaks of plastic products, but the operation process is complicated and the accuracy needs to be improved. Therefore, a classification algorithm for plastic products based on one-dimensional convolution neural network (1-D CNN) is proposed. Firstly, data sets of 40 kinds of plastic packaging samples using polyethylene, polypropylene, polyethylene terephthalate and polystyrene as raw materials were established. Then, four algorithm models including 1-D CNN, KNN, DT and SVM were designed for training, and the spectral classification process, model accuracy and robustness were compared. The experimental results show that the classification accuracy of 1-D CNN can reach 98.62% without pretreatment. And the accuracy rate is 96.42% under 60 dB noise, which is better than the three traditional machine learning algorithm models. The results show that the multi-classification method of Raman spectral fusion neural network can improve the detection performance of plastic products.

Due to high conductivity and large specific surface area, 2D titanium carbide (Ti3C2Tx) can be used as an electrode material for supercapacitors with high energy density. However, the deactivation of Ti3C2Tx through irreversible oxidation in energy storage and the poor surface interaction between Ti3C2Tx and substrates result in poor cycle stabilities of Ti3C2Tx supercapacitors, thereby greatly hindering wide applications of energy storage materials. In this paper, Ti3C2Tx is used as an active layer and covered by a graphene oxide (GO) film. The GO film weakens the oxidation deactivation of Ti3C2Tx. Meanwhile, a heat treatment procedure of the electrode is involved to improve the surface interaction. This makes the cycling stability of the Ti3C2Tx/GO composite electrodes significantly improved, and the capacitance is higher than the initial one after 5000 cycles. The results can provide an innovative pathway for the design and preparation of high cycle-stability supercapacitors.