The waveguide-type evanescent wave sensor depends on the interaction between the analyte and the evanescent field, and its detectability is determined by the intensity of evanescent wave. However, the intensity of evanescent waves in waveguides is relatively low compared to the amount of light that propagating in the waveguide core. As a result, the sensitivity of sensors is greatly limited. In this paper, we propose a waveguide probe based on hydrogel polymer to overcome this issue. The three-dimensional network structure of the hydrogel facilitates the penetration of the analyte into the waveguide, allowing the transmitted light localized inside the waveguide to be used for detection. This significantly improves the utilization efficiency of the transmission light. In addition, the experiment successfully suppressed the additional optical losses caused by water-induced swelling deformation of the hydrogel waveguide by adding other polymer monomers. Since the waveguide prepared from pure hydrogel causes deformation upon water absorption and swelling, which brings additional light loss, other polymers in addition to hydrogel are doped to maintain the basic shape of the waveguide. The experiment results show that the hydrogel polymer waveguide sensor has an absorption detection limit of is 1.0×10-9 g/mL for rhodamine B aqueous solution and 1.0×10-19 g/mL for fluorescence, which is about 7 orders of magnitude higher than that of other waveguide-based evanescent wave sensors. The hydrogel polymer waveguide sensor has the advantages of simple preparation, low cost, high adaptability and excellent sensitivity making it a promising candidate for various, applications, such as medical treatment and environmental monitoring.

A high-resolution and wide-spectral Raman spectrometer based on a Czerny-Turner (C-T) optical configuration with a rotating grating was designed to address the trade-off between resolution and spectral coverage in grating spectrometers. The excitation wavelength was set at 532 nm, with a spectral range of 80～3000 $ {\mathrm{c}\mathrm{m}}^{-1} $ with a resolution of 1.2 $ {\mathrm{c}\mathrm{m}}^{-1} $ The spectral range was divided into three bands: low (80～1450 $ {\mathrm{c}\mathrm{m}}^{-1} $), medium (855～2225 $ {\mathrm{c}\mathrm{m}}^{-1} $), and high (1630～3000 $ {\mathrm{c}\mathrm{m}}^{-1} $). Optimization was primarily focused on the medium band, while considering the entire frequency band. By fine-tuning the rotation angle of the grating, the low, medium, and high bands were all located on the effective image plane of the CCD detector. The point spread function, root-mean-square (RMS) wavefront error, and modulation transfer function (MTF) of the imaging system all met the design requirements.

Aiming at the problem that people with different diopters cannot freely change lenses when using wearable near-eye eye-tracking devices, this paper developed a set of plug-in near-eye eye-tracking system equipment. The system is composed of two parts: a near-eye acquisition hardware platform and an eye movement feature extraction algorithm. The hardware platform is an image acquisition module designed according to the structure of the optometry trial frame. The eye movement feature extraction algorithm is to train the eye detector and eye feature point detector based on machine learning, and then combines the candidate pupil fitting screening strategy to obtain the pupil diameter, center point, and blink frequency. The experimental results show that in this system algorithm, the correct rate of pupil detection is 97.24%, and the correct rate of blink detection is 91.59%. The device can meet the needs of eye-tracking detection and research for people with ametropia, and provide accurate and reliable eye-movement data.

In recent years, the world’s shortage of 3He resources has led to the high cost of 3He neutron detectors. The boron-based neutron detectors using boron carbide films as neutron conversion layers have gradually become the most promising alternative. In this paper, we prepared Ti/B4C multilayers using direct current magnetron sputtering method. The structure and composition of the films were characterized by transmission electron microscopy (TEM), time-of-flight secondary ion mass spectrometry (ToF-SIMS), X-ray photoelectron spectroscopy (XPS). The results show that there is crystallization in the Ti layer. H, O, N are the main impurities in the films, and are mainly distributed in the Ti layer and B4C-on-Ti transition layer. Higher base pressure can reduce the impurity content and increase the proportion of B content in the boron carbide films, thus improving the neutron conversion efficiency of the films. The results of neutron detection efficiency test prove that the high base pressure can effectively improve the efficiency of boron carbide neutron conversion layers.

Based on the silicon dioxide planar waveguide platform, a low power thermo-optical switch with multi-mode interference Mach-Zender is designed and fabricated. This device combines the stability of multi-mode interference coupler with the advantages of silicon dioxide waveguide and thermo-optical switch. The device parameters are optimized by simulation and the influence of the distance between the metal layer and the waveguide on the transmitted light intensity and power consumption is discussed. The test results show that the device has stable structure, small polarization dependence, insertion loss less than 2 dB. It can realize switch conversion. The power consumption is about 450 mW. The switching response time is 103 μs and 113 μs. The extinction ratio is more than 16 dB at 1 564 nm wavelength, and the size is 2.3 cm×0.25 mm. The device is not only compatible with CMOS technology, but also has good compatibility with optical fiber. Due to the advantages of low cost, large output and stable performance, the silicon dioxide waveguide optical switching devices provide a solid foundation for the development of optical communication and optical computing in the future.

Laguerre-Gaussian (LG) beams possess radial quantum number p in addition to orbital angular momentum (OAM) dimension, and thus LG beams can provide more physical degrees of freedom for applications such as optical communication and optical computing. However, the recognition accuracy of the LG beam pattern detection method, which is commonly used by interference and diffraction mechanisms, is significantly reduced when it is disturbed by atmospheric turbulence (AT), which limits its practical application. We propose a diffraction neural network (DNN)-based LG beam recognition method that achieves p in the range of 1-3. Even in the case of strong turbulence intensity and diffraction distance of 5 m, the recognition accuracy still reaches more than 95%. This DNN method can provide an effective way to accurately identify LG beam patterns, and has potential applications in high-capacity OAM communication and high-dimensional quantum information processing.

Through manganese doping, the luminescence wavelength of perovskite can be adjusted to improve its quantum yield. In this paper, Mn2+ doping was lead into two-dimensional perovskite (PMA)2PbBr4 and the luminescence properties and energy transfer mechanism in Mn-doped two-dimensional perovskite (PMA)2PbBr4 were studied. The results show that after manganese doping, the exciton recombination luminescence peak (419 nm) of the original two-dimensional perovskite changed into a transition (608 nm) between the Mn2+ orbital 4T1→6A1, in which an effective energy transfer occurred. The introduction of Mn2+ leads to a certain degree of lattice distortion, and then the exciton lifetime decreases (from 6.51 ns to 0.30 ns); at the same time, the luminescence lifetime brought by Mn2+ is not sensitive to the doping concentration (0.23 ms), because the luminescence corresponds to the transition between 4T1 and 6A1 of Mn2+ at this time. After manganese doping, its optical stability has also been significantly improved. Therefore, manganese doping is an effective means to adjust the wavelength or bandwidth of two-dimensional perovskite and improve the luminous efficiency, which provides the possibility for the application of two-dimensional perovskite in white light lighting.

In this paper, we propose a heterogeneous integrated waveguide platform. The bistable behavior of a micro-ring resonator is observed and analyzed, and the implementation of all-optical memory is shown. The proposed heterogeneous integrated waveguide has strong Kerr nonlinear effect, without the restrictions on thermo-optical effect and free-carrier lifetime. Pure Kerr nonlinear effect enables the ultra-fast all-optical switching. We designed a micro-ring resonator with high quality factor Q = 77565. The bistable behavior was simulated based on coupled mode theory (CMT), and an all-optical memory was realized under the pulse excitation with peak power of 474 fJ and pulse width of 20 ps. Besides, we demonstrated the wavelength addressable four-bit optical memory using four micro-ring resonators cascaded by wavelength division multiplexing. This paper investigates the bistability based on high Kerr nonlinear effect, which provides the possibility of achieving ultra-fast all-optical switching, and shows certain research significance on optical storage, optical switching, and artificial intelligence.

This article presents an improved method for the three-dimensional cultivation of colon cancer cells and the realization of real-time fluorescence imaging using a microfluidic chip. By incorporating endogenous red fluorescent protein into the colon cancer cells, we employed laser confocal microscopy to visualize the cells cultivated within the chip in three dimensions. The expression of intracellular red fluorescent protein allowed for the observation of cell growth status, facilitating real-time monitoring and high-resolution fluorescence imaging. Moreover, immunofluorescence staining was employed to characterize feature proteins indicative of cellular activity, with their fluorescence intensity demonstrating a positive correlation with protein expression. The research findings indicate that the expression of activity-related proteins is influenced by the microenvironment, exhibiting stronger activity in the three-dimensional cultivation on the chip compared to the two-dimensional approach. This suggests that the microenvironment within the chip more closely resembles the actual microenvironment within the human body. This method provides a novel technical approach and experimental platform for further exploration of tumor metastasis mechanisms and the screening of related drugs.

Multi-functionalization is an important development direction of optical fiber chemosensors. A laser-induced self-written waveguide technique is used to prepare optical fiber-hydrogel polymer waveguide-fiber sensing structures. In this structure, the waveguide is coaxially connected to the optical fibers, which ensures the high efficiency of pumping light launching and signal collection. In order to broaden the sensing abilities of the optical fiber-polymer waveguide-fiber (OFWF) sensor, gold nano-particles (AuNPs) are successfully doped into the waveguide session of the OFWF. The AuNPs-doped OFWF sensor is good at spectral detection. We successfully achieved the absorption, fluorescence and Raman spectra measurement of acriflavine hydrochloride. It is believed that the AuNPs-doped OFWF has great potential in various applications.

Aiming at the quantitative weighing system developed by Shanghai Cohere Electronic Technology Co., Ltd. (consisting of a high-precision powder shaking device and a 1/10000 balance), which has nonlinearity and time delay problems due to factors such as powder density, powder fluidity, particle size, humidity, and balance delay during operation, the Smith predictive fuzzy PID controller is used to optimize the control method. Firstly, based on theoretical analysis, the transfer function of the system is obtained, and then a Smith predictive fuzzy PID controller is constructed to adapt to the nonlinearity, time delay, and other characteristics of the system. Finally, this algorithm is substituted into MATLAB to perform simulation, and a 1 g quantitative shaking experiment is carried out in the system. The standard deviation of the Smith predictive fuzzy PID control algorithm and the traditional PID algorithm is 0.0020 and 0.0042, respectively. In conclusion, the Smith predictive fuzzy PID control algorithm has better stability in practical environments and can effectively reduce the weighing error of the system.

To improve the output characteristics of green light lasers, a volume Bragg grating external cavity second harmonic generation semiconductor laser is designed. A reflective volume Bragg grating was used as a feedback element to construct an external cavity semiconductor laser, and a lithium triborate crystal was used for second harmonic generation. The influence of the beam and spectral characteristics of the fundamental frequency light on the beam and spectral characteristics of the frequency doubling light was studied. The experimental results showed that when volume Bragg grating for external cavity mode locking was used, the obtained second harmonic generation also could achieve narrow bandwidth output, and the far field distribution of second harmonic generation was consistent with that of fundamental frequency light. A volume Bragg grating with a diffraction efficiency of 10% was used as an external cavity output mirror. The output wavelength of the semiconductor laser could be stably locked at 1 064 nm. The obtained second harmonic generation wavelength could be stabilized around 532 nm. The spectral linewidth was compressed to about 0.4 nm, and the output power could reach 73 mW.