In biomedical imaging, especially in cellular and single-molecule imaging, multi-wavelength imaging and high resolution are critical performance indicators. Traditional high numerical aperture (NA) optical systems can improve resolution, but chromatic aberration correction is complex and affects the practical application of the system. This research proposes an inverse design method based on multi-wavelength metasurfaces, using superoscillation phase modulation technology to achieve precise control of light fields across different wavelengths while maintaining consistent unit structure. Based on this approach, we designed a metasurface with a numerical aperture (NA) of 0.8, which demonstrates a 3.9 % chromatic aberration tolerance across the 560-740 nm wavelength range, with a focal depth range of 3 to 4 times the wavelength. Building upon this, the structure was further optimized using the adjoint optimization method with the initial structure as a starting point, achieving a full field of view of 20 degrees.Additionally, the structure exhibits polarization-insensitive characteristics. This inverse design method provides a novel solution for chromatic aberration elimination and resolution enhancement in multi-wavelength optical systems, advancing metasurface technology towards practical applications.

To address the issues of agglomeration during magnetic particle capture and the incomplete release of these particles during reuse in microfluidic chips for library preparation, a microchamber was utilized to enhance the dispersion area for magnetic particle capture. Additionally, the release of magnetic particles was achieved through the synergistic action of flow field and magnetic field. The simulation results indicated that as the inlet flow velocity varied from 0.02 m/s to 0.16 m/s and the magnet spacing ranged from 1.2 mm to 1.8 mm, the coverage of magnetic particles in the microchamber increased from 17.29% to 63.59%. Meanwhile, the magnetic particle capture rate decreased from 100% to 35.2%. These processes were further validated through experimental methods. During the release process, the trajectory of magnetic particles under the synergistic effect of flow field and magnetic field aligned with expectations. The captured magnetic particles were released from the microchamber within 12 s, achieving a release rate of 100%.

Chemiluminescence is currently the most widely used immunoassay method in clinical practice, characterized by its high detection sensitivity, high specificity, and rapid processing speed. Traditional chemiluminescence rely on large, complex instruments that require intensive manual maintenance, making it unsuitable for regions with limited medical resources. Developing POCT devices based on centrifugal microfluidics is a feasible solution. However, fully integrating complex assay steps such as sequential reagent release, precise fluid transport, and magnetic beads manipulation into centrifugal microfluidics remains challenging, limiting its application in chemiluminescence. Commonly used integration schemes concentrate on utilization of single trigger-type valves and the resolution of valve activating inevitably decreases as the number increases due to the same triggering mechanism. In our previous work, we introduced new Euler force triggered siphon valves which were different from conventional hydrophilic siphon valves. In this work, we further proposed an integration scheme based on passive valves with different triggering mechanisms to reduce the risk of valve interference, resulting in more precise fluid control and thus better reproducibility of chips. As a validation, we detected total prostate cancer antigen (TPSA) and free prostate cancer antigen (FPSA) using direct chemiluminescence on the chip. The detection process was completed in less than 20 min and limit of detection (LOD) was 0.1 ng/mL for TPSA and 0.08 ng/mL for FPSA, respectively. The chip relies solely on valves for fluid control without external structural intervention, establishing significant advantages in automation of entire platform, which create broad application prospects for early clinical diagnosis.

In the deep-sea environment, the volume available for an in-situ gene sequencer is severely limited. In addition, optical imaging systems are subject to real-time, large-scale defocusing problems caused by ambient temperature fluctuations and vibrational perturbations. To address these challenges, we propose an edge detection algorithm for defocused images based on grayscale gradients and establish a defocus state detection model with nanometer resolution capabilities by relying on the inherent critical illumination light field. The model has been applied to a prototype deep-sea gene sequencing microscope with a 20× objective. It has demonstrated the ability to focus within a dynamic range of ±40 μm with an accuracy of 200 nm by a single iteration within 160 ms. By increasing the number of iterations and exposures, the focusing accuracy can be refined to 78 nm within a dynamic range of ±100 μm within 1.2 s. Notably, unlike conventional photoelectric hill-climbing, this method requires no additional hardware and meets the wide dynamic range, speed, and high-accuracy autofocusing requirements of deep-sea gene sequencing in a compact form factor.

The thermal stability of DNA immobilized on a solid surface is one of the factors that affects the efficiency of solid-phase amplification (SP-PCR). Although variable temperature amplification ensures high specificity of the reaction by precisely controlling temperature changes, excessively high temperatures during denaturation can negatively affect DNA stability. Formamide (FA) enables DNA denaturation at lower temperatures, showing potential for SP-PCR. Research on FA’s impacts on DNA microarrays is still limited, necessitating further optimization in exploring the characteristics of FA in SP-PCR according to particular application needs. We immobilized DNA on a chip using a crosslinker and generated DNA microarrays through bridge amplification based on FA denaturation on our automated reaction device. We optimized the denaturation and hybridization parameters of FA, achieving a maximum cluster density of 2.83 × 104 colonies/mm2. Compared to high-temperature denaturation, FA denaturation required a lower template concentration and milder reaction conditions and produced higher cluster density, demonstrating that FA effectively improves hybridization rates on surfaces. Regarding the immobilized DNA stability, the FA group exhibited a 45% loss of DNA, resulting in a 15% higher DNA retention rate compared to the high-temperature group, indicating that FA can better maintain DNA stability. Our study suggests that using FA improves the immobilized DNA stability and amplification efficiency in SP-PCR.

To meet the challenge of preparing a high-resolution compound eye, this paper proposes a multi-focal-length meniscus compound eye based on MEMS negative pressure molding technology. The aperture is increased, a large field of view angle of 101.14° is obtained, and the ommatidia radius of each stage is gradually increased from 250 μm to 440 μm. A meniscus structure is used to improve the imaging quality of the marginal compound eye so that its resolution can reach 36.00 lp/mm. The prepared microlenses have a uniform shape and a smooth surface, and both panoramic image stitching and moving object tracking are achieved. This technology has great potential for application in many fields, including automatic driving, machine vision, and medical endoscopy.

Hot spot and photonic nanojet (PNJ) are subwavelength focused beams generated from the microsphere or microcylinder. In this paper, we proposed a method of excitation of high-order resonant modes in microcylinder with a high-refractive index cladding and modulation of local modes at the exit end to generate the hot spot. A hot spot with a full width at half maximum waist of 66.70nm(λ/8.47) on the surface is obtained and explained by the wave superposition theory modulated by local modes. The influence of local structures and refractive index on the waist, effective length and exit direction of the hot spot is discussed. The focal position of the hot spot can be gradually moved out and converted to the nanojet by engineering the local modes of the microcylinder. Also, a cubic array chip is suggested for decreasing the difficulty of manufacture. And it shows that number and position of the hot spot can be controlled by adjusting the refractive index and height of the local structure. This work provides a possibility for potential applications in the fields of high-throughput super-resolution near-field imaging, localized excitation and imaging of single-molecule fluorescence.

Compound eye cameras are a vital component of bionics. Compound eye lenses are currently used in light field cameras, monitoring imaging, medical endoscopes, and other fields. However, the resolution of the compound eye lens is still low at the moment, which has an impact on the application scene. Photolithography and negative pressure molding were used to create a double-glued multi-focal bionic compound eye camera in this study. The compound eye camera has 83 microlenses, with ommatidium diameters ranging from 400 μm to 660 μm, and a 92.3 degree field-of-view angle. The double-gluing structure significantly improves the optical performance of the compound eye lens, and the spatial resolution of the ommatidium is 57.00 lp mm−1. Additionally, the measurement of speed is investigated. This double-glue compound eye camera has numerous potential applications in the military, machine vision, and other fields.

This paper proposes a lightweight neural network method based on UNet to accurately detect and localize high -density, low signal-to-noise ratio (SNR) sub -diffraction fluorescence spots in high -throughput fluorescence microscopy imaging. This method combines a squeeze and excitation channel -wise attention mechanism with a residual module to optimize feature information. A density map and offset multioutput architecture are also constructed for direct detection and subpixel localization. The proposed method has been verified on public and simulated datasets, and outperforms current algorithms for low SNR and high -density fluorescent spot detection. Notably, the detection performance of the proposed method is excellent for high -density fluorescent spot that reaches the diffraction limit, such as in images with a resolution of 128 x 128 pixels having 1200 fluorescent spots. The spot detection accuracy (F1 score) of the proposed algorithm exceeds 97. 6%, and the localization error is 0. 115 pixel. Compared with the latest deepBlink method, the F1 of the proposed algorithm has improved by 16.2 percentage points, and the localization error has been reduced by 0. 63 pixel.

As for microparticles (microspheres or microcylinders) that form photonic nanojets (PNJs) in the near field, a curved truncated dielectric microcylinder structure (CSTDM) is investigated by the finite element method which can form ultralong PNJs with the longest effective length: 209.49 λ . Changing parameter h of the structure can realize long dynamic range tuning of the effective length of the PNJ. The effective length varies quasi-periodically with h ; the law of the variation of main indicators of the microcylinder is further discussed, such as the effective length, the working distance, peak electric field intensity, and full width at half height.

AbstractAiming at the problem of preparing high-resolution compound eye, this paper proposes a multi-focal length meniscus compound eye based on MEMS negative pressure molding technology. The aperture is increased while the large field angle of view of 101.14° is obtained, and the ommatidia radius of each stage is gradually increased from 250 µm to 440 µm. A meniscus structure is used to improve the imaging quality of the marginal compound eye, so that the resolution of the compound eye can reach 36.00 lp/mm. The prepared microlenses have a uniform shape and a smooth surface, and we realize panoramic image stitching and moving object tracking. The related technologies have great application potential in the fields of automatic driving, machine vision, medical endoscopy, etc.

压电陶瓷已广泛应用于检测、通讯等各个领域.该文采用外差式激光干涉测量法,开展了压电陶瓷振动特性研究.首先给出了激光外差干涉测振仪测试压电陶瓷振动特性的测量方法,并通过实验测得了压电陶瓷片单点振动的频率响应曲线,同时测量了径向直线上若干点的振动频响曲线,进而进行了整个压电陶瓷圆环表面在其谐振频率点的振动测量.实验结果表明,实测压电陶瓷片的谐振频率为30710 Hz,与其产品标定值30000 Hz存在710 Hz偏差.其圆环表面振动的振型具有不对称性,这对压电陶瓷的应用设计提供了指导意义.

In order to achieve rapid and high spectral resolution detection in the broad band from ultraviolet to near infrared with an atomic emission spectrometer, an ultra-precision rotation stage is used to drive grating rotation to realize spectral segment-scan with high speed and high precision functioning together with an imaging CCD. However, during the scan, the wavelength increment of detector pixel changes nonlinearly with the angle of the grating, and the wavelength increments of different pixels are different, which becomes an obstacle to accurate spectral calibration. To compensate for the nonlinearity of the grating dispersion, the corresponding relationship between the wavelengths of the pixels at both ends of the detector and the rotational angles of the grating is calculated based on the grating equation while the wavelengths of the other pixels are calculated by using the wavelengths of the pixels at both ends with the linear dispersion law. Thus, with this methodology, the calibration of the full band of wavelength is implemented. After calibration, according to the corresponding relationship between the angle and the detection wavelength band, the grating is driven to rotate successively to realize the spectral segment-scan with high resolution and high speed in broad band. The wavelength accuracy and repeatability with this method are tested by using a mercury lamp. The results show that the wavelength accuracy is better than 0.018 nm and the wavelength repeatability is better than 0.001 nm in the wave band from 200 nm to 800 nm.

An optical whispering gallery mode (WGM) resonator supports degenerate counter-propagating modes and the degeneracy is lifted as mode splitting due to Rayleigh scattering. However, quantitative analysis becomes difficult if the resonance experiences weak scattering. Here we develop a spectroscopical method to identify an arbitrary small scatterer using the Fano interference-induced spectral response modification. Scattering information can be revealed by fitting the responses as a function of the field’s phase and intensity. In addition, we show that this modified response helps achieve an ultra-low detection limit for the mode-splitting-based nanoparticle detection method. This approach may be promising in the characterization of high-Q-factor devices, novel sensing methods, and quantum coupling system investigation.

In the traditional background correction algorithm based on the wavelet transform, approximation coefficients considered as frequency responses of background signal are usually set to zero. However, there are many meaningless negative values generated in the background-corrected spectrum because of the calibration errors of this algorithm. Intensities of some weak peaks even become negative and these peaks will disappear after the calibration of negative values. To solve these problems for the background correction of Raman spectrum, an improved intelligent algorithm which utilizes a suppression coefficient to modify approximation coefficients is proposed in this paper. A series of simulation analyses, as well as experimental investigations, are made to test the performance of this algorithm. It is proved that the use of the suppression coefficient could increase the background correction accuracy and decrease the number of meaningless negative values in the reconstructed spectra, which will prevent the disappearance of weak Raman peaks after the calibration of negative values and increase the sensitivity of Raman spectral analysis.

We establish a new quadrature detection system for self-mixing interferometry using two photodiodes and a 22.5-deg rotated beam splitter. The method is based on a rotating beam splitter placed between the laser diode and the measured object, and two quadrature self-mixing signals can be obtained. Then, an arctangent phase algorithm can be used to demodulate the quadrature signal to acquire the object vibration information. This method simplifies the self-mixing signal demodulation process and allows us to demodulate the vibrating displacement more easily. The experimental results demonstrate the feasibility of quadrature detection for self-mixing optical measurement. This Letter provides guidance for the design of self-mixing interferometers.

A beam expanding focusing lens of single scanning laser vibrometer is analyzed and designed by ZEMAX. Firstly, the Gauss He-Ne laser source is simulated, and then the initial structure of the system is calculated. The relationship between the moving distance of the front lens and the laser focusing distance is analyzed, and the spot sizes at different focusing distances are obtained. Finally, the mechanical structure of the adjustable focusing system is designed. The adjustment of the structure is smooth, and the front lens can not rotate. Thereby the errors caused by rotating lens are reduced.

The pillar plate phononic crystal (PC) structure is benefit for the mass loading and liquid detection.A pillar plate phononic crystal point defect is proposed and fabricated in this paper.The band gap calculation is carried out by using the finite element method and the vibration mode of the point defect mode of the phononic crystal is simulated.An AlN acoustic wave sensor based on silicon is fabricated by MEMS processing.The performance of the selected point defect mode is tested and analyzed through the mode selection of the electrode configuration.The results show that the point defect mode with relative high frequency can be obtained through reasonably designing the electrode.In the experiment,the mode frequency of selective incentive is 7.732 MHz and the corresponding Q value is 700 in the air.This provides a theoretical and experimental basis for realizing the liquid phase detection.

In this paper, a phononic crystal (PC) plate with tubular pillars is presented and investigated. The band structures and mode displacement profiles are calculated by using finite element method. The result shows that a complete band gap opens when the ratio of the pillar height to the plate thickness is about 1.6. However, for classic cylinder pillar structures, a band gap opens when the ratio is equal or greater than 3. A tubular pillar design with a void room in it enhances acoustic multiple scattering and gives rise to the opening of the band gap. In order to verify it, a PC structure with double tubular pillars different in size (one within the other) is introduced and a more than 2 times band gap enlargement is observed. Furthermore, the coupling between the resonant mode and the plate mode around the band gap is characterized, as well as the effect of the geometrical parameters on the band gap. The behavior of such structure could be utilized to design a pillar PC with stronger structural stability and to enlarge band gaps.