To improve the exposure contrast of the scanning beam interference lithography (SBIL) system, a mathematical model of scanning exposure that includes the direction error of the measurement mirror is established. The effect of the angle between the interference fringe direction and the X-axis measurement mirror direction on the exposure contrast is analyzed. An accurate method for interference fringe direction measurement based on the heterodyne interferometry measurement method of the metrology grating and phase shift interferometry is proposed. This method combines the diffraction characteristics of the metrology grating and the phase shift algorithm to calculate the angle between the interference fringe direction and the measurement mirror direction accurately and adjust it. Experiments show that this angle reaches 0.6777 µrad, which meets high-precision grating fabrication requirements. Exposure comparison experiments performed at various angles show that a smaller angle between the interference fringe direction and the measurement mirror direction leads to better grating groove production by scanning exposure, which is consistent with the theoretical analysis. The accuracy of the theoretical analysis and the feasibility of the interference fringe direction adjustment method are verified, laying a foundation for high-quality grating fabrication by the SBIL system.

To improve grating manufacturing process controllability in scanning beam interference lithography (SBIL), a novel method for exposure dose monitoring and control is proposed. Several zones in a narrow monitoring region are fabricated on a grating substrate by piecewise uniform scanning. Two monitoring modes are given based on the different widths of the monitoring region. The monitoring curve of the latent image diffraction efficiency to scanning velocity is calculated by rigorous coupled wave analysis. The calculation results show that the exposure dose in SBIL can be monitored by the shape change of the monitoring curve, and an optimized scanning velocity can be selected in the monitoring curve to control the exposure dose.

Accurate wind-speed prediction plays an important role in improving the operation stability of wind-power generation systems. However, the inherent complexity of meteorological dynamics poses a major challenge to forecasting accuracy. In order to overcome these limitations, we propose a new hybrid framework, which combines variational mode decomposition (VMD) for signal processing, enhanced quantum particle swarm optimization (e-QPSO), an improved walking optimization algorithm (IHOA) for feature selection and the long short-term memory (LSTM) network, and which finally establishes a reliable prediction architecture. The purpose of this paper is to optimize VMD by using the e-QPSO algorithm to improve the problems of excessive filtering or error filtering caused by parameter problems in VMD, as the noise signal cannot be filtered completely, and the number of sources cannot be accurately estimated. The IHOA algorithm is used to find the optimal hyperparameters of LSTM to improve the learning efficiency of neurons and improve the fitting ability of the model. The proposed e-QPSO-VMD-IHOA-LSTM model is compared with six established benchmark models to verify its predictive ability. The effectiveness of the model is verified by experiments using the hourly wind-speed data measured in four seasons in Changchun in 2023. The MAPE values of the four datasets were 0.0460, 0.0212, 0.0263, and 0.0371, respectively. The results show that e-QPSO-VMD effectively processes the data and avoids the problem of error filtering, while IHOA effectively optimizes the LSTM parameters and improves prediction performance.

Variable-period scanning beam interference lithography (VP-SBIL) can be used to fabricate varied-line-spacing (VLS) plane gratings. The exposure phase modulation method to pattern a VLS grating with a desired groove density must be carefully devised. In this paper, a mathematical model of the total exposure dose for VLS plane grating fabrication is established. With model-based numerical calculations, the phase modulation effects of the parameters, including the fringe locked phase, fringe density, and step size, are analyzed. The parameter combinations for the phase modulation are compared and chosen, and the optimal coordinate for phase compensation is selected. The calculation results show that the theoretical errors of the groove density coefficients can be controlled within 1e-8. The mathematical model can represent the deposited exposure dose for patterning VLS gratings during the lithography process, and the chosen parameters and proposed phase modulation method are appropriate for patterning VLS gratings with VP-SBIL.

To obtain a good interference fringe contrast and high fidelity, an automated beam iterative alignment is achieved in scanning beam interference lithography (SBIL). To solve the problem of alignment failure caused by a large beam angle (or position) overshoot exceeding the detector range while also speeding up the convergence, a weighted iterative algorithm using a weight parameter that is changed linearly piecewise is proposed. The changes in the beam angle and position deviation during the alignment process based on different iterative algorithms are compared by experiment and simulation. The results show that the proposed iterative algorithm can be used to suppress the beam angle (or position) overshoot, avoiding alignment failure caused by over-ranging. In addition, the convergence speed can be effectively increased. The algorithm proposed can optimize the beam alignment process in SBIL.

Currently, the engineering of miniature spectrometers mainly faces three problems: the mismatch between the number of filters at the front end of the detector and the spectral reconstruction accuracy; the lack of a stable spectral reconstruction algorithm; and the lack of a spectral reconstruction evaluation method suitable for engineering. Therefore, based on 20 sets of filters, this paper classifies and optimizes the filter array by the K-means algorithm and particle swarm algorithm, and obtains the optimal filter combination under different matrix dimensions. Then, the truncated singular value decomposition-convex optimization algorithm is used for high-precision spectral reconstruction, and the detailed spectral reconstruction process of two typical target spectra is described. In terms of spectral evaluation, due to the strong randomness of the target detected during the working process of the spectrometer, the standard value of the target spectrum cannot be obtained. Therefore, we adopt the method of joint cross-validation of multiple sets of data for spectral evaluation. The results show that when the random error of +/− 2 code values is applied multiple times for reconstruction, the spectral angle cosine value between the reconstructed curves becomes more than 0.995, which proves that the spectral reconstruction under this algorithm has high stability. At the same time, the spectral angle cosine value of the spectral reconstruction curve and the standard curve can reach above 0.99, meaning that it realizes a high-precision spectral reconstruction effect. A high-precision spectral reconstruction algorithm based on truncated singular value-convex optimization, which is suitable for engineering applications, is established in this paper, providing important scientific research value for the engineering application of micro-spectrometers.