Abstract:The Fourier transform spectrometer （FTS） is a precision infrared detection instrument. It adopts Michelson interference splitting， and the moving mirror is one of the core components. The uniformity and stability of the moving mirror’s speed directly affect the quality of the subsequent interferogram， so it is necessary to carry out high-precision motion control of the moving mirror. For some FTS with moving mirror in low-speed motion， the traditional M-method can no longer meet the requirements of speed measurement accuracy. In addition， when the moving mirror moves at a low speed， the speed stability is more easily affected by external mechanical disturbance. Based on the stability requirement of the low-speed moving mirror， this paper studies the motion control of the moving mirror based on the T-method measuring speed. It proposes a high-precision algorithm to obtain the measured and expected value of the velocity. By establishing the mathematical model and dynamic equation of the controlled object， the speed feedforward input is obtained， and then the compound speed controller based on the feedforward control is designed. The control algorithm is implemented by the FPGA hardware platform and applied to the FTS. The experimental results show that the peak-to-peak velocity error is 0.0182， and the root mean square （RMS） velocity error is 0.0027. To test the anti-interference ability of the moving mirror speed control system， the sinusoidal excitation force of 5 mg， 7.5 mg， and 10 mg is applied in the moving mirror motion direction on the FTS platform. Under each given magnitude， the scanning of each frequency point in 2~200 Hz is carried out. The experimental results show that the peak-peak velocity error and the RMS velocity error are proportional to the excitation magnitude. Under the 10 mg excitation， the maximum peak-to-peak velocity error is 0.1405， and the maximum RMS velocity error is 0.0448. After analysis， the speed stability of the moving mirror can still meet the performance requirements of the FTS. This design provides a technical means for realizing the speed control of the moving mirror with low speed and high stability. Also， it makes the FTS have wider applications.

Abstract:This paper investigates the impact of extrinsic resistance on the noise performance of deep submicron MOSFETs （metal-oxide-semiconductor field-effect-transistor） using the noise correlation matrix method. Analytical closed-form expressions for calculating the four noise parameters are derived based on the small-signal and noise-equivalent circuit models. The results show strong agreement between simulated and experimental data for MOSFETs with a gate length of 40 nm and dimensions of 4×5 μm （number of gate fingers × unit gate width.

Abstract:This study systematically investigated the influence of deposition rate on the structure， broadband optical properties （1.0-13.0 μm）， and stress characteristics of Germanium （Ge） films. Additionally， a method for enhancing the performance of infrared filters based on rate-modulated deposition of Ge films was proposed. The optical absorption of Ge films in the short-wave infrared （SWIR） and long-wave infrared （LWIR） bands can be effectively reduced by modulating the deposition rate. As the deposition rate increases， the Ge films maintain an amorphous structure. The optical constants of the films in the 1.0-2.5 μm and 2.5-13.0 μm bands were precisely determined using the Cody-Lorentz model and the classical Lorentz oscillator model， respectively. Notably， higher deposition rates result in a gradual increase in the refractive index. The extinction coefficient increases with the deposition rate in the SWIR region， attributed to the widening of the Urbach tail， while it decreases in the LWIR region due to the reduced absorption caused by the Ge-O stretching mode. Additionally， the films exhibit a tensile stress that decreases with increasing deposition rate. Finally， the effectiveness of the proposed fabrication method for an infrared filter with Ge films deposited at an optimized rate was demonstrated through practical examples. This work provides theoretical and technical support for the application of Ge films in high-performance infrared filters.

Abstract:Remote sensing multimodal large language models （MLLMs）， which integrate rich visual-linguistic modal information， have shown great potential in areas such as remote sensing image analysis and interpretation. However， existing knowledge distillation methods primarily focus on the compression of unimodal large language models， neglecting the alignment of features across modalities， thus hindering the performance of large language models in cross-modal tasks. To address this issue， a lightweighting method for remote sensing MLLMs based on knowledge distillation is proposed. This method achieves effective alignment of multimodal information by aligning the outputs across modalities at the feature level. By introducing the reverse Kullback-Leibler divergence as the loss function and combining optimization strategies such as teacher mixed sampling and single-step decomposition， the generalization and stability of the student model are further enhanced. Experimental results demonstrate that the proposed method achieves higher accuracy and efficiency in four downstream tasks of remote sensing image scene classification， visual question answering， visual localization， and image description， significantly reducing the number of model parameters and the demand for computational resources， thereby providing a new solution for the efficient application of MLLMs in the field of remote sensing.

Abstract:Infrared polarization image fusion can fully utilize the polarization information of the scene， compensate for the disadvantage of infrared intensity images in describing high-frequency information such as scene contour edges and texture details， and has unique advantages in target detection and recognition， background noise suppression， and counter camouflage. The article summarized the research progress of infrared polarization image fusion technology from two aspects： single algorithm image fusion and multi-algorithm combination image fusion. It analyzed the design ideas of typical algorithms and summarized the advantages and disadvantages of each algorithm. Based on the current trend where single algorithm serves as the mainstream and multi-algorithm combination as the development trend for infrared polarization image fusion， this paper anticipates its potential future development direction.

Abstract:The InGaAsP material with an energy bandgap of 1.05 eV was grown on InP substrate by all-solid-state Molecular Beam Epitaxy （MBE） technique. The material had no mismatch dislocations between the substrate and the epitaxial layer， and also exhibited high interface quality and luminescence quality. Based on InGaAsP material， single-junction InGaAsP solar cells were grown on InP substrates， and GaInP/GaAs dual-junction solar cells were grown on GaAs substrates. These two separate cells were then bonded together using the wafer bonding technology to fabricate a GaInP/GaAs/InGaAsP triple-junction solar cell. Under the AM1.5G solar simulator， the conversion efficiency of the GaInP/GaAs/InGaAsP wafer-bonded solar cell was 30.6%， achieving an efficiency of 34% under concentration. The results indicate that MBE can produce high-quality InGaAsP material， and that room-temperature wafer bonding technology holds great potential for the fabrication of multi-junction solar cells.

Abstract:Highly matched and precisely locked to the absorption lines of rubidium （Rb） atoms， 780 nm lasers play a crucial role in fields such as quantum computing， precision measurements， and high-sensitivity sensing， with clear requirements for strong coherence and fast tunability. In this paper， based on the self-injection locking and ultra-high quality factor whispering gallery mode （WGM） cavity， a 780 nm narrow linewidth （23.8 kHz） tunable laser with a single longitudinal mode output is verified. More importantly， benefiting from the optimized combined coupling coefficient K and via the lithium niobate electro-optic effect， the laser frequency detuning is effectively improved， with the experimental tuning range reaching 110 pm and the tuning efficiency of 6.4 pm/V. This work provides a high-performance design solution for fast-tunable narrow-linewidth lasers for applications in the near-infrared range， which is expected to play an essential role in the future.

Abstract:Topological semimetal materials have garnered significant interest due to their distinctive electronic structures and unique properties. They serve as a foundation for exploring various physical phenomena including the anomalous Hall effect， topological phase transitions and negative magnetoresistance， while also offering potential solutions to the "THz Gap." This study focuses on the type-II Weyl semimetal tetratellurium iridium niobium （NbIrTe₄） terahertz detector which exhibits a responsivity of 4.36 A/W， a noise equivalent power of 12.34 pW/Hz^1/2 and an anisotropic resistance ratio of 32 at room temperature. This research paves the way for achieving high-performance terahertz detection at room temperature and serves as a reference for investigating the Weyl semimetal.

Abstract:The new active metasurface has the advantages of small size， lightweight and easy integration， so it has an important application prospect in weapon radar intelligent stealth. Based on this， focusing on the requirements of radar intelligent stealth for current weapons and equipment， this paper expounds the methods， approaches and performance advantages of active metasurface in electromagnetic wave regulation， reviews the development history of various active metasurface， and summarizes the research status and future development direction of active metasurface for radar intelligent stealth. It provides the relevant theoretical basis and design reference for the wide application of active metasurface in intelligent stealth of weapon equipment radar.

Abstract:A high-performance oxygen detection system enables real-time online monitoring of critical parameters such as oxygen concentration and flow velocity inside the engine， thereby ensuring optimal operational performance. In flow field testing for engines such as scramjets and aircraft engines， the complex environment—characterized by high temperatures， high pressures， high velocities， and limited measurement space—poses significant challenges to high-performance flow field diagnostics. To address these challenges， an oxygen concentration measurement device based on cavity-enhanced absorption spectroscopy （CEAS） was developed. The system incorporates an embedded optical probe structure and is equipped with multi-directional alignment stages at both the transmitter and receiver ends， enabling straightforward optical path adjustment and alignment for practical engineering applications. Experimental results indicate that， under static conditions， the system measured an oxygen concentration of 20.846 ± 0.97%， showing good agreement with the reference value. In shock tube experiments， although vibrations and airflow disturbances during operation affected measurement accuracy， the system successfully captured three distinct states： before the arrival of the incident shock wave， after the incident shock wave passed but before the reflected shock wave arrived， and after the reflected shock wave passed. The measured trends in oxygen concentration align well with theoretical predictions.