With the rapid development of modern weapon systems， high-precision measurement of explosion timing has become a key factor in evaluating weapon effectiveness and supporting tactical decision-making. To address the limitations of existing detonation timing measurement systems—such as inadequate accuracy， limited detection capability， and high cost，this paper presents the design of a high-precision explosion timing measurement system. The proposed system is capable of accurately capturing the instant of projectile detonation， providing a unified time reference for various test-range measurement and control instruments such as high-speed cameras and theodolites. It further supports the analysis of explosion parameters and damage assessment， enabling rapid localization of explosion timing points within large-scale datasets.

The system consists of five major components　an optical signal acquisition and conversion circuit， an analog signal amplification module， a digital processing core， an analog-to-digital conversion subsystem， and a GPS timing unit. In the optical detection stage， a silicon photodiode BPW20 with a peak sensitivity at 920 nm is selected and paired with an AD825 transimpedance amplifier to perform photoelectric signal acquisition and initial amplification. This configuration offers low dark current and low noise voltage， ensuring stable operation under high signal-to-noise ratio conditions. To further enhance long-range detection capability， a condenser lens optimized using Zemax was incorporated into the optical structure， significantly improving the convergence of incident light. Experimental results show that the addition of the condenser lens increases detection capability by approximately ninefold.

To improve timing accuracy， the system adopts a GPS-disciplined local clock architecture， using the 1 PPS signal as the reference. Through hardware-software co-design， the system obtains and maintains synchronization with the GPS time base. An initial time offset of about 7 μs was observed； to eliminate this error， an All-digital Phase-locked Loop （ADPLL） structure was integrated. By employing phase detection and a PI adaptive regulation mechanism， the local clock is precisely aligned with the 1 PPS signal. Oscilloscope measurements after synchronization indicate that the residual timing error is less than 50 ns， thereby achieving high-precision timekeeping based on a standard crystal oscillator while effectively reducing system cost.

In indoor simulation experiments， the system successfully captured transient LED emissions within a range of 5~30 m， verifying its sensitivity and timing accuracy. In outdoor field tests， the system effectively detected the flash produced by firecracker explosions at distances beyond 100 m and accurately recorded the time corresponding to the optical intensity peak. Comprehensive experimental results demonstrate that the proposed system provides precise， real-time， and reliable detection of explosion light and timing， meeting the requirements of modern test-range applications and showing broad engineering potential.

Future research will focus on system miniaturization and low-power design to enable deployment on mobile platforms such as UAVs， thereby extending its applicability within modern test-range systems.

Intraocular Lens （IOL） is a medical device implanted into the eye， commonly utilized in the treatment of ophthalmic conditions such as cataracts. In clinical practice， implanted IOLs frequently exhibit varying degrees of decentration and tilt. These positional deviations from the ideal alignment can significantly compromise the eye's optical performance. Among the widely adopted monofocal IOLs， which are primarily designed to restore distance vision， two main categories exist： spherical and aspherical monofocal IOLs. Aspherical monofocal IOLs can be further subdivided into two types： Aberration-correcting Intraocular Lens （ACIOL） and Aberration-free Intraocular Lens （AFIOL）. ACIOL is specifically designed to neutralize the cornea's inherent positive spherical aberration， thereby enhancing the quality of distance vision. Under perfect centration conditions， these lenses are capable of delivering optimal optical outcomes. In contrast， AFIOL， while not altering the overall spherical aberration of the eye， demonstrate superior performance in the presence of decentration or tilt. Under such non-ideal positional conditions， they are usually superior to ACIOL. However， while numerous studies have evaluated the optical performance of misaligned IOLs， the underlying causes of performance variations among different aspherical monofocal IOL types remain inadequately explored—a challenge that persists in the field. Some investigations have focused on compensating for refractive errors resulting from IOL tilt or axial shift， whereas others have derived analytical expressions to estimate the specific aberration terms that require correction under given decentration conditions. Despite these valuable efforts， a critical gap remains： the absence of a comprehensive theoretical model capable of simultaneously characterizing the aberrations of the human eye's optical system in the presence of both decentration and tilt. This limitation ultimately hinders a systematic analysis of the factors responsible for optical performance differences among misaligned IOLs.

To address these challenges， this study introduces several key improvements. First， the computational model incorporates the thickness of both the cornea and the IOL. Under realistic implantation conditions， the anterior surface of the IOL may not be perfectly aligned with the iris and can exhibit a measurable offset. This misalignment significantly increases the complexity of aberration calculations， requiring repeated application of the pupil-shift law to both optical surfaces. To enable efficient computation and analysis， the wave aberration coefficients corresponding to primary spherical aberration and primary coma in the pseudophakic eye are explicitly derived. Then， based on functional differences， different axial lengths， and functional principles， three types of ACIOL and three types of AFIOL were designed respectively. The validity of both ACIOL and AFIOL is confirmed through a comprehensive analysis of their Modulation Transfer Function （MTF）， spot diagrams， simulated imaging， and aberration characteristics. The accuracy of these aberration coefficients is subsequently verified using numerical software. During the development of the misaligned pseudophakic eye model， we clarify why the primary spherical aberration field remains invariant under lateral misalignments. Subsequently， we establish the relationship between the primary coma field and the aberration field decenter vector. A mathematical formula for determining the coordinates of the primary coma field center is derived， revealing that under misaligned conditions， the pseudophakic eye possesses only one nodal point for primary coma—a position that is demonstrably influenced by lateral misalignments. Moreover， a comparison was made between the designed IOL and a commercial ACIOL， which showed similar MTF， thus demonstrating the universality of the conclusions drawn in this study.

Based on the misaligned pseudophakic eye model， this study investigates the primary coma field centers of both ACIOL and AFIOL under misaligned conditions. Analytical results indicate that a larger shift in the primary coma field center is associated with a lower MTF. Under decentered conditions， the primary coma field center shift of ACIOL is significantly greater than that of AFIOL. Since the posterior surface spherical aberration is consistent between the two types of IOLs， and the absolute value of the anterior surface spherical aberration in ACIOL is significantly higher than that of the posterior surface， reducing the anterior surface spherical aberration becomes necessary to achieve zero overall spherical aberration. However， as both IOL types share the same dioptric power， their spherical contributions to anterior surface spherical aberration are comparable. Consequently， the reduction of anterior surface spherical aberration must be achieved by decreasing its aspherical contribution， specifically by reducing the conic constant of the anterior surface. This adjustment ensures that the total spherical aberration of the IOL is zero for AFIOL. Once the conic constant of the IOL anterior surface is reduced， the aspherical contribution of the primary coma coefficient of the anterior surface decreases. Given that the aspherical contribution of the posterior surface's primary coma coefficient is zero， this reduction leads to a diminished aspherical contribution to the primary coma field center under decentered conditions. Then， the accuracy of calculating the center of the aberration field is verified through numerical software. Furthermore， by discussing the differences in refractive index between corneal and intraocular structures at different wavelengths and their impact on aberration calculation， the rationality of eye model selection can be enhanced. Finally， by discussing the potential impact of a single parameter such as corneal aberration and thickness， the applicability of the conclusions drawn in this study is demonstrated.

By integrating nodal aberration theory with primary aberration theory， we establish a mathematical model that systematically relates IOL misalignments to the primary aberrations of the entire eye. This analytical framework offers a clear advantage over purely numerical approaches， allowing for a principled evaluation of how IOL decentration and tilt influence overall ocular aberrations. Consequently， the model provides a theoretical basis for explaining the performance differences between the two types of aspherical monofocal IOLs under misaligned conditions. The following conclusion can be drawn： 1） Decentration and tilt of an IOL cause displacement of the primary coma field center from the field center. This displacement is collectively influenced by factors such as the magnitude of IOL misalignment， geometry of lens surface， and refractive index. Moreover， the magnitude of the primary coma field center shift demonstrates a negative correlation with the system's MTF； 2） In the design of aspherical monofocal IOLs， appropriately reducing the conic constant can significantly diminish the primary coma field center shift induced by decentration， thereby enhancing optical performance under misaligned conditions. When the primary coma field center shift is sufficiently minimized， the system's MTF can be maintained nearly unchanged. In summary， the misaligned pseudophakic eye model provides a comprehensive framework for understanding how decentration and tilt influence the performance of aspherical IOLs. This approach offers valuable theoretical guidance for future IOL design and evaluation criteria.

In recent years， the development direction of space optical cameras in various countries can be summarized as high resolution， large aperture， and multi-spectral. Compared with single-band visible light imaging optical systems， visible-infrared dual-band optical systems have advantages. Infrared light can penetrate certain objects to obtain information such as their internal structure and heat distribution. At the same time， infrared optical systems have stronger concealment. When combined with visible light systems for imaging and detection of space targets， it can not only acquire rich spectral information across different bands but also achieve all-weather， round-the-clock space remote sensing detection and imaging. Space optical systems can be divided into three design types： refractive， catadioptric， and reflective. Refractive systems have no light obstruction and are easy to assemble， allowing optical design for large fields of view； however， it is difficult to achieve lightweight designs for large-aperture optical systems. Catadioptric systems can achieve large-aperture optical designs， but for systems with large fields of view and infrared detection requirements， the few available infrared refractive materials have low transmittance， poor thermal stability， and high prices. Additionally， lens chromatic aberration is difficult to correct， lens aperture sizes are limited， making it challenging to widely apply in space exploration. Reflective systems combine advantages such as large aperture， wide field of view， long focal length， broad wavelength range， and lightweight design. Currently， most visible-infrared integrated optical systems adopt catadioptric designs， requiring multiple optical elements to correct chromatic aberration， and are unable to meet design requirements for long focal length， large aperture， wide field of view， and lightweight simultaneously.

This paper adopts a reflective system structure. The initial structure of the system is solved based on paraxial aberration theory， and optimized design is carried out using optical design software， with reasonable field-of-view settings to avoid light obstruction. Considering factors such as aperture， volume， weight， and environmental adaptability of space cameras， the optical system adopts an integrated design scheme of shared aperture with separate fields of view. The visible light and mid-wave infrared bands share the front-end coaxial three-mirror primary and secondary mirrors. At the rear end， the fields of view are split and redirected via two fold mirrors into the visible light imaging path and the mid-wave infrared imaging path， achieving simultaneous dual-band imaging. To minimize the aperture size of the primary mirror， the first image plane is located near the center of the primary mirror. For the visible light subsystem， a coaxial three-mirror structure is used for an off-axis field； for the mid-wave infrared subsystem， the front end consists of the primary and secondary mirrors of the visible light subsystem， and the light path enters the rear three-mirror anastigmatic off-axis structure via a fold mirror. Regarding detector selection， the optical system uses a visible light TDI-CMOS with 12 288×128 pixels， 7 μm pixel size， and three identical detectors arranged in a ‘zigzag’ pattern on the image plane， utilizing only a part of the non-vignetting region of the image plane， achieving a 36 000×128 pixel array and 25.2 km swath width. The mid-wave infrared subsystem uses a large-format cooled infrared detector with 3 000×2 500 pixels and 18 μm pixel size. This detector consists of a glass window， filter， cold stop， and focal plane， with a distance of 90 mm between the focal plane and the cold stop.

The working wavelength range of the visible light subsystem is 0.45~0.9 μm， with a focal length of 5 m， an F-number of 10， and a field of view of 0.7°×2.3°. At an orbital position of 500 km， the imaging swath width is greater than 20 km. The working wavelength range of the mid-wave infrared subsystem is 3~5 μm， with a focal length of 1.5 m， a field of view of 0.2°×2°， an F-number of 3， and 100% cold stop efficiency. The two optical systems share the primary and secondary mirrors of a coaxial three-reflector system at the front end， achieving simultaneous dual-band operation through field-of-view segmentation. The entire system uses eight reflective elements. To meet system specifications and correct aberrations， the three mirrors of the front-end three-reflector system use 6th-order aspheric surfaces， while the three mirrors of the mid-wave infrared system adopt freeform surfaces. The imaging quality of the visible and mid-wave infrared subsystems is evaluated using spot diagrams， modulation transfer functions， and distortion assessments. For both subsystems， the spot diagram RMS radii are smaller than the Airy disk radius， the MTF values at the Nyquist frequency are close to their respective diffraction limits， and distortion is controlled within an acceptable range.

A reflective optical system integrating visible and mid-wave infrared light was designed based on paraxial optical theory. This study also verifies the manufacturability of freeform surfaces in engineering practice. The maximum deviation between the freeform surfaces and the optimal aspheric surfaces does not exceed 65 μm， meeting current processing standards. A defocus analysis indicates that the system maintains good imaging quality within the depth of focus. Finally， considering current lens fabrication and assembly conditions， and based on tolerance allocations from previous reflective systems， a tolerance analysis was conducted using the system's rear intercept as a compensating quantity. The results show that the system has good tolerance performance. In summary， the designed optical system meets the initial design specifications， does not require consideration of secondary spectral issues from transmissive elements， affords good imaging quality， and possesses practical engineering feasibility.

High-magnification beam expansion optical systems are critical components in space-based active optical detection and long-range laser transmission， imposing stringent requirements on beam collimation performance， energy utilization efficiency， and structural compactness. Increasing the beam expansion ratio can effectively suppress laser beam divergence and improve far-field spot quality， but it typically leads to a significant increase in system volume and a sharp rise in the difficulty of aberration control. Traditional transmissive beam expansion systems are limited by their clear aperture and face challenges such as thermal effects and material absorption under high-power laser conditions； coaxial reflective systems inevitably suffer from central obscuration and energy loss. Although off-axis reflective systems can avoid these defects， existing designs generally exhibit limitations in beam expansion ratio， design complexity， and excessive overall volume. To address these issues， this paper proposes a design method for a high-magnification compact off-axis three-mirror afocal optical system， aiming to achieve a high beam expansion ratio while maintaining system compactness and reducing the structural design difficulty of off-axis systems.

Large-aperture planar optical components are key parts of the optical systems in high-end equipment such as photolithography machines and laser fusion experimental devices. Full-aperture polishing， also known as continuous polishing， is an important processing method for large-aperture planar optical components. The surface conditioning of polishing pads has been a research focus for scholars both domestically and internationally. Existing research results indicate that effective conditioning is one of the primary factor to enhance the processing accuracy of optical components. For polishing pads with a meter-scale diameter， such as 1 200 mm， turning or grinding processes are typically employed to achieve surface conditioning. However， these methods are not only time-consuming but also struggle to achieve high-precision finishing on the pad surface. Efficient and high-precision conditioning of meter-scale polishing pad surfaces has long been a challenge in the optical component polishing process.

This paper proposes a method for surface topography conditioning of tin polishing pads through temperature field control. A composite polishing pad consisting of tin-aluminum-cast iron is constructed with three kinds of thin plates. A thermal field control system for the composite polishing pad is designed to investigate the internal temperature field distribution patterns of the pad under the influence of a controlled thermal field， and a gradient model of the internal temperature field within the composite polishing pad is established. Based on the bimetallic thermal deformation effect， five thermal stress distribution equations are established on the neutral surface of the three-layer composite polishing pad. By setting boundary conditions， a differential equation for thermal stress elastic deformation of the composite pad is established， and a mathematical model for surface thermal deformation of the tin polishing pad with parameter t_{\mathrm{c}\mathrm{o}\mathrm{n}\mathrm{t}} as the variable is obtained through solving the equation.

Using finite element simulation software， a simulation analysis was conducted on the thermal deformation of the composite material polishing pad's surface. The ambient temperature field was set to 20 ℃， with constraints and a controlled thermal field applied to the bottom surface of the composite polishing pad. When the parameter t_{\mathrm{c}\mathrm{o}\mathrm{n}\mathrm{t}} of the controlled thermal field was set between 16 and 19 ℃， the thermal deformation of the polishing pad's surface was simulated， and the contour， peak value， and average value of the thermal deformation were analyzed. The simulation results indicated that when the controlled thermal field parameter t_{\mathrm{c}\mathrm{o}\mathrm{n}\mathrm{t}} was set to 20 ℃， there was no temperature gradient change within the composite polishing pad， and no thermal deformation occurred on its surface. However， when t_{\mathrm{c}\mathrm{o}\mathrm{n}\mathrm{t}} was less than 20 ℃， the composite material polishing pad exhibited an overall concave-shaped thermal deformation， and the magnitude of the thermal deformation became more pronounced as t_{\mathrm{c}\mathrm{o}\mathrm{n}\mathrm{t}} decreased. Experiments were conducted to validate the regulation law of the thermal field on the surface of a tin polishing pad. Ensuring an ambient temperature of 20 ℃ in a constant-temperature workshop， measurement tools such as laser displacement sensors were used to measure the surface of the polishing pad. The deformation law of the polishing pad's surface was examined at parameter t_{\mathrm{c}\mathrm{o}\mathrm{n}\mathrm{t}} values ranging from 16 to 19 ℃. Finally， through nine sets of processing experiments on optical components， the impact of the parameter t_{\mathrm{c}\mathrm{o}\mathrm{n}\mathrm{t}} on the processing results was verified. The experimental and simulation results showed consistency in the trend of thermal deformation of the polishing pad's surface. Moreover， by adjusting the thermal field control parameter t_{\mathrm{c}\mathrm{o}\mathrm{n}\mathrm{t}}， the surface accuracy of the processed optical components was optimized.

Through theoretical analysis， simulation， and experimental verification， the paper draws the following conclusions： 1） A controllable thermal deformation prediction mathematical model for the surface topography of the polishing pad was established based on the multi-metallic thermal deformation effect； 2） A finite element model for thermal field regulation of the polishing pad was developed and experimentally validated. Within the temperature range t_{\mathrm{c}\mathrm{o}\mathrm{n}\mathrm{t}} of 16 ℃ to 19 ℃， the finite element analysis results of thermal deformation of the polishing pad were consistent with the experimental results in terms of their changing trends； 3） The thermal deformation generated by the polishing pad thermal field regulation system is the greatest at t_{\mathrm{c}\mathrm{o}\mathrm{n}\mathrm{t}}=16 ℃， with a maximum deformation of 16.9 μm and an average deformation of 12.5 μm； it is the smallest at t=19 ℃， with a maximum deformation of 2.2 μm and an average deformation of 2 μm； 4） Adjusting the parameter t_{\mathrm{c}\mathrm{o}\mathrm{n}\mathrm{t}} can enhance the processing accuracy of the component surface. When t_{\mathrm{c}\mathrm{o}\mathrm{n}\mathrm{t}}=18 ℃， the polishing accuracy of planar optical components is the highest. Compared to when t_{\mathrm{c}\mathrm{o}\mathrm{n}\mathrm{t}}=20 ℃ and t_{\mathrm{c}\mathrm{o}\mathrm{n}\mathrm{t}}=16 ℃， the surface accuracy PV value improves by an average of 20%， and the RMS value improves by an average of 15%； 5） According to the comparative analysis， the mathematical model of thermal deformation on the polishing pad surface and the simulation analysis cannot accurately predict specific values of the thermal deformation. Precise model analysis will be conducted in subsequent research.

Mid-wave infrared interference spectral imagers possess unique advantages in gas detection and identification due to their wide characteristic spectral coverage， high-throughput detection capability， and multi-channel sampling. Particularly in daily inspection and early warning of chemical gases and rapid emergency response to leakage scenarios， they can provide early warnings of disasters at the initial stage of gas leakage， preventing the situation from escalating. After a gas leak occurs， without requiring personnel to enter the site， they can quickly identify the type of leaking gas and the distribution of its diffusion concentration， providing first-hand on-site data for the evaluation of emergency response plans. However， traditional point-scan and area-scan interference spectral imaging configurations face significant limitations in enhancing lightweight， compact design， and stability. It is of great significance to research and design interference spectral imaging instruments that meet the high demands for mobility， adaptability to complex environments， field of view coverage， and lightweight compactness in specific application scenarios. Additionally， as interference spectral imagers require high precision in detector pixel intensity detection， it is necessary to study the analysis and suppression methods of infrared stray radiation in complex scenarios.

This paper proposes a spectral imaging system based on static interference modulation using a stepped micro-mirror. The optical configuration of the system is shown in Figure 1. The scanning telescope imaging lens assembly achieves wide-field one-time convergence imaging onto the stepped micro-mirror for interference modulation， and the image is then relayed onto the detection focal plane through the relay imaging lens group. A cylindrical design is introduced to compensate for the high-order astigmatism introduced by the interference beam-splitting system. Achromatic broadband design and athermalization across a wide temperature range are achieved through hybrid refractive-diffractive and aspheric designs， resulting in a static Modulation Transfer Function （MTF） better than 0.7 at the cutoff frequency. To analyze infrared stray radiation， a stray radiation model for the interference spectral imaging system was constructed. The materials and surface radiation scattering characteristics of the optomechanical structure were defined， and ray tracing was performed. Based on the tracing results， a stray radiation suppression structure was designed， achieving infrared radiation suppression at the level of 10⁻⁵.

The telescope imaging lens group was optimized with an image-space telecentric design， while the relay imaging lens group adopted an object-space telecentric design， achieving a perfect match in a dual-high telecentric optical system. By employing hybrid refractive-diffractive and aspheric designs， the system demonstrated excellent performance in the mid-wave infrared band of 3 μm-5 μm across a temperature range of -40 ℃ to 60 ℃. The static MTF exceeded 0.7 at 17 lp/mm， distortion was controlled within 0.2%， and the RMS radius of the imaging spot was less than 5.9 μm， meeting all imaging quality requirements. A stray radiation simulation model for the interference spectral imaging optomechanical system， as illustrated in Figure 7， was constructed. Stray radiation tracing was performed for typical field light paths， and based on the analysis results， efficient suppression was achieved through blackbody extinction treatment and dedicated stray radiation suppression structures. This reduced the infrared stray radiation energy ratio from an initial level of 10⁻² to 10⁻⁵. Imaging detection experiments on long-distance target scenes using an engineering prototype demonstrated excellent image quality. The MTF test of the prototype of high-precision alignment principle shows that the actual MTF of the designed imaging system is better than 0.32 at the cut-off frequency.

The infrared spectral imaging system based on static interference modulation with a stepped micro-mirror successfully achieves high-quality remote sensing imaging， identification and analysis of gases. The adoption of achromatic methods using cylindrical lenses and hybrid refractive-diffractive lenses， together with the stray radiation suppression method proposed in this paper， has all yielded the expected effects in optimizing imaging quality， which is proven to be effective and can serve as a reference for research in the same field. In addition， the instrument's volume is reduced by a quarter and its weight by approximately 60%， which also provides a valuable contribution to the miniaturization process of such imaging systems.

Precise micro-displacement measurement technology plays a critical role in real-time defect monitoring during manufacturing processes， ensuring adherence to accuracy standards and significantly reducing scrap loss. Chromatic confocal displacement measurement systems operate based on the principles of optical dispersion and confocal technology. Through chromatic encoding， a wavelength-axial position mapping relationship is established， while confocal imaging decodes the reflected spectrum. This enables real-time displacement measurement with sub-micrometer accuracy within a millimeter range， simultaneously providing nanometer-level resolution and robust environmental adaptability. The measurement range and accuracy are constrained by the axial dispersion and aberrations of the dispersive objective. To expand the measurement range and enhance the accuracy of the chromatic confocal displacement sensing system， a secondary dispersion objective based on Gradient-index （GRIN） fiber was designed in this study. The Physics-Informed Neural Network （PINN） algorithm was leveraged in conjunction with ZEMAX software simulation to broaden the system's chromatic dispersion while achieving comprehensive compensation and correction of aberrations in both the secondary dispersion objective and the pre-dispersion GRIN fiber.

Firstly， based on the working principle of chromatic confocal displacement sensors， a GRIN fiber-based chromatic confocal system was proposed. A pre-dispersion unit employing GRIN fiber was established according to its refractive index distribution and the Cauchy dispersion model. The relationship between wavelength and axial dispersion was derived. The chromatic focal shift of the GRIN fiber at different pitch numbers was simulated and analyzed. It was determined that at a GRIN fiber pitch number of m=5， an axial pre-dispersion of 1.496 mm could be achieved， with a linearity R² of approximately 95%. Subsequently， based on Hamiltonian optics theory， the aberrations introduced by the GRIN fiber were derived. Based on the calculated equivalent object position of the GRIN fiber pre-dispersion unit and aberration theory， the GRIN fiber aberrations were analyzed. A secondary dispersion objective was then specifically designed. Its dispersion performance was analyzed and aberrations were optimized using ZEMAX. Finally， to improve system resolution and correct aberrations， an aberration correction method employing PINN combined with ZEMAX for closed-loop verification was proposed. A dataset correlating “lens parameters” with “Zernike aberrations” was established using ZEMAX. Combined with aberration data from the pre-dispersion GRIN fiber， PINN was utilized to predict feedback and perform iterative optimization. This facilitated comprehensive aberration correction and optimized axial dispersion linearity.

Within the operating wavelength range， the corrected spherical aberration values were significantly lower than pre-correction levels， with particularly pronounced correction in the short-wavelength region. Post-correction spherical aberration values for all wavelengths were markedly optimized， demonstrating effective spherical aberration correction. The aberration correction model demonstrated strong generalization capability， and the overall model training was effective， confirming successful aberration correction. The effectiveness of the aberration correction methodology using ZEMAX software combined with the PINN algorithm for closed-loop verification was thus validated. Following algorithmic optimization， a new optimized dispersive objective lens group was obtained. Results demonstrate that the maximum system aberration was reduced below 10 μm. Total axial dispersion reached 4.34 mm with a linearity R² of 99.84%. Theoretical resolution was approximately 25 nm. In the optimized system， the RMS spot radius at the focal point for each wavelength across the visible spectrum was smaller than the Airy disk， achieving diffraction-limited performance and meeting high-precision displacement measurement requirements. This study provides novel chromatic confocal system optimization， enhancing displacement measurement performance and advancing practical engineering implementation.

Intense solar activities （such as coronal mass ejections and solar flares） release a large number of high-energy charged particles. When these particles reach Earth， they interact with the magnetosphere and trigger magnetic storms through processes like particle precipitation. The duration of magnetic storms can range from several hours to days. During this period， they cause ionospheric disturbances and drastic changes in the geomagnetic field， leading to disruptions in on-orbit satellite communications and shortwave broadcasting， significant degradation or even loss of lock in the positioning accuracy of global navigation satellite systems， and an increased risk of accelerated orbital decay for low-orbit satellites due to sudden increases in atmospheric drag.

During magnetic storms， precipitating particles collide with the upper atmosphere at the poles along magnetic field lines， exciting the generation of auroras. The radiation characteristics of auroras are directly related to the flux and energy of the incident particles. Therefore， detecting the morphology of auroras in specific wavelength bands has become a key method for studying solar activities.During magnetic storms， precipitating high-energy particles collide with neutral atmospheric components （such as atomic oxygen and nitrogen molecules） above Earth's poles. Through excitation and ionization processes， these collisions produce auroral radiation covering wavelengths from visible light to the far ultraviolet. Among this radiation， the emission intensity of the LBH band of nitrogen molecules （N₂）—located in the far ultraviolet range of 160~180 nm—has a direct and sensitive quantitative relationship with the energy flux of the precipitating particles.

Far ultraviolet radiation is effectively absorbed by the upper atmosphere， enabling its observation even in sunlight. However， achieving high-precision imaging of N₂ LBH band auroral radiation faces two core technical challenges. Firstly， the dynamic range of auroral brightness under natural conditions is extremely wide. Imaging across a range from approximately 100 Rayleigh （R） to over 30 000 Rayleigh （30 kR） during intense activity periods requires the instrument to have an extremely high linear dynamic range. Secondly， in the far ultraviolet band， stray light interference from non-target sources （such as the Sun and geocoronal background） is extremely strong， which can easily overwhelm weak auroral signals. This places extremely stringent requirements on the system's internal stray light suppression capability.

To capture the full dynamic range （100 R~30 kR） of N₂ LBH band （160~180 nm） auroral radiation and overcome the challenges of weak far ultraviolet signals and strong background interference， this study developed an optical system based on a coaxial four-reflection structure. The core of the instrument's performance lies in its large dynamic range detection capability and high stray light suppression level. Through targeted optical design， simulation， and testing， the system ultimately achieved a signal-to-noise ratio （SNR） > 1.5 for extremely weak signals （100 R）， ensuring the reliable extraction and detectability of weak signals. For strong signals （30 kR）， the SNR reached > 30， guaranteeing measurement accuracy and the upper limit of dynamic range during intense auroral activity. Meanwhile， the stray light suppression level reached 10^-3 within the 160~180 nm operating band and exceeded 10^-9 in the non-operating band of 200~1 000 nm， thereby effectively extracting real auroral signals from complex optical backgrounds.

This instrument can continuously monitor the spatiotemporal evolution of the position， morphology， scale， and intensity distribution of the auroral oval. Through inversion and analysis of these high-quality image data， we can quantitatively obtain core parameters such as information on precipitating particles and their energy flux. This deepens the scientific understanding of magnetic storm triggering mechanisms， energy coupling processes， and evolution laws. It provides crucial data support and technical backing for accurate magnetic storm forecasting， space weather modeling， and ensuring the stable operation of on-orbit satellites and ground communication systems， boasting significant scientific value and broad application prospects.

Fiber-optic microphones have emerged as an innovative solution in the field of acoustic sensing due to their compact size， excellent immunity to electromagnetic interference， and superior insulation performance. These attributes make them ideal for use in various challenging environments such as power systems， healthcare， petrochemical industries， and national defense. However， despite these advantages， traditional fiber-optic microphones still face challenges in terms of sensitivity， stability， and insulation， particularly in high-performance or demanding conditions. Some existing designs struggle with low sensitivity in detecting weak acoustic signals or may experience degradation in performance due to material instability and electromagnetic interference under extreme conditions. Additionally， ensuring stable insulation properties in high-temperature or harsh electromagnetic environments remains a challenge for many fiber-optic microphone designs. Therefore， this work proposes and fabricates a novel high-sensitivity fiber-optic microphone featuring a dual-rib diaphragm structure.

The microphone unit consists primarily of a dual-rib diaphragm， a single-mode optical fiber， and a glass sleeve， which work in synergy to convert acoustic signals into optical signals for high-precision measurement. The diaphragm's design was optimized through finite element simulations to achieve the desired resonance characteristics and enhance its acoustic sensitivity. Specifically， the ribbed diaphragm structure was designed to increase its flexibility， thereby improving its response sensitivity to pressure changes. To fabricate the diaphragm， we employed a picosecond laser micro-nano machining system， which allowed us to achieve high precision and fine features in the diaphragm's ribbed structure. This fabrication process ensures that the diaphragm can withstand mechanical stresses during acoustic signal detection while maintaining high sensitivity.

The fabricated fiber-optic microphone exhibits a high sensitivity of 1 418.9 mV/Pa and a signal-to-noise ratio of 60.47 dB at a resonance frequency of 15.58 kHz， demonstrating excellent performance in acoustic signal acquisition. The microphone's high sensitivity makes it suitable for detecting weak acoustic signals， even in environments with significant background noise. Moreover， the microphone displays a strong directional response， which is critical for applications that require precise localization of sound sources. These characteristics make it an excellent candidate for use in a variety of industrial and scientific applications， where accurate and reliable sound detection is required.

The potential applications of this high-sensitivity fiber-optic microphone are vast. It is particularly suited for power sensing， where it can be used to detect weak acoustic signals from power equipment， monitor partial discharges， diagnose faults， and enable online monitoring of power lines. The microphone's immunity to electromagnetic interference and high sensitivity make it ideal for use in environments with high levels of electrical noise. In addition， the microphone's ability to detect low-level acoustic signals makes it a promising tool for applications in healthcare， such as monitoring bodily sounds， as well as in the petrochemical industry for detecting gas leaks and machinery failures. Beyond these initial applications， the fiber-optic microphone holds promise for many other emerging fields. For example， it could be integrated into advanced monitoring systems for industrial automation， where real-time acoustic feedback is used for predictive maintenance and early detection of mechanical failures. In the field of robotics， the microphone's small size and high sensitivity could be leveraged in autonomous systems for environmental sound detection and localization. Additionally， as wireless technology continues to advance， fiber-optic microphones could be used in conjunction with wireless communication systems for remote sensing applications， further extending their potential. Future research will focus on optimizing the diaphragm design to achieve a broader frequency response and enhancing the microphone's robustness in extreme environments. Additionally， efforts will be directed at improving the signal processing capabilities of the fiber-optic microphone to ensure high-performance operation in complex and diverse environments. This work lays a solid foundation for the development of high-sensitivity fiber-optic microphones， which will undoubtedly lead to their widespread application in high-performance acoustic sensing fields， offering substantial benefits for industrial， scientific， and healthcare applications.

The Underwater Wireless Optical Communication （UWOC） system has advantages such as high transmission speed and high reliability. The presence of ocean turbulence can induce fluctuations in light intensity， thereby degrading the communication performance of the system. Quasi-Cyclic Low-Density Parity-Check （QC-LDPC） codes can mitigate the impact of ocean turbulence on Bit Error Rate （BER） and enhance the communication performance of UWOC systems. However， research on QC-LDPC codes in UWOC has primarily focused on theoretical analysis and numerical simulation. The gain effect of QC-LDPC coding may vary under different modulation formats， and specific experimental verification is lacking. In response to the absence of experimental research on the coding gain of different modulation formats in turbulent environments， this paper investigates the influence of QC-LDPC codes on the coding gain of different modulation formats in weak ocean turbulent channels under mixed coding modulation schemes.

A mathematical simulation model for weak turbulent channels in UWOC is established based on the Log-normal distribution. The check matrix H is constructed using the Dayan sequence， and QC-LDPC encoding is carried out based on the minimum row-column product LU decomposition algorithm to obtain the encoded sequence， which exhibits lower computational complexity compared to direct encoding algorithms. At the receiving end， the Minimum Sum Algorithm （MSA） with low computational complexity is selected for decoding， which is convenient for hardware implementation. The coding gain and communication characteristics of QC-LDPC encoding under different modulation formats， scintillation indices， transmission distance， encoding lengths， and other parameters are simulated and analyzed. Subsequently， a blue-green laser communication experimental platform is designed and built based on a simulated ocean turbulence pool， and comparative experimental research is conducted on the communication performance of QC-LDPC-encoded ocean turbulence optical communication with multiple modulation formats at a transmission distance of 1.5 m and a transmission rate of 10 Mbps. Field Programmable logic Gate Array （FPGA） is employed for QC-LDPC encoding， signal modulation and demodulation. Temperature-induced turbulence is simulated by injecting hot water of different temperatures into a transparent water tank， and salt-induced turbulence is simulated by injecting salt water of different concentrations， and normalized scintillation index {\delta }_{\mathrm{I}}^{\mathrm{2}}is introduced to describe the fluctuation of light intensity at the receiving end， in order to measure turbulence intensity. Aiming to research the encoding gain of QC-LDPC for different modulation formats in weak turbulence environments.

The simulation results indicate that the performance improvement brought by adding QC-LDPC encoding in low Signal-to-Noise Ratio （SNR） On-Off Keying （OOK） modulation and Binary Phase-Shift Keying （BPSK） control modulation may be insufficient to offset the increase in decoding complexity， leading to an increase in the BER. Incorporating techniques such as low-pass filtering or probability shaping at the receiving end to improve the waveform can appropriately reduce the BER and increase the encoding gain. The BER of the QC-LDPC coded Differential Phase-Shift Keying （DPSK） modulation system decreases as the code length increases， and the best anti-turbulence effect is achieved when the code length is 2 400. In contrast， the BER of the QC-LDPC coded DPSK modulation system increases with the increase in the scintillation indices， communication distance， and data rate. When the communication distance is 10 m and the scintillation indices is 0.14， the BER of DPSK modulation with QC-LDPC coding is reduced to 4×10⁻⁵. The experimental results show that QC-LDPC encoding can effectively mitigate the impact of weak turbulence on the BER. Compared with the uncoded modulation format， when the BER is 10⁻⁵， the encoding gains of QC-LDPC encoding for OOK modulation in tap water， temperature-induced turbulence （{\delta }_{\mathrm{I}}^{\mathrm{2}}=0.056）， and salt-induced turbulence （{\delta }_{\mathrm{I}}^{\mathrm{2}}=0.034） environments are 0.46 dB， 0.49 dB， and 1.31 dB， respectively； while the encoding gains for DPSK modulation are 0.83 dB， 0.79 dB， and 1.63 dB， respectively. The QC-LDPC encoding gains for OOK modulation and DPSK modulation in salt-induced turbulence are higher than those in temperature-induced turbulence.

The coding gain of QC-LDPC codes for OOK modulation and DPSK modulation in salt-induced turbulence is higher than that in temperature-induced turbulence. Adding the mixed modulation of QC-LDPC coding in the UWOC system is conducive to reducing the underwater turbulence effect and has a better turbulence suppression effect compared with DPSK modulation alone. The combination of the QC-LDPC+DPSK coding modulation system has higher coding gain and better anti-interference ability compared with the QC-LDPC+OOK coding modulation system.