【摘要】 针对高温（～2000 K）目标探测过程中杂散辐射干扰问题，传统遮光罩虽然可以有效抑制系统内外的杂散辐射，但其自身在中远红外波段（3～14μm）的热辐射会湮没高温样品发出的辐射，严重干扰探测精度。据此提出一种“前黑后白”遮光罩设计方案。结果表明：该构型在保持对其视场外杂散辐射抑制能力的前提下，其中远红外波段自身杂散辐射通量较传统全黑构型显著下降，且其杂散辐射通量与“全黑”遮光罩在温度降低20～30 K的工况相近，但制冷成本与结构复杂度显著降低，为后续低温遮光结构设计提供了参考。更多还原

【Abstract】 Objective To address stray radiation interference during infrared detection of high-temperature targets(approximately 2000 K), traditional baffles, while effective at suppressing stray radiation from both internal and external sources, emit thermal radiation within the mid-to-far infrared band(3-14 μm) that drowns out radiative signals from high-temperature samples, severely compromising detection accuracy; consequently, suppressing the baffle’s own stray radiation becomes a critical bottleneck for improving measurement accuracy of spectral radiation intensity in this band. Current research commonly employs cryogenic optical designs to mitigate thermal radiation impacts from baffles and mechanical structures on infrared measurements, but as cryogenic temperatures decrease, refrigeration mechanisms exhibit progressively declining cooling efficiency alongside exponentially increasing power consumption, leading to substantially elevated cooling costs and heightened structural complexity in cooling systems. Therefore, an urgent need exists for a novel baffle design methodology capable of effectively suppressing the baffle’s intrinsic stray radiation while maintaining its capability to suppress out-of-field stray radiation and significantly reducing refrigeration costs.Methods Based on the baffle configuration parameter framework established in this study, a precise three-dimensional solid model is constructed in the Solid Works software(Fig. 2), with this digital model subsequently imported into the Trace Pro optical simulation platform for high-fidelity ray-tracing computations(Fig. 4); systematic calculation of the point source transmittance(PST) distribution curves under black-painted internal surface conditions quantitatively characterizes this core metric of stray radiation suppression performance, thereby validating the engineering rationality of the baseline configuration. To deepen the analysis of internal stray radiation distribution, the structural benchmark of a single-stage vane is explicitly defined(Fig. 9), with critical emphasis on the functional trade-off: while uniformly applying low-emissivity/low-absorptivity coatings across all internal surfaces reduces self-emitted thermal radiation, it severely compromises the baffle’s fundamental capacity to suppress out-of-field stray radiation. Given this constraint, hierarchical analysis methodology quantifies the contribution weight of each vane stage to total stray radiation flux, establishing dual optimization objectives of minimized stray radiation flux and PST compliance—through multi-parameter iterative computation, the optimal configuration stage count for whitened vanes is determined. Integrating advancements in low-emissivity coating materials, the differential impact of coating emissivity on baffle intrinsic radiation flux(endogenous interference) and out-offield suppression efficacy(functional metric) is rigorously investigated under optimized whitened-stage configurations. Finally, comparative experiments under isothermal conditions directly contrast intrinsic stray radiation flux values between “front black-rear white” and all-black benchmark configurations, while synchronously measuring mid-far infrared noise-to-signal ratio(NSR) improvement margins for 2000 K high-temperature targets—this systematic validation conclusively demonstrates the dual breakthroughs of the “front black-rear white” paradigm: refrigeration system energy consumption reduction(economic advantage) and enhanced infrared spectral detection accuracy for high-temperature targets(technical superiority), fully elucidating the synergistic interaction mechanism among coating emissivity, whitened vane stage configuration, and operational temperature upon baffle stray radiation suppression capability and self-emission characteristics.Results and Discussions Based on Planck’s law, which dictates that an object’s thermal radiation intensity is governed by its emissivity and temperature, suppressing the baffle’s self-emitted stray radiation primarily involves two approaches: substituting traditional black paint with low-infrared-emissivity materials or reducing the baffle’s operational temperature. When geometric parameters such as vane depth, spacing, inclination angle, and facet orientation remain fixed, applying low-emissivity coatings to internal surfaces significantly diminishes stray radiation flux; however, these coatings concurrently weaken out-of-field stray radiation suppression capability due to reduced absorptivity(Fig. 8). Consequently, targeted surface treatment informed by stray radiation flux distribution across hierarchical vanes(Figs. 10 and 11) necessitates the proposed “front black-rear white” configuration—where rear vanes are painted white while front vanes retain highly absorptive/emissive black paint. As white-painted vane stages increase, the baffle’s stray radiation flux exhibits an initial decline followed by stabilization(Fig. 12), whereas its effective stray radiation suppression angle and PST progressively expand(Figs. 13 and 14), markedly degrading suppression performance; analysis of PST and stray radiation flux variation versus whitening stages(Fig. 15) confirms seven stages as the optimal solution for this configuration. Further investigation reveals that fixed whitening stages render coating emissivity influential solely on intrinsic stray radiation flux(Fig. 16), without significantly altering external stray radiation suppression(Fig. 17). Though reducing emissivity from 0.95 to 0.025 decreases flux to only ～50% of baseline versus the theoretically predicted ～20%—attributed to rear-stage whitening reducing flux while compromising front-stage energy absorption attenuation, thereby increasing detector-reaching stray radiation from front vanes and diminishing net flux reduction. Ultimately this design achieves mid-to-far infrared stray radiation flux is approximate to a 20-30 K temperature reduction in all-black configurations(Fig. 18), substantially curtailing optical system cooling costs. Under cryogenic conditions(～200 K), optimized baffles reduce mid-to-far infrared NSR for high-temperature targets by over 90% compared to roomtemperature(293 K) all-black designs, while maintaining merely 50% of the NSR observed in same-temperature all-black configurations(Fig. 19), thereby dramatically enhancing spectral radiation intensity detection accuracy for high-temperature objectives.Conclusions To mitigate interference from the baffle’s own stray radiation on the detection of spectral radiation intensity in the midto-far infrared band for high-temperature targets, this paper proposes a “front black-rear white” baffle design. Through systematic analysis of the influence of whitened vane stages and coating emissivity on both internal and external stray radiation suppression, an optimal configuration of whitened vane stages(7 stages in this study) is identified for engineering applications. This configuration significantly reduces the baffle’s self-emitted radiation flux while maintaining its capability to suppress out-of-field stray radiation. Consequently, the design achieves substantial reductions in baffle cooling costs and self-emitted stray radiation flux, alongside effective preservation of out-of-field suppression performance, thereby dramatically enhancing detection accuracy for spectral radiation intensity of high-temperature targets in the mid-to-far infrared band.更多还原