光学非相干光子互信息
Optically Incoherent Photonic Mutual Information
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中文总结 AI 辅助
研究光学信息传输，引入端到端框架连接波动物理与互信息，建立统一线性信道模型。通过该模型研究表明，相干源和非相干源情况下信息传输特性不同，推导了非相干互信息上界，可用于近场显微镜等多种领域。
中文摘要 AI 辅助
传统光学信息传输评估依赖脱节抽象来连接电磁传播、相干性和通信理论，本文引入端到端框架，直接将严格的亚波长波动物理与香农互信息相连。通过提升麦克斯韦电流到场格林函数来传播二阶场相关性（互强度），建立统一线性信道模型。应用此框架表明，互信息优化的光子前端由可用空间自由度、源统计和检测定律共同决定。对于平方律探测器测量的相干源，探测器数量超过源时，拓扑优化前端从点聚焦转变为干涉混合，互信息超越仅基于幅度的点聚焦基线；对于空间非相干源，信道简化为格林函数的哈达玛平方，各向同性源协方差下，点聚焦在固定弗罗贝尼乌斯范数时唯一最大化互信息，存在源相关性时，优化前端更倾向光学混合。最后推导了可实现的非相干互信息的闭式上界。潜在应用包括近场显微镜、直接检测光数据链路等。
英文摘要
While traditional evaluations of optical information transfer rely on disjointed abstractions to bridge electromagnetic propagation, coherence, and communication theory, we introduce an end-to-end framework that directly connects rigorous subwavelength wave physics to Shannon mutual information. By lifting the Maxwell current-to-field Green's function to propagate second-order field correlations (the mutual intensity), we establish a unified linear channel model that encapsulates coherent communication, phase retrieval, and incoherent imaging. Applying this framework, we demonstrate that the mutual-information-optimized photonic front end is dictated jointly by available spatial degrees of freedom, source statistics, and detection laws. For coherent sources measured by square-law detectors, we identify a structural transition: when detectors outnumber sources, topology-optimized front ends shift from point-focusing to interferometric mixing. This mixing leverages interference cross terms to make relative source phases information-bearing, yielding mutual information that surpasses the point-focusing amplitude-only baseline. Conversely, for spatially incoherent sources, the channel reduces to the Hadamard square of the Green's function. In this regime, under an isotropic source covariance, we prove that point-focusing uniquely maximizes the mutual information at fixed Frobenius norm. Under source correlations, the optimized front ends instead favor optical mixing. Finally, we derive closed-form upper bounds on achievable incoherent mutual information, governed entirely by the coherent singular values of the underlying electromagnetic operator. Potential applications include near-field microscopy, direct-detection optical datalinks, reference-free phase retrieval, fluorescence and thermal imaging, and structure-agnostic benchmarks for end-to-end-designed computational imagers.
