Transition metal dichalcogenide semiconductors represent elementary components of layered heterostructures for emergent technologies beyond conventional optoelectronics. In their monolayer form they host electrons with quantized circular motion and associated valley polarization and valley coherence as key elements of opto-valleytronic functionality. Here, we introduce two-dimensional polarimetry as means of direct imaging of the valley pseudospin degree of freedom in monolayer transition metal dichalcogenides. Using MoS₂ as a representative material with valley-selective optical transitions, we establish quantitative image analysis for polarimetric maps of extended crystals, and identify valley polarization and valley coherence as sensitive probes of crystalline disorder. Moreover, we find site-dependent thermal and non-thermal regimes of valley-polarized excitons in perpendicular magnetic fields. Finally, we demonstrate the potential of wide-field polarimetry for rapid inspection of opto-valleytronic devices based on atomically thin semiconductors and heterostructures.

过渡金属二硫化氢半导体代表了超越常规光电技术的新兴技术的层状异质结构的基本组成部分。它们以单层形式容纳具有定量圆周运动以及相关的谷底极化和谷底相干性的电子，这些电子是光电电子功能的关键要素。在这里，我们介绍二维极化仪，作为对单层过渡金属二卤化硅谷中伪自旋谷的自由度进行直接成像的手段。使用MoS ₂作为具有谷选择性光学跃迁的代表性材料，我们建立了扩展晶体的极化图的定量图像分析，并将谷极化和谷相干性确定为晶体无序的敏感探针。此外，我们发现在垂直磁场中谷极化激子的位置相关的热和非热态。最后，我们演示了基于原子薄半导体和异质结构的广域极化技术在快速检查光电电子设备中的潜力。