AI 中文总结
该研究通过二维相干光谱（2DCS）发现单层过渡金属二硫化物中激子的表观非均匀展宽依赖于激发强度，揭示了对角线线宽通量依赖性源于非均匀饱和，成果对解释激子线宽、衡量样品质量有重要意义。
AI 中文摘要
我们观察到，通过二维相干光谱（2DCS）测量得到的过渡金属二硫化物单层中激子共振的表观非均匀展宽依赖于激发强度。2DCS的关键优势在于能将主要贡献于对角线线宽的非均匀展宽，与主导交叉对角线线宽的均匀展宽分离开。我们发现，对角线线宽的通量依赖性源于有效饱和通量随激子共振能量变化，即非均匀饱和。这些结果对解释激子线宽至关重要，而激子线宽常被用作样品质量的衡量指标。
英文摘要
We observe that the apparent inhomogeneous broadening, as measured by two-dimensional coherent spectroscopy (2DCS), of the exciton resonance in transition-metal dichalcogenide monolayers depends on the excitation strength. A key strength of 2DCS is the ability to separate inhomogeneous broadening, which primarily contributes to the diagonal linewidth, from homogeneous broadening, which dominates the cross-diagonal linewidth. We show that the fluence dependence of the diagonal linewidth arises from the effective saturation fluence varying with the exciton's resonance energy, i.e., inhomogeneous saturation. These results are critical for interpreting the exciton linewidths, which are often used as a measure of sample quality.
