Recent theories proposed a deep revision of the well-known expression for the Purcell factor, with counterintuitive effects, such as complex modal volumes and non-Lorentzian local density of states. We experimentally demonstrate these predictions in tailored coupled cavities on photonic crystal slabs with relatively low optical losses. Near-field hyperspectral imaging of quantum dot photoluminescence is proved to be a direct tool for measuring the line shape of the local density of states. The experimental results clearly evidence non-Lorentzian character, in perfect agreement with numerical and theoretical predictions. Spatial maps with deep subwavelength resolution of the real and imaginary parts of the complex mode volumes are presented. The generality of these results is confirmed by an additional set of far-field and time-resolved experiments in cavities with larger modal volume and higher quality factors.

中文翻译：

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近场和远场发射探测耦合光子晶体腔中状态的非洛伦兹局部密度

最近的理论提出了对珀塞尔因子的著名表达的深刻修正，具有反直觉的影响，例如复杂的模态体积和非洛伦兹局部态密度。我们在具有相对较低光学损耗的光子晶体平板上的定制耦合腔中实验性地证明了这些预测。量子点光致发光的近场高光谱成像被证明是测量状态局部密度线形的直接工具。实验结果清楚地证明了非洛伦兹特性，与数值和理论预测完全吻合。呈现了具有复杂模式体积的实部和虚部的深亚波长分辨率的空间图。