Surface plasmon resonance microscopy (SPRM) has been massively applied for near-field optical measurement, sensing, and imaging because of its high detection sensitivity, nondestructive, noninvasive, wide-field, and label-free imaging capabilities. However, the transverse propagation characteristic of the surface plasmon wave generated during surface plasmon resonance (SPR) leads to notable “tail” patterns in the SPR image, which severely deteriorates the image quality. Here, we propose an incidence angle scanning method in SPRM to obtain a resonance angle image with exceptional contrast that significantly mitigates the adverse effects of “tail” patterns. The resonance angle image provides the complete morphology of the analyzed samples and enables two-dimensional quantification, which is incapable in conventional SPRM. The effectiveness of the method was experimentally verified using photoresist square samples with different sizes and two-dimensional materials with various geometric shapes. The edges of samples were fully reconstructed and a maximum fivefold increase in the image contrast has been achieved. Our method offers a convenient way to enhance the SPRM imaging capabilities with low cost and stable performance, which greatly expands the applications of SPRM in label-free detection, imaging, and quantification.

中文翻译：

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灵活的入射角扫描表面等离子共振显微镜，用于具有增强对比度的形态检测


表面等离子体共振显微镜（SPRM）因其高检测灵敏度、无损、非侵入、宽视场和无标记成像能力而被广泛应用于近场光学测量、传感和成像。然而，表面等离子体共振（SPR）过程中产生的表面等离子体波的横向传播特性导致SPR图像中出现明显的“拖尾”图案，严重恶化了图像质量。在这里，我们提出了一种 SPRM 中的入射角扫描方法，以获得具有出色对比度的共振角图像，从而显着减轻“尾部”图案的不利影响。共振角图像提供了分析样品的完整形态，并实现了二维定量，这是传统 SPRM 所无法实现的。利用不同尺寸的光刻胶方形样品和各种几何形状的二维材料实验验证了该方法的有效性。样本的边缘被完全重建，并且图像对比度最大增加了五倍。我们的方法提供了一种低成本、性能稳定的增强SPRM成像能力的简便方法，极大地扩展了SPRM在无标记检测、成像和定量方面的应用。