Marbach Sébastien, Claveau Rémy, Montgomery Paul, Flury Manuel
ICube, Université de Strasbourg, CNRS, INSA, 67000, Strasbourg, France.
Sci Rep. 2024 Nov 6;14(1):26974. doi: 10.1038/s41598-024-77162-7.
The characterisation of novel materials presents a challenge that requires new and original developments. To face some of these demands for making measurements at the nanoscale, a new microsphere-assisted white light interference nanoscope performing local reflectance mapping is presented. This technique presents the advantages of being non-destructive, full-field and label-free. A 145 μm diameter microsphere, glued to the end of an optical fiber, is inserted inside the white light interference microscope to improve the lateral resolution from 940 nm to 520 nm. The acquisition and the Fourier transform processing of a stack of interference images superimposed on the virtual image produced by the microsphere allows the extraction of the local reflectance over a wavelength range of 460 nm to 900 nm and a field of view of 8 μm in diameter. The enhancement in the lateral resolution of the reflectance is demonstrated through the spectral distinction of neighboring ripples on a laser-textured colored stainless-steel sample that cannot be resolved without the microsphere, on regions with a surface of 279 × 279 nm horizontally spaced 279 nm apart. Future improvements could potentially lead to a lateral resolution of reflectance measurement over a 100 nm diameter area in air, paving the way to sub-diffraction reflectance mapping.
新型材料的表征带来了一项挑战，这需要全新的原创性进展。为了满足在纳米尺度进行测量的部分需求，本文提出了一种新型的微球辅助白光干涉纳米显微镜，它能够进行局部反射率映射。该技术具有无损、全场和无标记的优点。将一个直径为145μm的微球粘贴在光纤末端，插入白光干涉显微镜内部，可将横向分辨率从940nm提高到520nm。对叠加在微球产生的虚拟图像上的干涉图像堆栈进行采集和傅里叶变换处理，能够在460nm至900nm的波长范围内以及直径为8μm的视场中提取局部反射率。通过对激光纹理彩色不锈钢样品上相邻波纹的光谱区分，证明了反射率横向分辨率的提高。在水平间距为279nm、面积为279×279nm的区域，如果没有微球，这些波纹是无法分辨的。未来的改进可能会使空气中直径为100nm区域的反射率测量横向分辨率得到提升，为亚衍射反射率映射铺平道路。
