<p>Microstructures&nbsp;are widely used in the manufacture of functional surfaces, which have&nbsp;potential applications in antireflective thin films, microfluidics systems, and so on. An optical-based super-resolution, non-invasive method is preferred for the inspection of surfaces with massive microstructures. The Structured Illumination Microscopy (SIM) uses standing-wave illumination to reach optical super-resolution. Recently, coherent SIM is being studied. It can obtain not only the super-resolved intensity distribution but also the phase and amplitude distribution of the sample surface beyond the diffraction limit. By analysis of the phase-depth dependency, the depth measurement for microgroove structures with coherent SIM is expected. FDTD analysis is applied for observing the near-field response of microgroove under the standing-wave illumination. The near-field phase shows depth dependency in this analysis. Moreover, the effects from microgroove width, the incident angle, and the relative position between the standing-wave peak and center of the microgroove are investigated. It is found the near-field phase change can measure depth until 200 nm (aspect ratio 1) with an error of up to 20.4 nm in the case that the microgroove width is smaller than half of the wavelength. And the results suggest that adding one more peak shift of standing-wave illumination can avoid problems caused by the low intensity at&nbsp;the standing-wave node&nbsp;to&nbsp;allow&nbsp;the realization of the coherent SIM.</p>

The Fdtd Analysis of Near-Field Response for Microgroove Structure With Standing Wave Illumination for the Realization of Coherent Structured Illumination Microscopy

Paper Proceedings: https://asmedigitalcollection.asme.org/MSEC/MSEC2021/volume/85062

2021 International Manufacturing Science and Engineering Conference (MSEC2021)

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