Caustic imaging of gallium droplets using mirror electron microscopy

Shane Kennedy, Changxi Zheng, Wen-Xin Tang, David Paganin, David Jesson

    Research output: Contribution to journalArticleResearchpeer-review

    25 Citations (Scopus)


    We discuss a new interpretation of mirror electron microscopy (MEM) images, whereby electric field distortions caused by surface topography and/or potential variations are sufficiently large to create caustics in the image contrast. Using a ray-based trajectory method, we consider how a family of rays overlaps to create caustics in the vicinity of the imaging plane of the magnetic objective lens. Such image caustics contain useful information on the surface topography and/or potential, and can be directly related to surface features. Specifically we show how a through-focus series of MEM images can be used to extract the contact angle of a Ga droplet on a GaAs (001) surface.
    Original languageEnglish
    Pages (from-to)356 - 363
    Number of pages8
    Issue number5
    Publication statusPublished - 2011

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