  We demonstrate a method to image an object using a self-probing approach
based on semiconductor high-harmonic generation. On one hand, ptychography
enables high-resolution imaging from the coherent light diffracted by an
object. On the other hand, high-harmonic generation from crystals is emerging
as a new source of extreme-ultraviolet ultrafast coherent light. We combine
these two techniques by performing ptychography measurements with
nano-patterned crystals serving as the object as well as the generation medium
of the harmonics. We demonstrate that this strong field in situ approach can
provide structural information about the object. With the future developments
of crystal high harmonics as a compact short-wavelength light source, our
demonstration can be an innovative approach for nanoscale imaging of photonic
and electronic devices in research and industry.
