Generation of higher optical harmonics has recently entered the realm of
subwavelength optics, and it has been achieved in gratings and metasurfaces.
Here, we demonstrate the source of high-harmonic generation scaled down to a
subwavelength dielectric resonator. We study fifth and seventh optical
harmonics generated from an AlGaAs resonator designed to support a bound state
in the continuum. Higher optical harmonics can serve as a source of radiation
in unconventional spectral ranges, such as the extreme-UV, and our work paves
the way to the light sources with subwavelength volumes.Comment: 2 figures, 3 pages, to be publishe