A frequency conversion device and method is disclosed. In one aspect, a frequency device includes an array of mutually spaced semiconductor islands composed of at least one III-V semiconductor compound. The semiconductor islands are configured so that electromagnetic radiation of a first wavelength incident upon the semiconductor islands causes them to emit electromagnetic radiation of a second wavelength shorter than the first wavelength by a nonlinear frequency conversion process. The frequency device further includes a transparent support supporting the semiconductor islands. The transparent support is substantially transparent to radiation of the second wavelength, so that at least the radiation of the second wavelength passes through the transparent support.