A similar question has been asked, and to some extent the answer is: you need an antenna with $L \approx 200nm$. But it's not entirely clear to me if this is completely hypothetical, as "Marek" also says:
Yes, if you heat it :) But assuming you want to use it in the usual way the answer is no.
How does the creation of X-ray waves and Microwaves differ from the creation of Radiowaves? (if it does)
Would (and I don't know to what extent this is hypothetical) the creation of electromagnetic waves with a wavelength between $400nm$ and $700nm$ (same visible light) actually produce light? (i guess as in: 'would these field disturbances yield photons?')