Is there laser operating at megahertz?

Question

I have tried to find a laser with working frequency at megahertz by Google but failed. Is there exist one?

Answer 1

Given the frequency range, it cannot be called laser (light amplification via stimulated emission of radiation), since the frequency is not in the optical range (see electromagnetic spectrum)... it can even hardly be called maser (microwave amplification via stimulated emission of radiation), since it is not in the microwave range... so the best would be to google for radio frequency amplification via stimulated emission or quantum generator of radio waves or something like that.

Related:
Quantum description of radio antenna
Does a radio receiver "collapse" a radio wave function?

Remark:
The way I understand the question is that we are talking not simply about absorption and emission of radio frequency photons on a quantum level, but about a laser-like devices - i.e., amplification of these photons via stimulated emission and possibly also their emission as a free field. Already in microwave range, the small frequency of the photons (compared to room temperature) requires using cryogenic technology and confining photons to waveguides (possibly superconducting waveguides.) See, e.g., The bright side of Coulomb blockade.