Increase of the laser radiation frequency (up to λ ~1 nm) by three-photon stimulated scattering

It is proposed to use three-boson stimulated scattering to search for hitherto unobserved effects that should occur when three laser beams of wavelengths λ_1–3 intersect at certain angles. For λ₁=λ₂=1–10 nm and λ₃≥10 μ, the attainable power densities should make it possible in principle to construct a frequency doubler with an efficiency 10^–10–1 %, whereas for λ₁=λ₂<1 nm and λ₃≥1 cm the efficiency should be of the order of 100%.