Abstract

We propose a scheme for generation of a continuous-wave THz radiation, based on a nonlinear interaction of three electromagnetic (e.m.) waves in atomic media with a Λ configuration of levels, where the frequency of a transition between two lower metastable states |1> and |2> is in the THz range and transitions |1> - |3> and |2> - |3> to the upper state are driven by optical fields. Such systems can be found, e.g., in alkaline-earth atoms where the states |1> = ³P₀ or ³P₂, |2> = ³P₁ and |3> = ³S₁, in samarium atoms |1> = 4f⁶6s²⁷F₀, |2> = 4f⁶6S²⁷F₁ in Al and other atoms, where the THz transition is usually between the two fine structure components, and probably in some molecules and doped crystals as well.

© 2000 IEEE