Resonant-second-harmonic generation of laser radiation in a semiconductor

A high-power laser radiation, with frequency ω₁ and wave vector k₁z^, propagating through a semiconductor produces a second-harmonic longitudinal current at 2ω₁ and 2k₁z^. When a wiggler magnetic field (0,k₀z^) is simultaneously present in the system, the J×{}B force on the electrons produces a transverse second harmonic current at 2ω₁ and (2k₁+k₀)z^, driving second-harmonic electromagnetic radiation. For a specific value of wiggler wave number k₀=k0c the phase-matching conditions for the process are satisfied, leading to resonant enhancement in the efficiency of energy conversion. k0c decreases with the frequency ω₁ of the laser.