Phase-matched sum frequency generation of antiferromagnetic film in THz frequency field

We report on a way to obtain a new source in THz frequency field based on sum frequency (SF) generation of an antiferromagnetic film (AFF). The continuous SF output windows versus the infrared signal wave frequencies are shown. We found that the highest SF outputs can be induced when the frequencies of the two signal waves are both situated at the vicinity of the same resonant frequency of AFF. In addition, the incident angles are in the smaller angle regions. An optimum interact length is defined which should be necessary for the choice of AFF thickness in the experiments. Finally, the frequencies of highest SF outputs can be modulated by controlling the external magnetic field strength.