Contact grating device with Fabry-Perot resonator toward intense THz pulse generation by optical rectification

A novel design for a contact grating device with an incorporated Fabry-Perot resonator is proposed for high-power terahertz light (THz) generation. We deposited a multilayer consisting of Ta₂O₅ and Al₂O₃ on a magnesium-doped stoichiometric LiNbO₃ substrate and fabricated grating grooves on the outermost layer. The multilayer was designed such that conditions for a Fabry-Perot resonator were satisfied for light diffracted by the grating. Consequently, the diffraction efficiency was enhanced by the resonator. The diffraction efficiency of the fabricated device was 77%. THz light generation was also demonstrated with the contact grating device.