High-efficiency contact grating fabricated on the basis of a Fabry–Perot type resonator for terahertz wave generation

We have designed and fabricated a contact grating device to increase diffraction efficiency on the basis of the principle of the Fabry–Perot resonator. The grating structure and layer thicknesses were carefully determined by considering the electric field strength in the device and the fabrication accuracy of the grating. The prototype device had a peak diffraction efficiency of 71% at an incident angle of 42°; these values were slightly different from the design values of 78% and 44.5°, respectively. Numerical calculations revealed that this deviation was caused by the fabricated grating structure. A higher terahertz power will be expected with a device as per the design.