Design of a high-power terahertz emitter array using a high-temperature superconductor

By applying a dc voltage V across the stack of intrinsic Josephson junctions naturally present in the high-temperature superconductor Bi₂Sr₂CaCu₂O_8+d (Bi2212), several groups have been able to obtain coherent THz emission at output powers in the µW range. To enhance the output power well into the mW range suitable for many applications, we have studied a compact design of a stand-alone (Au-Bi2212-Au) mesa array. In this design, an array of 12 stand-alone mesas consisting of 6 identical interior pie-shaped wedge mesas and 6 identical exterior slitted annular mesas, all produced from an original stand-alone disk mesa of radius ρ_o by one circular cut at radius ρ_i< ρ_o and three linear cuts through their center all mutually rotated by 60 degrees. We studied the cavity mode frequencies of the pie-shaped and slitted annular mesas with various ρ_{i /} ρ_o ratios, in order to obtain a set of several matching cavity mode frequencies of the two different mesa shapes. The matching wave functions for the two mesa shapes and the predictions for the angular distributions of the high-power output THz emission will be presented.