(Invited) Terahertz emission from the intrinsic Josephson junctions of high-symmetry thermally-managed BSCCO microstrip antennas

We study the coherent terahertz emission from the intrinsic Josephson junctions in thermally-managed, high-symmetry, thin microstrip antennas constructed from single crystals of the highly two-dimensional, layered high-temperature superconductor BSCCO. The thin antennas studied are disk [1,2], square [3], and equilateral triangular [4,5] in shape. Upon application of a dc voltage across the junctions, the primary radiation source is the uniform ac Josephson current, but when the appropriate point in the current-voltage characteristics is found, the excitation of an electromagnetic cavity mode can lead to a considerable enhancement of the output power. When properly thermally managed by covering the top and bottom of a thin BSCCO crystallite with Au and sandwiching that between sapphire plates[6], only the one-dimensional representation wave functions of the appropriate point groups are excited, and the world record 2.4 THz emission from a superconductor was recently observed [2] from such a device. The coherent emission is widely tunable and has a narrow linewidth. The angular distributions of the output power are calculated and compared with experiment. [1] M. Tsujimoto et al., Phys. Rev. Lett. 105, 037005 (2010). [2] T. Kashiwagi et al., Appl. Phys. Lett. 107, 082601 (2015). [3] R. A. Klemm et al., IEEE JSTQE (2017, in press). [4] D. P. Cerkoney et al., J. Phys.: Condens. Matter 29, 015601 (2017). [5] K. Delfanazari et al., Opt. Express 21, 2171 (2013). [6] T. Kashiwagi et al., Phys. Rev. Applied 4, 054018 (2015).