Cavity mode enhancement of terahertz emission from equilateral triangular microstrip antennas of the high-TcT_c superconductor Bi2_2Sr2_2CaCu2_2O8+δ_{8 + δ}

We study the transverse magnetic (TM) electromagnetic cavity mode wave functions for an ideal equilateral triangular microstrip antenna (MSA) exhibiting $C_{3v}$ point group symmetry. When the $C_{3v}$ operations are imposed upon the antenna, the TM($m,n$) modes with wave vectors $\alpha \sqrt[ ]{m^2 + nm + n^2}$ are much less dense than commonly thought. The $R_3$ operations restrict the integral $n$ and $m$ to satisfy $\mid m - n \mid$ = 3$p$, where $p \geq$ 0 and $p \geq$ 1 for the modes even and odd under reflections about the three mirror planes, respectively. We calculate the forms of representative wave functions and the angular dependence of the output power when these modes are excited by the uniform and non-uniform ac Josephson current sources in thin, ideally equilateral triangular MSAs employing the intrinsic Josephson junctions in the high transition temperature $T_c$ superconductor Bi$_2$Sr$_2$CaCu$_2$O$_{8 + \delta}$, and fit the emissions data from an earlier sample for which the $C_{3v}$ symmetry was apparently broken.UCF RAMP program, JSPS Research Fellowship for young scientists, CREST-JST (Japan Science and Technology Agency), WPI (World Premier International Research Center Initiative)- MANA (Materials Nanoarchitectonics) project (NIMS

Cavity mode enhancement of terahertz emission from equilateral triangular microstrip antennas of the high-TcT_c superconductor Bi2_2Sr2_2CaCu2_2O8+δ_{8 + δ}

We study the transverse magnetic (TM) electromagnetic cavity mode wave functions for an ideal equilateral triangular microstrip antenna (MSA) exhibiting $C_{3v}$ point group symmetry. When the $C_{3v}$ operations are imposed upon the antenna, the TM($m,n$) modes with wave vectors $\alpha \sqrt[ ]{m^2 + nm + n^2}$ are much less dense than commonly thought. The $R_3$ operations restrict the integral $n$ and $m$ to satisfy $\mid m - n \mid$ = 3$p$, where $p \geq$ 0 and $p \geq$ 1 for the modes even and odd under reflections about the three mirror planes, respectively. We calculate the forms of representative wave functions and the angular dependence of the output power when these modes are excited by the uniform and non-uniform ac Josephson current sources in thin, ideally equilateral triangular MSAs employing the intrinsic Josephson junctions in the high transition temperature $T_c$ superconductor Bi$_2$Sr$_2$CaCu$_2$O$_{8 + \delta}$, and fit the emissions data from an earlier sample for which the $C_{3v}$ symmetry was apparently broken.UCF RAMP program, JSPS Research Fellowship for young scientists, CREST-JST (Japan Science and Technology Agency), WPI (World Premier International Research Center Initiative)- MANA (Materials Nanoarchitectonics) project (NIMS

Cavity modes in broadly tunable superconducting coherent terahertz sources

© 2019 Published under licence by IOP Publishing Ltd. We discuss the cavity modes and radiation pattern in solid state terahertz (THz) sources based on layered high-temperature superconducting Bi2Sr2CaCu2O8+δ (Bi-2212). We experimentally measure the emission spectra using the Fourier transform infrared spectrometer in order to elucidate the radiation mechanism of the mesa samples. Moreover, we experimentally study the angular dependence of the emission intensity obtained in one mesa's plane at the frequency f = 0.61 THz, at various detection angles θ by rotating the sample holder relative to the detector, to identify the excited EM cavity modes within the mesa that participate in the device output power enhancement. We modelled the mesa cavity and find a relatively good agreement between the experiment and theory. Our results show that compact, coherent and continuous-wave Bi-2212 THz devices are one of the most promising THz sources, capable of bridging the microwaves to photonics gap