THz emission from a stacked coherent flux-flow oscillator: non-local radiative boundary conditions and the role of geometrical resonances

Abstract

I derive simple non-local dynamic boundary conditions, suitable for modelling of radiation emission from stacked Josephson junctions, and employ them for analysis of flux-flow emission from intrinsic Josephson junctions in high-$T_c$ superconductors. It is shown that due to the lack of Lorenz contraction of fluxons in stacked junctions, high quality geometrical resonances are prerequisite for high power emission from the stack. This leads to a dual role of the radiative impedance: on the one hand, small impedance increases the efficiency of emission from the stack, on the other hand, enhanced radiative losses reduce the quality factor of geometrical resonances, which may decrease the total emission power. Therefore, the optimal conditions for the coherent flux-flow oscillator are achieved when radiative losses are comparable to resistive losses inside the stack.

4 pages, 2 figures

References in corpus (3)

• Temperature dependence of the bulk energy gap in underdoped Bi-2212: Evidence for the mean-field superconducting transition
• Observation of superluminal geometrical resonances in Bi2Sr2CaCu2O8+x intrinsic Josephson junctions
• Stabilization of in-phase fluxon state by geometrical confinement in small Bi-2212 mesa structures

Cited by in corpus (10)

• THz emission from intrinsic Josephson junctions at zero magnetic field via breather auto-oscillations
• Superconducting THz sources with 12% power efficiency
• Thermal and electromagnetic properties of Bi${}_2$Sr${}_2$CaCu${}_2$O${}_8$ intrinsic Josephson junction stacks studied via one-dimensional coupled sine-Gordon equations
• Direct visualization of phase-locking of large Josephson junction arrays by surface electromagnetic waves
• Observation of polaritons in Bi2Sr2CaCu2O8+x single crystals
• Design aspects of Bi${}_2$Sr${}_2$CaCu${}_2$O${}_{8+\delta }$ THz sources: optimization of thermal and radiative properties
• Terahertz emission from mutually synchronized standalone Bi2Sr2CaCu2O8+x intrinsic-Josephson-junction stacks
• Resonant switching current detector based on underdamped Josephson junctions
• A distributed, active patch antenna model of a Josephson oscillator
• Strong polaritonic interaction between flux-flow and phonon resonances in Bi2Sr2CaCu2O8+x intrinsic Josephson junctions: Angular dependence and the alignment procedure