Modeling the electromagnetic cavity mode contributions to the THz emission from triangular Bi2Sr2CaCu2O8+δ mesas

In order to understand the radiation observed from the intrinsic Josephson junctions in triangular Bi2Sr2-CaCu2O8+delta mesas, we calculate the transverse magnetic (TM) electromagnetic modes for thin equilateral cavities. A new set of distinct but degenerate TM modes coexists with the known modes of Helszajn and James, but are expected to lead to distinct radiation angular distribution patterns. Although we have been unable to solve for the exact TM modes of a thin cavity of general acute isosceles triangular shape, we solved exactly the closely related problems of the TM cavity modes of two thin circumscribing pie-shaped wedges, which provide highly accurate approximations to very acute isosceles triangular cavities. (C) 2012 Elsevier B.V. All rights reserved.