Excitation of oblique surface electromagnetic waves in semibounded layered superconductors by means of the attenuated-total-reflection method

Nowadays a good deal of attention is focused on studies into the properties of surface electromagnetic waves (SEMWs) because they are extensively used in modern electronic devices. Special attention has been given to the SEMWs in semibounded layered superconductors such as Bi₂Sr₂CaCu₂O_8+δ because these structures can sustain well-bounded SEMWs at terahertz frequencies. This remarkable property of the layered superconductors is caused by the strong anisotropy of their conductivity. Indeed, the currents in the a⃗b⃗ plane are hundred times greater than the currents along the c⃗ axis. As a consequence, there are two effective plasma frequencies that differ by two orders of magnitude. One of the frequencies ω_J (the so-called Josephson plasma frequency) is of the order of 10¹² sec^-1 and obeys the condition ħω_J <; 2Δ, where ħ is Planck´s constant, Δ is the superconducting energy gap [1].