Quantum terahertz electronics (QTE) using coherent radiation from high temperature superconducting Bi2Sr2CaCu2O8+δ intrinsic Josephson junctions

• An attempt to Quantum Terahertz Electronics (QTE) has been made by improving IJJ characteristics.
• High power THz emission was observed in a stand-alone type of rectangular mesa up to about 30 mW.
• For higher power emission impedance matching between the mesa and vacuum should be realised.
• Strong emission occurs only when the ac-Josephson effect and the cavity resonance work together.

An attempt has been made to improve THz radiation characteristics emitted from mesas made from Bi2Sr2CaCu2O8+δ single crystals in order to achieve an ultimate goal of high frequency quantum device applications, named here as the Quantum Terahertz Electronics (QTE). Among many requirements to be fulfilled and necessary for the development, we here made an effort to generate more intense radiation using a stand-alone type of mesa. Some characteristic features are described.