Microwave Technology in the Terahertz Region

Electromagnetic waves with frequencies between 0.1 THz and some 10 THz cover the gap from the millimeter wave bands to the infrared optical region. Coherent microwave technology concerning signal generation and detection has been introduced in this THz-region to a steadily growing extent in the past, mainly forced by applications in radioastronomy and remote sensing. The paper tries to review the state of the art of this submillimeter wave technology with emphasis on molecular gas lasers as sources and quasi-optical waveguiding for signal processing.