THz systems are promising tools for non-destructive testing and material characterisation. High costs, which are mostly determined by the laser system, prevent the application in the market. By using monolithic dual-colour lasers, a significant cost decrease can be achieved. We discuss some of the typical drawbacks associated with these lasers. Furthermore, we present a complete THz system which is based on a dual-colour diode laser to show the capabilities for material characterisation.

The paper shows the determination and application of the generalized efficiency of waveguide thermoelectric power sensor and the uncertainty in the direct transfer system to establish measurement traceability of the millimeter wave power to the primary standard. The waveguide thermoelectric sensor with its generalized efficiency can be used as a transfer standard to calibrate all types of power sensors to determine both the generalized efficiency and the calibration factor.