Beat Signal Generating Device for Use in a Terahertz System, Terahertz System and Use of a Beat Signal Generating Device

The invention relates to a beat signal generating device for use in a Terahertz system, comprising - a first monomode laser (2) for generating radiation of a first wavelength ( 1 ); - a second monomode laser (3) for generating radiation of a second wavelength ( 2 ) different from the first wavelength ( 1 ); - a first and a second output port (11, 12); - a phase modulating unit (4) for modifying both the phase of radiation generated by the first laser (2) and the phase of radiation generated the second laser (3), wherein the beat signal generating device (1) is configured in such a way that - the radiation generated by the first laser (2) is transmitted through the second laser (3) and superposed with the radiation generated by the second laser (2) at the second output port (12), and - the radiation generated by the second laser (3) is transmitted through the first laser (2) and superposed with the radiation generated by the first laser (2) at the first output port (11), such that a first beat signal (A) will be emitted at the first output port (11) and a second beat signal (B) will be emitted at the second output port (12), wherein the phase between the first and the second beat signal (A, B); can be adjusted by means of the phase modulating unit (4). The invention also relates to a Terahertz system and the use of a beat signal generating device.