Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E.v.

Dennis Stanze

Bernd Sartorius

Helmut Roehle

Roman J Dietz

Roman Dietz

A material may be identified using THz radiation that simultaneously or sequentially includes at least one first frequency portion and a second frequency portion different therefrom. An object formed from the material to be identified is irradiated with the THz radiation and the THz radiation exiting the object is detected using a phase-sensitive THz receiver. A time or phase offset, caused by the object, is measured at least for the first frequency portion and a material thickness is determined therefrom. Attenuation of the received signal, at least for the second frequency portion, is determined. An absorption coefficient for at least the second frequency portion is calculated using the material thickness.

Method and device for identifying a material

A terahertz system can be configured for producing and coherently detecting terahertz radiation. The system can comprise a laser light source and two THz antennas, a first of which is used as a transmission antenna and a second of which is used as a receiver antenna, which are each optically coupled to the laser light source by an optical fiber and can be activated by light from this laser light source, wherein the THz antennas each have a semiconductor chip to which antenna conductors have been contact-connected and which comprises at least one photosensitive active layer with a band edge wavelength which is longer than a wavelength of the laser light source and at least one layer, adjoining the active layer, with a band edge wavelength which is shorter than the wavelength of the laser light source, wherein the band edge wavelength of the active layer of at least one of the THz antennas is at least 200 nm longer than the wavelength of the laser light source.

Improved-efficiency fibre-coupled terahertz system

The invention relates to a system for producing a signal having a variably adjustable time position or phase position, comprising at least one light source for producing a first light component () having a first wavelength and a second light component (') having a second wavelength deviating from the first wavelength and a phase modulator () for varying a phase of the first light component (), wherein the system is designed to produce a beat note signal by superposing the two light components (&#x2032;) and has a common optical fiber () for coupling in both light components (&#x2032;), wherein furthermore the phase modulator () is arranged at an end or in the course of said optical fiber () and is transparent to both light components (&#x2032;) and is designed to vary the phase of the first light component () selectively independently of a phase of the second light component (&#x2032;) or more intensely than the phase of the second light component (&#x2032;). The invention further relates to a use of such a system.

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Berlin, Germany

Dennis Stanze