Abstract: An optical assembly for optical signal processing including a first input for coupling in a first light signal; a second input for coupling in a second light signal; a first beam splitter for splitting the first light signal into a first part and a second part; a second beam splitter for splitting the second light signal into a first part and a second part; a superposing unit; a detector; an electronic signal processing unit; at least one actuating unit; and a delay line for generating a delay of the running time of the first part of the first light signal and of the first part of the second light signal up to the superposing unit. The delay line is configured such that the first part of the first light signal and the first part of the second light signal pass through the delay line in opposite directions.

Abstract: An optical assembly for optical signal processing: including a first input for coupling in a first light signal; a second input for coupling in a second light signal; a first beam splitter for splitting the first light signal into a first part and a second part; a second beam splitter for splitting the second light signal into a first part and a second part; a superposing unit; a detector; an electronic signal processing unit; at least one actuating unit; and a delay line for generating a delay of the running time of the first part of the first light signal and of the first part of the second light signal up to the superposing unit. The delay line is configured such that the first part of the first light signal and the first part of the second light signal pass through the delay line in opposite directions.

Abstract: The invention relates to a method for determining the relative temporal position of electromagnetic pulses. Said method having the steps generating a sequence of first electromagnetic pulses, generating a sequence of second electromagnetic pulses, overlaying at least a part of the first and the second pulses in a saturable absorber, detecting the second pulses that have passed through the saturable absorber by means of a detector in such a manner that the second pulses, but not the first pulses that have passed through the saturable absorber, are detected, and determining the temporal position of the first pulses relative to the temporal position of the second pulses with the aid of a signal from the detector which is generated when the second pulses that have passed through the saturable absorber are received.

Abstract: The invention relates to a method for determining a liquid in a closed container using THz radiation, in which a first and a second measurement are carried out, wherein the THz radiation is emitted in the direction of the liquid for measuring properties of the liquid, and a portion of the THz radiation coming from the direction of the liquid is detected. In the proposed method, the closed container contains, in addition to the liquid, a gas, wherein a wall of the container is transmissive for THz radiation and wherein the detected portion of the THz radiation in the first measurement is reflected at a boundary surface between the wall and the gas or a pocket containing the gas, and the second measurement is reflected at a boundary surface between the wall and the liquid. The first measurement thus serves as a reference measurement for capturing disturbing losses in the THz beam path and for determining influences of the wall on a measurement result for the second measurement.

Abstract: A photoconductor comprising a layer stack with a semiconductor layer photoconductive for a predetermined wavelength range between two semiconductor boundary layers with a larger band gap than the photoconductive semiconductor layer on a substrate, wherein the semiconductor boundary layers comprise deep impurities for trapping and recombining free charge carriers from the photoconductive semiconductor layer, and two electrodes connected to the photoconductive semiconductor layer, for lateral current flow between the electrodes through the photoconductive semiconductor layer.

Abstract: The invention relates to a method for determining the relative temporal position of electromagnetic pulses. Said method having the steps generating a sequence of first electromagnetic pulses, generating a sequence of second electromagnetic pulses, overlaying at least a part of the first and the second pulses in a saturable absorber, detecting the second pulses that have passed through the saturable absorber by means of a detector in such a manner that the second pulses, but not the first pulses that have passed through the saturable absorber, are detected, and determining the temporal position of the first pulses relative to the temporal position of the second pulses with the aid of a signal from the detector which is generated when the second pulses that have passed through the saturable absorber are received.

Abstract: 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.

Abstract: A photoconductor comprising a layer stack with a semiconductor layer photoconductive for a predetermined wavelength range between two semiconductor boundary layers with a larger band gap than the photoconductive semiconductor layer on a substrate, wherein the semiconductor boundary layers comprise deep impurities for trapping and recombining free charge carriers from the photoconductive semiconductor layer, and two electrodes connected to the photoconductive semiconductor layer, for lateral current flow between the electrodes through the photoconductive semiconductor layer.

Abstract: 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.

Abstract: 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 (2) having a first wavelength and a second light component (2?) having a second wavelength deviating from the first wavelength and a phase modulator (5) for varying a phase of the first light component (2), wherein the system is designed to produce a beat note signal by superposing the two light components (2, 2?) and has a common optical fiber (4) for coupling in both light components (2, 2?), wherein furthermore the phase modulator (5) is arranged at an end or in the course of said optical fiber (4) and is transparent to both light components (2, 2?) and is designed to vary the phase of the first light component (2) selectively independently of a phase of the second light component (2?) or more intensely than the phase of the second light component (2?). The invention further relates to a use of such a system.

Abstract: The present invention relates to a device for creating and coherently detecting terahertz radiation, comprising a laser light source (1), a transmission antenna (2) that can be activated by the laser light source (1) for creating the terahertz radiation, and a receiver with a receiver antenna (3) that can be activated by the same laser light source (1), wherein the transmission antenna (2) comprises a photo diode as a light-sensitive element and the receiver antenna (3) a fast photo-conductor as a light-sensitive element. The invention further relates to a use of such a device for analyzing a sample.

Abstract: The invention relates to a method for determining a liquid in a closed container using THz radiation, in which a first and a second measurement are carried out, wherein the THz radiation is emitted in the direction of the liquid for measuring properties of the liquid, and a portion of the THz radiation coming from the direction of the liquid is detected. In the proposed method, the closed container contains, in addition to the liquid, a gas, wherein a wall of the container is transmissive for THz radiation and wherein the detected portion of the THz radiation in the first measurement is reflected at a boundary surface between the wall and the gas or a pocket containing the gas, and in-the second measurement is reflected at a boundary surface between the wall and the liquid. The first measurement thus serves as a reference measurement for capturing disturbing losses in the THz beam path and for determining influences of the wall on a measurement result for the second measurement.

Abstract: 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 fibre 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.

Abstract: Time-domain measurements are carried out using arrangements and methods. A transmitter generates electro-magnetic pulses upon receipt of pulses of an optical pulse source. A coherent detector detects the electro-magnetic pulses or an evoked electro-magnetic signal. A delay line periodically changes the optical path length between the optical pulse source and the coherent detector and/or the electro-magnetic transmitter by periodically moving an optical element of the delay line. A position sensor determines the position of the optical element and smoothes the data generated by the position sensor. The coherent detector detects the electro-magnetic signal evoked by the electro-magnetic pulses. Pulses of the optical pulse source trigger the coherent detector.

Abstract: A beat signal generating device including first and second monomode lasers for generating radiation of a first and second wavelengths respectively; a first and a second output port; a phase modulating unit for modifying both the phase of radiation generated by both the first laser and second laser, wherein radiation generated by the first laser is transmitted through the second laser and superposed with the radiation generated by the second laser at the second output port, and the radiation generated by the second laser is transmitted through the first laser and superposed with the radiation generated by the first laser at the first output port, such that a first beat signal will be emitted at the first output port and a second beat signal will be emitted at the second output port, wherein the phase between the beat signals can be adjusted by means of the phase modulating unit.

Abstract: 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 (2) having a first wavelength and a second light component (2?) having a second wavelength deviating from the first wavelength and a phase modulator (5) for varying a phase of the first light component (2), wherein the system is designed to produce a beat note signal by superposing the two light components (2, 2?) and has a common optical fiber (4) for coupling in both light components (2, 2?), wherein furthermore the phase modulator (5) is arranged at an end or in the course of said optical fiber (4) and is transparent to both light components (2, 2?) and is designed to vary the phase of the first light component (2) selectively independently of a phase of the second light component (2?) or more intensely than the phase of the second light component (2?). The invention further relates to a use of such a system.

Abstract: 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.

Abstract: An inexpensive and compact arrangement for the electrical control and fast modulation of THz transmitters and THz measuring systems is proposed, wherein said arrangement is stable, requires no mechanical movements and operates with a purely electric control, consumes little power and also has a high speed potential for the phase modulation. This is achieved by replacing the components known from the state of the art, namely two lasers, the beam splitters, the couplers and the mechanically moved delay line, with a compact monolithic or hybrid integrated chip (10), particularly a so-called optical master chip without moving parts that comprises at least the two lasers (1, 2), the beam splitters (S3.1, S3.2), the couplers (K3.1, K3.2) and a phase modulator (4.1) for one of the laser waves such that the two generated beat signals are respectively delivered to different chip outputs (6, 7) in order to separately control the THz transmitter and the local oscillator.

Abstract: A photoconductor having a layer stack (72) with a semiconductor layer (64) photoconductive for a predetermined wavelength range between two semiconductor boundary layers (62) with a larger band gap than the photoconductive semiconductor layer (64) on a substrate (60), wherein the semiconductor boundary layers (62) have deep impurities for trapping and recombining free charge carriers from the photoconductive semiconductor layer (64), and two electrodes connected to the photoconductive semiconductor layer (64), for lateral current flow between the electrodes through the photoconductive semiconductor layer (64).

Abstract: The present invention relates to a device for creating and coherently detecting terahertz radiation, comprising a laser light source (1), a transmission antenna (2) that can be activated by the laser light source (1) for creating the terahertz radiation, and a receiver with a receiver antenna (3) that can be activated by the same laser light source (1), wherein the transmission antenna (2) comprises a photo diode as a light-sensitive element and the receiver antenna (3) a fast photo-conductor as a light-sensitive element. The invention further relates to a use of such a device for analyzing a sample.