Terahertz radiation transmitting and receiving device and its control device

Abstract

To provide a terahertz (THz) apparatus for transmitting and / or receiving THz radiation.SOLUTION: A terahertz (THz) apparatus for transmitting and / or receiving THz radiation is provided, comprising at least one THz element designed to transmit and / or receive THz radiation, and a digital data processing device designed to at least temporarily process a first signal of at least one component of the apparatus.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to devices for transmitting and / or receiving terahertz, THz, radiation, hereinafter also referred to as "THz devices."

[0002] The present invention also relates to a control device for at least temporarily controlling the operation of at least one THz device. Summary of the Invention

[0003] A preferred embodiment relates to an apparatus for transmitting and / or receiving terahertz (THz) radiation, comprising at least one THz element designed to transmit and / or receive THz radiation, and a digital data processing device, in particular the digital data processing device designed to at least temporarily process at least one first signal in at least one component of the apparatus, so that the at least one first signal can already be processed in the THz device.

[0004] In a further preferred embodiment, the at least one THz element is designed to detect at least one THz signal and to output an output signal, in particular an electrical output signal, characterizing the detected THz signal, and the THz apparatus comprises a digitization stage designed to convert the output signal of the at least one THz element into a first digital signal, which, by way of example, can be processed by a digital data processing device.

[0005] In a further preferred embodiment, the digitization stage comprises an analog-to-digital converter and optionally at least one amplifier, in particular a transimpedance amplifier.

[0006] In a further preferred embodiment, the digital data processing device comprises at least one of the following elements: a) a microprocessor; b) a microcontroller; c) a programmable logic module, in particular an FPGA; d) a digital signal processor, DSP; e) a graphics processor, GPU; f) ​​an application specific integrated circuit, ASIC.

[0007] In a further preferred embodiment, the THz radiation has a frequency range of 0.1 THz to 10 THz, in particular 3 THz to 10 THz, more in particular 4.5 THz to 6.5 THz.

[0008] In a further preferred embodiment, the device has a housing, and in particular at least one component of the device, more particularly several components, particularly preferably all components of the device, are arranged in and / or on the housing. This makes it possible to provide a measurement head that can be flexibly used for THz radiation. In a further preferred embodiment, at least one THz element is assigned a THz optics system, which can also preferably be integrated into any housing.

[0009] In a further preferred embodiment, the digital data processing device is designed to at least temporarily control the operation of the THz device or at least one component of the THz device.

[0010] In a further preferred embodiment, the digital data processing device and / or the THz device can be at least temporarily controlled by at least one external unit.

[0011] In a further preferred embodiment, a digital data processing device and / or a THz device is at least temporarily capable of operating autonomously and therefore, in particular, is capable of operating without needing (eg constant) control by, for example, an external unit.

[0012] In a further preferred embodiment the THz device and / or the digital data processing device comprises at least one memory device for at least temporarily storing computer programs and / or data, in particular the data comprising at least one of the following elements: a) calibration data, in particular calibration data for at least one component of the THz device, b) model data characterizing at least one component of the device or model data characterizing at least one model for a component of the THz device, c) data of reference measurements, d) data characterizing at least a part of the THz signal to be received and / or transmitted.

[0013] In a further preferred embodiment, a reference measurement is performed, e.g. a measurement at one or more spatial locations of the THz device relative to a reference unit (e.g. a reference measurement using a (known) reference measurement object), preferably at the source / focus of the THz radiation.

[0014] In a further preferred embodiment, the digital data processing device is designed to at least temporarily perform at least one of the following processes: a) background correction, b) pulse pile-up correction, c) filtering, in particular pre-filtering, d) averaging, e) correction of the THz data with reference measurements, f) providing time domain signals and / or frequency domain signals, g) characterizing at least a portion of the data, in particular the received and / or transmitted THz signals.

[0015] In a further preferred embodiment, the background correction comprises at least one of the following elements: a) performing at least one measurement by the THz device without a measured object, b) determining a measurement signal, for example in the time domain, c) storing the measurement signal at least temporarily, in particular in a digital data processing device and / or a memory accessible to the digital data processing device, d) performing a further measurement, for example a reference measurement using a (known) reference measured object and / or a sample measurement using the measured object, e) processing the further measurement based on the measurement signal, in particular subtracting the measurement signal from the further measurement.

[0016] In a further preferred embodiment the THz device has at least one first, in particular digital, interface, in particular for preferably bidirectional data exchange with at least one external unit, in particular the first interface being wired or wireless.

[0017] It is provided in a further preferred embodiment that the THz device and / or at least one component of the THz device is designed to transmit and / or receive via the first interface at least one of the following signals: a) a clock signal, in particular a clock signal for synchronization with at least one external unit or at least one external unit, b) a trigger signal, c) a data signal, in particular a data signal characterizing at least a part of the THz signal to be received and / or transmitted, d) aa) the position of the THz device in space and / or bb) the form of the measurement object and / or cc) the distance between the THz device and the measurement object.

[0018] In a further preferred embodiment, the first interface is designed for two-way real-time communication.

[0019] In a further preferred embodiment, the THz device is a THz device or at least It has at least one second interface for the at least temporary, in particular electrical, energy supply of one of the components.

[0020] In a further preferred embodiment, the THz device comprises at least one third, in particular optical, interface for at least temporarily receiving optical radiation, in particular pulsed laser radiation, in particular from at least one external unit.

[0021] In a further preferred embodiment, the THz device is designed to receive, via a third interface, at least two laser signals that are at least temporally distinct.

[0022] In a further preferred embodiment, the THz device comprises at least one device for determining a) the position of the THz device in space, and / or b) the shape of the measurement object, and / or c) the distance between the THz device and the measurement object.

[0023] The THz device is designed to provide a protective gas flow comprising a protective gas in at least one region of the beam path of the THz radiation, in particular the protective gas comprises at least one of the following elements or is formed from at least one of the following elements: a) dry air, b) dry gas, c) dry gas mixture, d) at least one gas that has no absorption lines in the frequency range of the THz radiation, in particular the protective gas has a dew point temperature of -20°C or less, preferably -30°C or less, more preferably -40°C or less, and in particular the protective gas has a dew point temperature of the THz radiation of preferably 0.1 dB or less for each frequency of the THz radiation along the beam path.

[0024] In a further preferred embodiment, the THz device further comprises a) at least one supply device for at least temporarily supplying a protective gas flow, and / or b) at least one pressure-influencing member for influencing the pressure of the protective gas.

[0025] In a further preferred embodiment, the THz device further comprises at least one nozzle, in particular the nozzle is designed and / or arranged to guide the protective gas flow or at least a part of the protective gas flow into at least one region of the beam path of the THz radiation, in particular the at least one nozzle is a free jet nozzle.

[0026] In a further preferred embodiment it is provided that the THz device comprises at least one positioning unit designed to at least temporarily a) move the THz device relative to the measurement object and / or b) relative to the target system in which the THz device is arranged. In a further preferred embodiment the at least one positioning unit can for example comprise at least one robot.

[0027] In a further preferred embodiment, the THz device is designed to perform closed-loop positioning (i.e., in particular, controlled positioning in the sense of a closed control loop), in particular to perform and / or enable closed-loop positioning based on data of the device for determining aa) the position of the THz device in space, and / or bb) the morphology of the measurement object, and / or cc) the distance between the THz device and the measurement object.

[0028] In a further preferred embodiment, the device data for determining aa) the position of the THz device in space and / or bb) the shape of the measurement object and / or cc) the distance between the THz device and the measurement object can for example be used on the basis of reference data, e.g. with a certain tolerance, to provide the relative position of the measurement object within the area where the source or focus of the THz radiation is present.

[0029] Further preferred embodiments are for transmitting and / or receiving terahertz (THz) radiation. The present invention relates to a control device for at least temporarily controlling the operation of at least one THz device for, in particular, at least one THz device designed according to a preferred embodiment, the control device having at least one first, in particular digital, interface for, in particular bidirectional, data exchange with at least a THz device, in particular the first interface being wireless.

[0030] In a further preferred embodiment, the first interface of the control device is designed for two-way real-time communication.

[0031] In a further preferred embodiment, the control device is designed to control the operation of multiple THz devices simultaneously and / or in an at least partially time-overlapping manner and / or in a time-multiplexed manner.

[0032] In a further preferred embodiment, the control device is designed to transmit and / or receive via the first interface at least one of the following signals: a) clock signals, b) trigger signals, c) data signals, in particular data signals characterizing at least a part of the THz signals to be received and / or transmitted, d) measurement data of the device determining aa) the position of the THz device in space, and / or bb) the morphology of the measurement object, and / or cc) the distance between the THz device and the measurement object.

[0033] In a further preferred embodiment, the control device comprises at least one second interface, in particular an optical interface, for at least temporarily outputting the first pulsed laser radiation and / or the second pulsed laser radiation to the at least one THz device.

[0034] In a further preferred embodiment, the control device comprises at least one laser device for generating a first pulsed laser radiation having a first pulse frequency and for generating a second pulsed laser radiation having a second pulse frequency, in particular the second pulse frequency being at least temporarily different from the first pulse frequency.

[0035] It is provided in a further preferred embodiment that the at least one laser device comprises at least one, preferably two, pulsed laser sources, in particular femtosecond, fs pulsed laser sources.

[0036] In a further preferred embodiment, the control device is designed to output the first pulsed laser radiation and / or the second pulsed laser radiation to the multiple THz devices at least temporarily, in particular simultaneously or at least partially overlapping in time or time-multiplexed.

[0037] In a further preferred embodiment, the control device comprises at least one optical beam splitter and / or optical switch, in particular adapted to selectively supply the first pulsed laser radiation and / or the second pulsed laser radiation to one or more THz devices.

[0038] In a further preferred embodiment it is provided that the optical beam splitter and / or the optical switch is wavelength neutral.

[0039] In a further preferred embodiment, the optical beam splitter and / or optical switch has a maximum attenuation of 1.0 dB, in particular 0.2 dB in the wavelength range between 1450 nm and 1650 nm, in particular 1500 nm and 1600 nm.

[0040] The optical beam splitter and / or optical switch is adapted to ensure that at least 80%, in particular 90%, of the total power of the (first and / or second pulse) laser radiation is at the central wavelength ( Specifically designed to transmit over a wavelength range of + / - 100 nm around the center wavelength (between + / - 50 nm).

[0041] In a further preferred embodiment, a plurality of optical fibre devices are provided for supplying the first pulsed laser radiation and / or the second pulsed laser radiation to a plurality of THz devices.

[0042] In a further preferred embodiment, some, preferably each, of the plurality of light guide devices are dispersion-matched and / or length-matched to a maximum optical path length difference of + / - 6 cm, in particular + / - 3 cm, which allows particularly efficient operation for THz signals.

[0043] It is provided in a further preferred embodiment that the at least one laser device comprises at least one, preferably two, continuous wave (CW) or quasi-continuous wave (QCW) laser sources.

[0044] In a further preferred embodiment, the control device comprises at least one third interface for the at least temporary electrical energy supply of at least one component of the at least one THz device.

[0045] In a further preferred embodiment, the control device has at least one fourth interface, in particular for bidirectional data exchange, with at least one external component, for example a control computer.

[0046] In a further preferred embodiment it is provided that the control device has at least one digital signal processing device (e.g., DSP), in particular the at least one digital signal processing device is designed to process at least one signal received by the at least one THz device.

[0047] Further preferred embodiments relate to a system comprising at least one THz device according to an embodiment and comprising at least one control device according to an embodiment.

[0048] Further preferred embodiments relate to a method for operating a terahertz, THz, and an apparatus for transmitting and / or receiving terahertz, THz, comprising at least one THz element designed to transmit and / or receive THz radiation, and a digital data processing device for at least temporarily processing at least one first signal of at least one component of the THz apparatus.

[0049] A further preferred embodiment relates to a method for operating a control device for at least temporarily controlling the operation of at least one THz device for transmitting and / or receiving terahertz, THz, radiation, in particular the at least one THz device is designed according to the embodiment, the control device having at least one first, in particular digital, interface for, in particular bidirectional, data exchange with the at least THz device, in particular the first interface being wired or wireless, and the control device at least temporarily exchanging data with the at least one THz device, preferably with multiple THz devices, in particular for controlling the at least one THz device or multiple THz devices.

[0050] Further preferred embodiments relate to the use of the THz device according to the embodiments and / or the control device according to the embodiments and / or the system according to the embodiments and / or the method according to the embodiments for at least one of the following aspects: a) performing multiple THz measurements simultaneously and / or offset in time and / or alternating in time, in particular with respect to at least one measurement object; b) signal processing or pre-processing of signals related to at least one THz signal, in particular by at least one THz device and / or by at least one control device; c) centrally controlling multiple THz devices; d) positioning a plurality of THz devices under the control of said at least one control device, in particular by means of at least one positioning unit; e) performing closed-loop positioning based on data from the device that determines, in particular, aa) the position of the THz device in space, and / or bb) the shape of the measurement object, and / or cc) the distance between the THz device and the measurement object.

[0051] Further features, possible applications and advantages of the preferred embodiments will become apparent from the following description of exemplary embodiments shown in the drawing figures, in which context all the features described or shown, individually or in any desired combination, constitute the subject matter of the invention, regardless of the claims or the abstract on the back thereof, and regardless of their wording or presentation in the specification or drawings. [Brief explanation of the drawings]

[0052] [Figure 1] FIG. 1 shows a schematic block diagram of a THz device according to a preferred embodiment. [Figure 2] FIG. 2 shows a schematic block diagram of an embodiment of a THz device according to a further preferred embodiment. [Figure 3] FIG. 3 shows a schematic block diagram of an embodiment of a THz device according to a further preferred embodiment. [Figure 4] FIG. 4 shows a schematic block diagram of a data processing unit of a THz device according to a further preferred embodiment. [Figure 5] FIG. 5 shows a schematic block diagram of a THz device according to a further preferred embodiment. [Figure 6] FIG. 6 shows a schematic block diagram of a THz device according to a further preferred embodiment. [Figure 7] FIG. 7 shows a schematic block diagram of a THz device according to a further preferred embodiment. [Figure 8] FIG. 8 shows a schematic block diagram of a THz device according to a further preferred embodiment. [Figure 9] FIG. 9 shows a schematic block diagram of a control device according to a further preferred embodiment. [Figure 10]FIG. 10 shows a schematic block diagram of a control device according to a further preferred embodiment. [Figure 11] FIG. 11 shows a schematic block diagram of a system according to a further preferred embodiment. [Figure 12] FIG. 12 shows a schematic block diagram of a system according to a further preferred embodiment. [Figure 13A] FIG. 13A shows a schematic representation of a portion of a supply line according to a further preferred embodiment. [Figure 13B] FIG. 13B shows a schematic representation of a portion of a fiber optic device according to a further preferred embodiment. [Figure 14] FIG. 14 shows a simplified block diagram according to a further preferred embodiment. [Figure 15] FIG. 15 shows a simplified block diagram of a system according to a further preferred embodiment. [Figure 16] FIG. 16 shows a simplified block diagram of a system according to a further preferred embodiment. [Figure 17] FIG. 17 shows a simplified flowchart of a method according to a further preferred embodiment. [Figure 18] FIG. 18 shows a simplified flowchart of a method according to a further preferred embodiment. [Figure 19] FIG. 19 shows a simplified flowchart of a method according to a further preferred embodiment. [Figure 20] FIG. 20 shows a simplified flowchart of a method according to a further preferred embodiment. [Figure 21] FIG. 21 shows a schematic illustration of a mode of use according to a further preferred embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0053] 1 shows a schematic block diagram of a THz device 100 according to a preferred embodiment. The THz device 100 is designed to transmit and / or receive THz radiation TS1, TS2 and to this end comprises at least one THz element 110 designed to generate or transmit THz radiation TS1 and / or to receive or detect THz radiation TS2.

[0054] In a further preferred embodiment, the THz radiation TS1, TS2 has a frequency range of 0.1 THz to 10 THz, in particular 3 THz to 10 THz, and more in particular 4.5 THz to 6.5 THz.

[0055] In a further preferred embodiment, by way of example, the THz device 100 is able to generate THz radiation TS1, in particular in the form of pulsed THz radiation TS1, and emit it onto the measurement object (see FIG. 6 below). In a further preferred embodiment, the THz device 100 is able to receive or detect THz radiation TS2, which may be reflected by the measurement object OBJ. This allows for measurements of the time domain reflectometry type.

[0056] In a further preferred embodiment, the THz device 100 has an optional housing 102, in particular in which at least one component 110, 120 of the device 100, more particularly in which several components, particularly preferably all components of the device, are arranged in and / or on the housing 102. This makes it possible to provide a measurement head 102 that can be flexibly used for THz radiation. In a further preferred embodiment, an optional THz optics 111 can preferably likewise be integrated into the optional housing 102 and is assigned to at least one THz element 110.

[0057] In some preferred embodiments, the THz element 110 can be designed as a THz transmitter. In further preferred embodiments, the THz element 110 can be designed as a THz receiver or detector. In further preferred embodiments, the THz element 110 can be designed as a THz transceiver.

[0058] The THz apparatus 100 further preferably comprises a digital data processing device 120, which is especially designed to at least temporarily process at least one first signal S1 of at least one component 110 of the THz apparatus 100. Thereby, signal processing of the at least one first signal S1 can e.g. already be performed in the THz apparatus 100 before optionally forwarding the signal S1 to the external unit 200.

[0059] A further preferred embodiment is provided, and with reference to FIG. 2, a THz element 110a (e.g., designed to be comparable to the THz element 110 shown in FIG. 1) detects at least one THz signal TS2 and outputs an output signal AS, in particular an electrical signal (in particular an analog signal, e.g., continuously or time-continuously), characterizing the detected THz signal TS2. The THz apparatus 100 (FIG. 1) comprises a digitization stage 130 (FIG. 2) designed to convert the output signal AS of the at least one THz element 110a into a first digital signal DS1 (value-discrete and time-discrete). By way of example, this first digital signal DS1 can be processed by a digital data processing device 120, resulting in, for example, a second digital signal DS2.

[0060] In a further preferred embodiment, functionality comparable to digitization stage 130 may also be integrated into digital data processing device 120 (not shown).

[0061] A further preferred embodiment is provided, referring to Figure 3, which shows that the digitization stage 130 comprises an analog-to-digital converter 132 and, optionally, at least one amplifier 134, in particular a transimpedance amplifier (TIA). In a further preferred embodiment, the TIA 134 amplifies the output signal as, resulting in an amplified signal as', which is for example converted by the analog-to-digital converter 132 into a first digital signal DS1.

[0062] In a further preferred embodiment it is provided that the THz device 100 (FIG. 1) has at least one first, in particular digital, interface 140, in particular for data exchange DA, preferably bidirectional, in particular real-time capable, with at least one optional external unit 200, wherein in particular the first interface 140 is wired (e.g. Ethernet, preferably Fieldbus or other real-time communication system, e.g. EtherCAT, Profibus) or wireless (e.g. WLAN, (cellular) mobile radio system, in particular according to the 4G or 5G or 6G standard). As a result, in a further preferred embodiment an analog interface or signal connection to the external unit 200 can be dispensed with, at least as far as data transmission of data characterizing the THz signal is concerned.

[0063] In a further preferred embodiment, the first data interface 140 is specifically designed to transfer digital data or signals DS1, DS2 (FIG. 2) using digital modulation and / or encoding processes.

[0064] It is provided in a further preferred embodiment that the digital data processing device 120 (FIG. 1) comprises at least one of the following elements: a) a microprocessor; b) a microcontroller; c) a programmable logic module, in particular an FPGA; d) a digital signal processor, DSP; e) a graphics processor, GPU; f) ​​an application specific integrated circuit, ASIC.

[0065] 4 shows by way of example a simplified block diagram of one possible configuration 1200 for the digital data processing device 120 according to a further preferred embodiment. The digital data processing device 1200 according to Fig. 4 comprises, for example, a computer device 1202 and a memory device 1204 allocated to the computer device 1202 for at least temporarily storing data DAT and / or a computer program PRG for controlling the operation of the THz apparatus 100 or at least one component thereof. In a further preferred embodiment, at least one computer program PRG may also be provided by the data processing device 120, 1200 for controlling, in particular, digital processing of data or signals of the THz apparatus 100.

[0066] The memory device 1204 preferably includes volatile memory, such as random access memory (RAM) 1204a, and non-volatile memory 1204b (eg, flash EEPROM).

[0067] In a further preferred embodiment, the data processing device 120 comprises a data interface 1206 for data exchange with, for example, the digitization stage 130, via which, for example, the digital signal DS1 (FIG. 2) can be supplied to the data processing device 120.

[0068] In a further preferred embodiment, the first interface 140 may also be implemented by the data interface 1206 (see double arrow 140a in FIG. 4).

[0069] In a further preferred embodiment, the digital data processing device 120, 1200 is designed to at least temporarily control the operation of the THz device 100 (FIG. 1) or at least one component of the THz device.

[0070] In a further preferred embodiment, the digital data processing device 120, 1200 and / or the THz apparatus 100 can be at least temporarily controlled by at least one external unit 200 (Fig. 1). By way of example, for this purpose the THz apparatus 100 or its data processing device 120, 1200 can at least temporarily receive control commands from the external unit 200 via the first interface 140.

[0071] The digital data processing device 120, 1200 and / or the THz apparatus 100 may operate autonomously at least temporarily, and thus may in particular operate autonomously without requiring control (e.g., constant or at least temporary) by, for example, an external unit 200.

[0072] In a further preferred embodiment it is provided that the THz apparatus 100 and / or the digital data processing device 120, 1200 have at least one memory device 1204 (Figure 4) for at least temporarily storing the computer program PRG and / or the data DAT, in particular the data DAT having at least one of the following elements: a) calibration data, in particular calibration data for at least one component 110 of the THz apparatus 100, b) model data characterizing at least one component of the apparatus 100 or at least one model for a component of the THz apparatus 100.

[0073] In a further preferred embodiment, characteristic calibration data (e.g., for the position and / or distance sensitivity of any THz optics 111 assigned to the THz element 110) and / or reference data (e.g., characterizing the instrument profile and / or reference pulse at optimal alignment or at one or more defined spatial positions of the THz device 100) can be stored relative to a reference unit in the memory device 1204 of the THz device 100 or its data processing device 120, 1200 and can be used there, e.g., for corresponding calibration or signal processing.

[0074] In a further preferred embodiment, a transfer function may be calculated, for example, in a frequency range and transferred by the data processing device 120, 1200 to the external unit 200, in particular instead of / in addition to transferring digital signals DS1, DS2, which digital signals DS1, DS2, for example, characterize the time profile of the THz radiation ZS2 detected by the THz element 110 or a signal derived therefrom.

[0075] In a further preferred embodiment a digital data processing device 120, 1200 is provided which is designed to at least temporarily perform at least one of the following processes: a) background correction, b) pulse pile-up correction, c) filtering, in particular pre-filtering, d) averaging, e) correction of the THz data with reference measurements, f) providing time domain and / or frequency domain signals, g) data, in particular receiving and and / or characterizing at least a portion of the THz signal to be transmitted.

[0076] In a further preferred embodiment it is provided that the THz device 100 and / or at least one component of the THz device 100 is designed to transmit and / or receive at least one of the following signals via the first interface 140: a) clock signals, in particular clock signals for synchronization with at least one external unit 200 or at least one external unit 200, b) trigger signals (for example for triggering an operation such as generating THz radiation TS1 or detecting THz radiation TS2), c) data signals, in particular data signals characterizing at least a part of the THz signal to be received and / or transmitted.

[0077] A further preferred embodiment is provided, in which, with reference to FIG. 5 , the THz device 100a has at least one second interface 150 for at least a temporary, in particular electrical, energy supply EV of the THz device 100a or of at least one component of the THz device 100a.

[0078] In a further preferred embodiment, an electrical operating voltage U can be supplied to at least one component 120 of the THz device 100 a, for example via a second interface 150 .

[0079] In a further preferred embodiment, for example, a bias voltage can be supplied to at least one element 110 via the second interface 150 .

[0080] In further preferred embodiments, the bias voltage of the at least one THz element 110 may also be generated locally in the THz device 100, 100a, e.g., from an electrical operating voltage U provided via the second interface 150. It is also envisaged in further preferred embodiments that a variable (and therefore dynamic, i.e., with respect to the runtime of the THz device 100, 100a) bias voltage is provided (e.g., directly via the second interface 150 or locally within the THz device 100, 100a, e.g., derived from the operating voltage U).

[0081] In a further preferred embodiment, the THz device 100a (FIG. 5) has at least one third, in particular optical, interface 160, adapted to at least temporarily receive optical radiation OS, in particular pulsed laser radiation, in particular from at least one external unit, for example from external unit 200.

[0082] In a further preferred embodiment, it is envisaged that the THz device 100a is designed to receive via the third interface 160, for example from an external unit 200, at least two laser signals that are at least temporally distinct.

[0083] A further preferred embodiment is provided, in which, with reference to FIG. 6, the THz apparatus 100b has at least one device 170 for determining a) the position of the THz apparatus 100b in space, and / or b) the shape of the measurement object OBJ, and / or c) the distance between the THz apparatus 100b and the measurement object OBJ.

[0084] In a further preferred embodiment, the device 170 is designed to trigger the recording of the output signal AS (FIG. 2) or the conversion of the output signal AS into a digital signal DS1, in particular based on a predetermined position and / or angular orientation of the THz device 100b or the measurement head 102 relative to the measurement object OBJ. This allows the detection of the incoming THz radiation TS2 to be synchronized with, for example, a predetermined orientation of the measurement head 102, e.g., the device 170 is preferably This allows for particularly accurate THz measurements, as the analog-to-digital converter 132 (FIG. 3) can be designed to trigger it.

[0085] In a further preferred embodiment, an external trigger may alternatively or additionally be provided (a trigger signal, for example, transmitted by the outside 200 via the first interface 140) to trigger the device 170 and / or the analog-to-digital converter 132.

[0086] Furthermore, in a preferred embodiment, the data recording or pick-up based on the received THz signal TS2 and the position determination of the measurement head 102 are synchronized by the device 170.

[0087] A further preferred embodiment is provided, with reference to FIG. 7, in which a THz device 100c is designed to provide a protective gas flow SGS with a protective gas SG in at least one region of the beam path BP of the THz radiation TS1, TS2, in particular the protective gas SG comprises or is formed from at least one of the following elements: a) dry air, b) dry gas, c) dry gas mixture, d) at least one gas that has no absorption lines in the frequency range of the THz radiation, in particular a protective gas having a dew point temperature of -20°C or less, preferably -30°C or less, more preferably -40°C or less, in particular a protective gas SG that preferably causes an attenuation of the THz radiation TS1, TS2 along the beam path of less than 0.1 dB for each frequency of the THz radiation TS1, TS2.

[0088] In a further preferred embodiment it is provided that the THz device 100c further comprises a) at least one supply device 180 for at least temporarily supplying a protective gas flow SGS, and / or b) at least one pressure influencing member (not shown) for influencing the pressure of the protective gas SG.

[0089] In a further preferred embodiment, the THz device 100c further comprises at least one nozzle 182, in particular the nozzle 182 is designed and / or arranged to guide the protective gas flow SGS or at least a part of the protective gas flow SGS into at least one region of the beam path BP of the THz radiation TS1, TS2, in particular the at least one nozzle 182 is a free jet nozzle.

[0090] A further preferred embodiment 100d is provided, in which reference is made to Fig. 8, which shows that the THz device 100d comprises at least one positioning unit 190 designed to at least temporarily move the THz device 100d a) relative to the measurement object OBJ and / or b) relative to the target system ZS (e.g. part of an (industrial) manufacturing facility) in which the THz device 100d is arranged. In a further preferred embodiment, the at least one positioning unit 190 may for example comprise at least one robot.

[0091] In a further preferred embodiment, the robot 190 is also capable of carrying or carrying or positioning a plurality of devices 100, 100a, 100b, 100c, 100d according to the embodiment.

[0092] In a further preferred embodiment, the THz device is designed to perform and / or enable closed-loop positioning (i.e., in particular, controlled positioning in the sense of a closed control loop), in particular based on data from the device 170 for determining aa) the position of the THz device in space and / or bb) the shape of the measurement object and / or cc) the distance between the THz device and the measurement object OBJ.

[0093] In a further preferred embodiment, the data of the device 170 is for example based on which the relative position of the measurement object OBJ is calculated, for example with a certain tolerance, from reference data, for example THz radiation. The resulting reference data can be used to improve future measurements.

[0094] A further preferred embodiment, with reference to Figure 9, relates to a control device 200 for at least temporarily controlling the operation of at least one THz device for transmitting and / or receiving terahertz, THz, radiation, in particular at least one THz device 100, 100a, 100b, 100c, 100d designed according to the preferred embodiment, the control device 200 having at least one first, in particular digital, interface 210 for, in particular bidirectional, in particular real-time capable data exchange with at least a or the THz device 100, 100a, 100b, 100c, 100d.

[0095] In a preferred embodiment, the first interface 210 of the controlled de-icing 200 may, for example, be of the same or identical type as the first interface 140 of the THz device 100 .

[0096] The control device 200 (Fig. 9) is designed to control the operation of multiple, simultaneous and / or at least partially overlapping in time and / or time multiplexed THz devices, which for clarity are collectively designated by the reference numeral 100' in Fig. 9. In a further preferred embodiment, at least one of the multiple THz devices 100' according to Fig. 9 may have the configuration 100, 100a, 100b, ... as described above by way of example with reference to Figs. 1 to 8.

[0097] In a further preferred embodiment, the control device 200 is designed in particular to transmit to the at least one THz device 100′ and / or to receive via the first interface 210 at least one of the following signals: a) a clock signal CLK, b) a trigger signal TRIG, c) a data signal DS, in particular characterizing at least a part of the THz signal to be transmitted, d) aa) the position of the THz device in space and / or bb) the form of the object to be measured OBJ and / or cc) the distance between the THz device and the object to be measured OBJ.

[0098] In a further preferred embodiment, the control device 200 is designed to at least temporarily send control commands to the at least one THz device 100′, e.g. for controlling the operation of the at least one THz device 100′. As an example, the at least one THz device 100′ or its respective data processing device 120, 1200 may at least temporarily receive control commands from the external unit 200 via the first interface 140 and perform its operation based thereon.

[0099] A further preferred embodiment is provided, in which, with reference to FIG. 10, it is shown that the control device 200a has at least one second interface 220, which is an optical interface, in particular for at least temporarily outputting the first pulsed laser radiation PL1 and / or the second pulsed laser radiation PL2 to the at least one THz device 100_1, 100_2, 100_3.

[0100] In a further preferred embodiment, the control device 200a comprises at least one laser device 230 for generating a first pulsed laser radiation PL1 having a first pulse frequency and for generating a second pulsed laser radiation PL2 having a second pulse frequency, in particular the second pulse frequency being at least temporarily different from the first pulse frequency.

[0101] In a further preferred embodiment, it is provided that the at least one laser device 230 comprises at least one, preferably two, pulsed laser sources 230a, 230b, in particular femtosecond fs, pulsed laser sources 230a, 230b.

[0102] In a further preferred embodiment, the control device 200a is designed to output the first pulsed laser radiation PL1 and / or the second pulsed laser radiation PL2 to the multiple THz devices 100_1, 100_2, 100_3 at least temporarily, in particular simultaneously or at least partially overlapping in time or time multiplexed, so that the operation of the multiple THz devices 100_1, 100_2, 100_3, in particular the operation of their respective THz elements 110, e.g., the detection of incoming THz radiation TS2 and / or the transmission of THz radiation TS1 to be generated, can be efficiently controlled, in particular even synchronized with each other.

[0103] In a further preferred embodiment, the control device 200a comprises at least one optical beam splitter 220′ and / or an optical switch, in particular adapted to selectively supply the first pulsed laser radiation PL1 and / or the second pulsed laser radiation PL2 to one or more of the THz devices 100_1, 100_2, 100_3. In a further preferred embodiment, a first THz element (e.g., usable as a THz transmitter) of the THz device may also, for example, at least temporarily supply the first pulsed laser radiation PL1 via the second interface 220 or the beam splitter 220′ to generate a corresponding THz pulse TS1, and a second THz element (e.g., usable as a THz detector) of the same THz device may, for example, at least temporarily supply the second pulsed laser radiation PL2 via the second interface 220 or the beam splitter 220′ to enable or trigger detection of an incoming THz pulse TS2.

[0104] In a further preferred embodiment, it is provided that the optical beam splitter 220' and / or the optical switch are wavelength neutral.

[0105] In a further preferred embodiment, the optical beam splitter 220' and / or the optical switch has a maximum attenuation of 1.0 dB, in particular 0.2 dB, in the wavelength range of 1450 nm (nanometers) to 1650 nm, more particularly in the wavelength range of 1500 nm to 1600 nm.

[0106] The optical beam splitter 220′ and / or the optical switch are designed so that at least 80% of the total power of the (first and / or second pulsed) laser radiation PL1, PL2 is transmitted in a wavelength range of ±100 nm around the center wavelength of the laser radiation PL1, PL2 (in particular, between ±50 nm relative to the center wavelength range).

[0107] In a further preferred embodiment, a plurality of optical fiber devices 240 (symbolized in FIG. 10 for clarity by dashed arrows) are provided to supply first pulsed laser radiation and / or second pulsed laser radiation to a plurality of THz devices 100_1, 100_2, 100_3, respectively.

[0108] In a further preferred embodiment, some, preferably each, of the plurality of optical fiber devices 240 are dispersion-matched and / or length-matched to a maximum optical path length difference of + / - 6 cm, in particular + / - 3 cm. This allows particularly efficient operation for THz signals. A further preferred embodiment is provided in which the at least one laser device 230 comprises at least one, preferably two, continuous wave (CW) or quasi-continuous wave (QCW) laser sources, so that, for example, processes based on the principles of frequency domain spectroscopy can be performed.

[0109] In a further preferred embodiment, the control device 200a is adapted to control the at least temporary electrical energy supply EV (see also FIG. 5) of at least one component of at least one THz device. The device has at least one third interface 250 for transmitting the data.

[0110] In a further preferred embodiment it is provided that the control device 200a has at least one fourth interface 260, in particular for bidirectional data exchange, with at least one (in particular further) external component 10, e.g. a control computer.

[0111] In a further preferred embodiment it is provided that the control device 200a has at least one digital signal processing device (e.g., DSP) 270, in particular the at least one digital signal processing device 270 is designed to process at least one signal received by at least one THz device 100_1, 100_2, 100_3.

[0112] In a further preferred embodiment, the signal processing device 270 may have essentially similar or identical structure and / or functionality to the configuration 1200 of FIG. 4, for example.

[0113] 11, a further preferred embodiment relates to a system 1000 having at least one THz device 100e according to an embodiment and having at least one control device 200b according to an embodiment. The THz device 100e has a first THz element 110_1 designed to transmit THz radiation TS1 and a second THz element 110_2 designed to receive THz radiation TS2. As an example, the second THz element 110_2 can receive THz radiation TS2 from the first THz element 110_1, in particular, transmitted on a measurement object and reflected by the measurement object.

[0114] The control device 200b has a first pulsed laser source 230a that generates a first laser signal s10a and a second pulsed laser source 230b that generates a second laser signal s10b. The first laser signal s10a can be used, for example, in the first THz element 110_1 to generate THz radiation TS1 to be transmitted by known impingement, for example, on a switch made of a photoconductive material, and the second laser signal s10b can be used, for example, in the second THz element 110_2 to detect received THz radiation TS2 by known impingement, for example, on a THz detector made of a photoconductive material.

[0115] Portions of the laser signals s10a, s10b are coupled out by beam splitters 231a, 231b and supplied to optoelectronic detectors 232a, 232b (e.g., photodiodes), which output corresponding electrical signals s11a, s11b to a phase detector 233. A combiner 235 (particularly an adder) combines the output signal of the phase detector 233, characterizing the phase difference between the laser signals s10a, s10b, with the output signal of the function generator 234. The output signal of the combiner 235 is supplied to a controller, particularly a PID controller 236, which generates a control signal s12 based on the output signal of the combiner 235 and outputs it to the second pulsed laser source 230b, so that, for example, the oscillator length of the second pulsed laser source 230b can be affected by, for example, a piezoelectric actuator (not shown) controlled by the control signal s12. If necessary, an optional amplifier (also not shown) can be provided to provide the control signal s12 in the voltage range required for the piezoelectric actuator (e.g., tens of volts or more).

[0116] As a result, the phase of the second laser signal s10b can be specified and specifically adjusted relative to the first laser signal s10a, which can be achieved, for example, by specifying a corresponding output signal (e.g., a sawtooth or triangular wave) of the function generator 234.

[0117] The THz radiation TS2 detected by the second THz element 110_2, or an electrical signal characterizing the detected THz radiation TS2, is converted into a digital signal by a digitization stage 130′, for example. Further processing can be performed and the digitization stage 130' can for example have the same design as the digitization stage 130 according to FIG.

[0118] The digital output signal DA of the digitization stage 130' can be supplied in a further preferred embodiment of a digital signal processor 270', eg to a controller 200b for further processing.

[0119] The control device 200b may optionally comprise an electrical supply 237 designed to at least temporarily supply a bias voltage U_B to at least the first THz element 100_1.

[0120] In a further preferred embodiment, the interface between the control device 200b and the THz device 100e can have at least one of the following elements: b) at least one light guide device (not shown in FIG. 11) for transferring the first and / or second laser signals s10a, s10b to the THz device 100e, b) at least one digital data interface for digital exchange of data DA between the THz device 100e and the control device 200b, c) at least one interface for electrical energy supply (e.g. bias voltage), where in a further preferred embodiment multiple interfaces can be combined with each other, e.g. interfaces according to aspects b) and c). An Ethernet interface compatible with (over Ethernet) may also be used to combine at least one digital data interface with at least one interface for electrical energy supply.

[0121] Figure 12 shows a schematic block diagram of a system 1000a according to a further preferred embodiment. A control device 200c, designed in a similar or identical way to the control device 200 as shown in Figure 10, comprises, for example, three THz devices, designated 100_1, 100_2, 100_3, which are connected to the control device 200c, preferably optically and electrically, via supply lines 280_1, 280_2, 280_3, respectively.

[0122] Figure 13A shows a schematic representation of a portion of a supply line 280 according to a further preferred embodiment. By way of example, in a further preferred embodiment at least one of the supply lines 280_1, 280_2, 280_3 may have a configuration according to Figure 13A.

[0123] The supply line 280 comprises, for example, at least one light-guiding device 240 for supplying laser radiation or a laser signal to the THz device 100, in particular by means of the first pulsed laser radiation PL1 and / or the second pulsed laser radiation PL2.

[0124] For example, at least one light-guiding device 240 (see also FIG. 13B) may have a first optical fiber 241 (see also, e.g., signal S10a in FIG. 11) for supplying first pulsed laser radiation PL1 to the THz device 100, and a second optical fiber 242 (see also, e.g., signal S10b in FIG. 11) for supplying second pulsed laser radiation PL2 to the THz device 100.

[0125] 13A further comprises at least one data line 281 for transferring data between the preferably digital interface 210 of the control device 200 and the preferably digital interface 140 of the THz device 100. In a further preferred embodiment, the data line 281 can also be used by the control device 200 to transfer data to a source of electrical energy supply, for example the THz device 100 (also vice versa).

[0126] In a further preferred embodiment, the supply line 280 according to FIG. 13A may also comprise an optional further electrical conductor device 282, which is designed for example for the electrical energy supply of at least one component of the THz device 100 by the control device 200.

[0127] In some preferred embodiments, a safe extra-low voltage (e.g., 12 volts or 24 volts, etc.) can be provided, for example, by the controller 200, by the optional conductor device 282, for operation of at least some of the components 120, 130, 140 of the THz apparatus 100. In further preferred embodiments, the THz apparatus 100 can be designed to locally generate a bias voltage U_B for at least one THz element 110_1, 110_2 based on the safe extra-low voltage provided by the conductor device 282.

[0128] In further preferred embodiments, the conductor device 282 may also be designed to supply a plurality of different voltages to the THz device 100, for example using a safety extra-low voltage (e.g., 12 volts or 24 volts, etc.) for operation of at least some of the components 120, 130, 140 of the THz device 100, and using a bias voltage U_B for at least one THz element 110_1, 110_2. In these embodiments, both the safety extra-low voltage and the bias voltage may be generated or provided, for example, by the control device 200, respectively, and supplied to at least one THz device 100; 100_1, 100_2, 100_3 via the supply line 280 or its conductor device 282.

[0129] Fig. 14 shows a schematic block diagram according to a further preferred embodiment. The optical interface 220 (Fig. 10) of the control device 200 is shown by way of example. In particular, Fig. 14 shows two pulsed laser sources 230a, 230b (see also Figs. 10 and 11). It also shows optical splitters 222a, 222b that split the pulsed laser radiation PL1 or PL2 supplied by the two pulsed laser sources 230a, 230b, respectively, via a number of optical fibers 241a, 241b, ..., 242a, 242b, .... By way of example, the splitters 222a, 222b are designed as optical fiber couplers, beam splitters, or switches.

[0130] For example, the distributor 222a distributes the pulsed laser radiation PL1 provided by the pulsed laser source 230a to the optical fibers 241a, 241b and possibly further optical fibers (symbolized in FIG. 14 by three dots "···" for clarity), for example to forward (parts of) the pulsed laser radiation PL1 to the different THz devices 100_1, 100_2, ···. The same applies to the distributor 222b.

[0131] In a further preferred embodiment, the distributors 222a, 222b are integrated into the control device 200. In a further preferred embodiment, the distributors 222a, 222b may be located externally to the control device 200.

[0132] In a further preferred embodiment, fibers 241a, 242a are assigned to a first feed line 280_1, fibers 241b, 242b are assigned to a second feed line 280_2, etc. Any other electrical or data lines 281, 282 of the respective feed lines 280_1, 280_2 that may be present are likewise not shown in FIG. 14 for the sake of clarity.

[0133] In a further preferred embodiment, the supply lines 280; 280_1, 280_2, 280_3 are at least 1 meter (m), in particular at least 15 m long, preferably at least 20 m. As a result, one or more of the THz devices 100_1, 100_2, 100_3 may advantageously be at least temporarily spatially offset from the control device 200 or may be deployed in a substantially mobile manner and positioned, e.g., relative to at least one measurement object, e.g., by a positioning system such as at least one robot.

[0134] In a further preferred embodiment, the optical fibers 241 a, 242 a, in particular the optical fibers 241 a, 242 a respectively assigned to the same THz device 100_1, are designed so that they have at least approximately the same size attenuation for the laser radiation PL1, PL2, which in a further preferred embodiment is 0.3 dB or less. Particularly preferably, the entire optical path between the THz device 100_1 and the laser sources 230 a, 230 b, and therefore in particular the optical fibers including the splitters 222 a, 222 b, has an attenuation of 0.3 dB or less.

[0135] In a further preferred embodiment, the two optical paths (100_1, 241a, 222a, 230a), (100_1, 242a, 222b, 230b) have a maximum optical path difference between the THz device 100_1 and the corresponding laser source 230a, 230b of +6 centimeters (cm), preferably +3 cm, in particular +1 cm, which allows for particularly accurate THz-based measurements.

[0136] The optical fibers 241a, 241b, . . . , 242a, 242b, . . . are particularly preferably polarization-maintaining (PM) fibers.

[0137] In a further preferred embodiment, using the configuration shown schematically in Fig. 14, a large number of THz devices 100_1, 100_2, ... can be flexibly (and in particular over longer paths, from a few meters to tens of meters or more) supplied by the control device 200 with pulsed laser radiation PL1, PL2 (preferably also accompanied by electrical signals for bidirectional data exchange and / or electrical energy supply), resulting in a correspondingly flexible measurement configuration with a large number of THz devices. This is shown schematically in Fig. 15.

[0138] FIG. 15 illustrates a system 1000b according to a further preferred embodiment. For example, a control device 200 having the configuration of FIG. 10 (or a similar configuration) supplies pulsed laser radiation PL1, PL2 and electrical energy to the first THz device 100_1 via a first supply line 280_1 for operation of the first THz device 100_1. A bidirectional data connection between the control device 200 and the first THz device 100_1 is further realized by the supply line 280_1, which transmits, in particular, time-discrete and value-discrete data characterizing, for example, THz radiation detected by the first THz device 100_1 (or data derived therefrom, e.g., digitally preprocessed (e.g., filtered, etc.) data). Further THz devices 100_2, 100_3 are connected to the control device 200 in a comparable manner, in particular via supply lines 280_2, 280_3.

[0139] A positioning system 190a, 190b is assigned to each of the THz devices 100_1, 100_2, which may be, for example, a robot, for example, an (industrial) robot with three or more degrees of freedom, for example, six degrees of freedom. In this way, the THz devices 100_1, 100_2 can be used to perform flexible, substantially mobile THz measurements on a measurement object OBJ. In contrast, the third THz device 100_3 is designed to be stationary, for example, to be placed on a structure (wall and / or ceiling) not shown in FIG. 15.

[0140] Each of the three THz devices 100_1, 100_2, 100_3 is preferably capable of performing THz-based measurements on an object of measurement OBJ, under the control of the control device 200. For this purpose, for example, the THz devices 100_1, 100_2, 100_3 can irradiate the measurement object OBJ with THz radiation TS12_1, TS12_2, TS12_3 generated locally in each THz device and receive or detect parts of the THz radiation TS12_1, TS12_2, TS12_3 reflected by the measurement object OBJ. The transmission and / or reception or detection can be performed, for example, by applying pulsed laser radiation PL1, PL2 in each case to the corresponding THz element 110 ( FIG. 1 ) of the THz devices 100_1, 100_2, 100_3.

[0141] In a further preferred embodiment, the control device 200 can cause the at least two THz devices 100_1, 100_2 to operate in synchronization with each other, for example by providing a common trigger signal TRIG (FIG. 9) to the two THz devices 100_1, 100_2 via a digital data interface and / or by synchronously applying pulsed laser radiation PL1, PL2 to the THz devices 100_1, 100_2 or their respective THz elements 110, thereby simultaneously triggering or initiating THz-based measurements by the two THz devices 100_1, 100_2.

[0142] In a further preferred embodiment, the controller 200 can operate the at least two THz devices 100_1, 100_2 asynchronously with respect to each other, e.g., can trigger or initiate time-offset or time-independent THz-based measurements on the two THz devices 100_1, 100_2.

[0143]

[0083] Figure 15 shows a system 1000b according to a further preferred embodiment. The control device 200d has, for example, the configuration of Figure 10 (or a similar one), and supplies pulsed laser radiation PL1, PL2 and electrical energy to the first THz device 100_1 via a first supply line 280_1 for operation of the first THz device 100_1. The second THz device 100_2 is connected to the first THz device 100_1 via a second supply line 280_2, which supplies pulsed laser radiation PL1, PL2 and electrical energy for operation of the second THz device 100_2 to the second THz device 100_2 via the second supply line 280_2. The third THz device 100_3 is connected via a third supply line 280_3 to the second THz device 100_2, which supplies pulsed laser radiation PL1, PL2 and electrical energy for the operation of the third THz device 100_3 to the third THz device 100_3 via the third supply line 280_3.

[0144] Thereby, a type of daisy chain connection of multiple THz devices 100_1, 100_2, 100_3 is advantageously realized, which in turn advantageously allows a distributed, approximately mobile use of multiple THz devices 100_1, 100_2, 100_3. In a further preferred embodiment, more than two THz devices shown by way of example may also be connected to each other in this way.

[0145] In a further preferred embodiment, the THz device 100_1 according to Fig. 16 can have an optical interface 160 (Fig. 5) for receiving the pulsed laser radiation PL1, PL2 via a first supply line 280_1, which for example has a beam splitter or coupler (e.g. like the distributor 222a according to Fig. 14) via which part of the pulsed laser radiation PL1, PL2 can be coupled for the operation of the first THz device 100_1 and a further part of the pulsed laser radiation PL1, PL2 can be forwarded via a supply line 280_2 for the operation of the further THz devices 100_2, 100_3. Equivalents can apply in further preferred embodiments for the electrical energy supply and / or preferably bidirectional digital data connection between the further THz devices 100_2, 100_3 or between the control device 200 in each case.

[0146] A further preferred embodiment, referring to Figure 17, relates to a method for transmitting and / or receiving terahertz, THz radiation TS1, TS2, comprising an apparatus 100 (Figure 1) for transmitting and / or receiving terahertz, THz radiation, the apparatus having at least one THz element 110 designed to transmit and / or receive THz radiation TS1, TS2, and a digital data processing device 120, the digital data processing device 120 at least temporarily processing (302) at least one first signal S1 of at least one component 110 of the THz apparatus 100. Optionally, before processing 302, a THz signal TS2 can be received or detected (300). Optionally, after processing 302, the processed data can be transmitted (304) from the THz apparatus 100 to the control device 200 (Figure 9), for example, in particular via a digital data interface. In this case, time-discrete data and value-discrete data, or signals characterized by time-discrete data and value-discrete data, can preferably be transferred.

[0147] In a further preferred embodiment, referring to FIG. 18, the THz device 100 (FIG. 1) receives configuration data from the control device 200 (step 310) and, in step 312, operates the THz device 100 based on the received configuration data.

[0148] A further preferred embodiment, with reference to Figure 19, relates to a method for operating a control device 200 for at least temporarily controlling the operation of at least one THz device 100 for transmitting and / or receiving terahertz, THz, radiation, in particular the at least one THz device is designed according to the embodiment, the control device 200 having at least one first, in particular digital, interface 210 for particularly bidirectional data exchange with at least a or THz device 100, in particular the first interface 210 being wired or wireless, and the control device 200 at least temporarily exchanges 350 data with the at least one THz device, preferably with multiple THz devices 100_1, 100_2, 100_3 (Figures 12, 15, 16), in particular for controlling the at least one THz device or multiple THz devices. In a subsequent step 352, the controller 200 preferably receives digital data from at least one of the plurality of THz devices 100_1, 100_2, 100_3, eg, characterizing at least one detected THz signal.

[0149] A further preferred embodiment is provided, and with reference to Figure 20, wherein the control device 200 operates 360 the at least two THz devices 100_1, 100_2 at least temporarily synchronously, and / or the control device 200 operates 362 the at least two THz devices 100_1, 100_2 at least temporarily asynchronously. In a further preferred embodiment, operation of the multiple THz devices is only possible in a synchronous or asynchronous manner.

[0150] A further preferred embodiment, with reference to FIG. 21, relates to a method 400 according to an embodiment and / or to the use of the control device 200 100_1, 100_2, 100_3 according to an embodiment and / or according to the following aspects: a) performing (402) multiple THz measurements simultaneously and / or alternating in time, in particular with respect to at least one object to be measured; b) performing signal processing or pre-processing of the signals S1, AS, DS1 on at least one THz signal TS2, in particular by at least one THz device 100 and / or by at least one control device 200 (404); c) centrally controlling (406) a plurality of THz devices 100_1, 100_2, 100_3 by means of: d) at least one control device 200, in particular performing a model-based layer thickness measurement (408), in particular at least temporarily using a protective gas, in particular in a production line ("in-line"); positioning (408) the plurality of THz devices 100; 100_1, 100_2, 100_3 at least temporarily in a space ("space") and / or under the control of at least one control device 200, in particular by at least one positioning unit 190; 190a, 190b, in particular performing closed-loop positioning based on data from a device 170 determining aa) the position of the THz device in space and / or bb) the shape of the measurement object OBJ and / or cc) the distance between said THz device and said measurement object OBJ, measuring, in particular on a model basis, the layer thickness of several layers, in particular lacquer layers, which are located on top of one another, at least one of the layers being wet; f2) Measuring, in particular on a model basis, the layer thickness of several layers, in particular lacquer layers, located on top of one another, at least one of the layers being dry.

[0151] (Additional note 1) A terahertz (THz) device (100) for transmitting and / or receiving THz radiation (TS1, TS2), comprising: at least one THz element (110) designed to transmit and / or receive said THz radiation (TS1, TS2); a digital data processing device (120); In particular, said digital data processing device (120) is designed to at least temporarily process at least one first signal (S1, DS1) of at least one component (110) of said THz device (100), Terahertz (THz) device. (Additional note 2) the at least one THz element (110) is designed to detect at least one THz signal (TS2) and to output an electrical output signal (AS) that characterizes the detected THz signal (TS2); The THz device (100) comprises a digitization stage (130) designed to convert the output signal (AS) of the at least one THz element (110) into a first digital signal (DS1), The THz device (100) according to appended item 1. (Additional note 3) 3. The THz device (100) according to claim 2, wherein the digitization stage (130) comprises an analog-to-digital converter (132) and, optionally, at least one amplifier (134), in particular a transimpedance amplifier. (Additional note 4) The digital data processing device (120) includes the following elements: a) a microprocessor; b) a microcontroller; c) programmable logic modules, in particular FPGAs; d) Digital Signal Processor, DSP, e) Graphics processor, GPU, f) A THz device (100) according to at least one of the preceding clauses, comprising at least one of the following: an application specific integrated circuit, ASIC. (Additional note 5) A THz apparatus (100) according to at least one of the preceding clauses, wherein the digital data processing device (120) is designed to at least temporarily control the operation of the THz apparatus (100) or at least one component (110, 130) of the THz apparatus (100). (Additional note 6) The THz apparatus (100) according to at least one of the preceding clauses, wherein the digital data processing device (120) and / or the THz apparatus (100) can be at least temporarily controlled by at least one external unit (200). (Additional note 7) The THz apparatus (100) according to at least one of the preceding clauses, wherein the digital data processing device (120) and / or the THz apparatus (100) are capable of operating at least temporarily autonomously. (Additional note 8) the THz apparatus (100) and / or the digital data processing device (120) have at least one memory device (1204) for at least temporarily storing computer programs (PRG) and / or data (DAT), In particular, said data (DAT) includes the following elements: a) calibration data, in particular calibration data for at least one component of said THz device (100); b) model data characterizing at least one component of the THz device (100) or model data for at least one model of a component of the THz device (100); c) Reference measurement data; d) data characterizing at least a portion of the THz signal to be received and / or transmitted; The THz device (100) according to at least one of the preceding clauses. (Additional note 9) The digital data processing device (120) at least temporarily: a) background correction, b) Pulse pile-up correction; c) filtering, especially pre-filtering; d) averaging; e) Correction of THz data with reference measurements; f) providing a time domain signal and / or a frequency domain signal; g) A THz device (100) according to at least one of the preceding clauses, designed to perform at least one process of data, in particular data characterizing at least a part of the THz signal to be received and / or transmitted. (Additional note 10) the THz device (100) has at least one first, in particular digital, interface (140) for particularly preferably bidirectional data exchange (DA) with at least one external unit (200), In particular, the first interface (140) is wired or wireless; The THz device (100) according to at least one of the preceding clauses. (Additional note 11) The THz device (100) and / or at least one component (110, 130) of the THz device (100) receives via the first interface (140) the following signals: a) a clock signal (CLK), in particular a clock signal (CLK) for at least one external unit (200) or for synchronization with said at least one external unit (200), b) Trigger signal (TRIG), c) a data signal, in particular a data signal characterizing at least a part of the THz signal to be received and / or transmitted; d) measurement data of a device (170) for determining aa) the position of the THz device (100) in space, and / or bb) the shape of a measurement object (OBJ), and / or cc) the distance between the THz device and the measurement object (OBJ); 11. The THz device (100) according to claim 10, which is designed to transmit and / or receive at least one of: (Additional note 12) The THz device (100) according to at least one of supplementary items 10 to 11, wherein the first interface (140) is designed for two-way real-time communication. (Additional note 13) The THz device (100) according to at least one of the preceding claims, wherein the THz device (100) has at least one second interface (150) for an at least temporary, in particular electrical, energy supply (EV) of the THz device (100) or for at least one component (110, 120, 130, ...) of the THz device (100). (Additional note 14) A THz device (100) according to at least one of the preceding claims, wherein the THz device (100) has at least one third, in particular optical, interface (150) for at least temporarily receiving optical radiation (OS), in particular pulsed laser radiation, in particular from at least one external unit (200). (Additional note 15) The THz device (100) according to claim 14, wherein the THz device (100) is designed to receive at least two laser signals that are at least temporarily different via the third interface (OS). (Additional note 16) The THz device (100) a) the position of the THz device (100) in space, and / or b) the shape of the object to be measured (OBJ), and / or c) A THz device (100) according to at least one of the preceding clauses, comprising at least one device (170) for determining a distance between the THz device (100) and the object to be measured (OBJ). (Additional note 17) The THz device (100) is designed to provide a protective gas flow (SGS) comprising a protective gas (SG) in at least one region of a beam path (BP) of THz radiation (TS1, TS2), In particular, said protective gas (SG) comprises at least one of the following elements or is formed from at least one of the following elements: a) dry air, b) dry gas, c) dry gas mixture, d) at least one gas that does not have an absorption line in the frequency range of THz radiation (TS1, TS2), In particular, said protective gas (SG) has a dew point temperature of less than or equal to -20°C, preferably less than or equal to -30°C, more preferably less than or equal to -40°C, In particular, said protective gas (SG) causes an attenuation of the THz radiation (TS1, TS2) along said beam path (BP), preferably of less than 0.1 dB for each frequency of the THz radiation (TS1, TS2), The THz device (100) according to at least one of the preceding clauses. (Additional note 18) a) at least one supply device (180) for at least temporarily supplying said protective gas flow (SGS), and / or b) The THz device (100) according to appendix 17, further comprising at least one pressure influencing member for influencing the pressure of the protective gas (SG). (Additional note 19) further comprising at least one nozzle (182); In particular, the nozzle (182) is designed and / or arranged to direct the protective gas flow (SGS) or at least a portion of the protective gas flow (SGS) into at least one region of the beam path (BP) of the THz radiation (TS1, TS2), In particular, said at least one nozzle (182) is a free jet nozzle. A THz device (100) according to at least one of supplementary items 17 to 18. (Additional note 20) The THz device (100) The THz device (100) a) to the object to be measured (OBJ), and / or b) for a target system in which the THz device (100) is placed, having at least one positioning unit (190) designed to move it at least temporarily, The THz device (100) according to at least one of the preceding clauses. (Additional note 21) The THz device (100) according to claim 20, wherein the THz device (100) is particularly designed to perform and / or enable closed-loop positioning based on data of the device (170) for determining aa) the position of the THz device (100) in space, and / or bb) the shape of a measurement object (OBJ), and / or cc) the distance between the THz device (100) and the measurement object (OBJ). (Additional note 22) A control device (200) for at least temporarily controlling the operation of at least one THz device (100) for transmitting and / or receiving terahertz (THz) radiation (TS1, TS2), In particular, the at least one THz device (100) is designed according to at least one of claims 1 to 19, in particular according to at least one of claims 10 to 19, the control device (200) has at least one first, in particular digital, interface (210) for data exchange, in particular bidirectional, with the THz device (100), In particular, the first interface (210) is wired or wireless; A control device (200). (Additional note 23) The control device (200) according to claim 22, wherein the control device (200) is designed to control the operation of multiple THz devices (100) simultaneously and / or at least partially in a time-overlapping manner and / or in a time-multiplexed manner. (Additional note 24) The control device (200) receives, via the first interface (210), The following signals: a) Clock signal (CLK), b) Trigger signal (TRIG), c) a data signal, in particular a data signal characterizing at least a portion of the THz signal to be received and / or transmitted; d) measurement data of a device (170) for determining aa) the position of the THz device (100) in space, and / or bb) the shape of a measurement object (OBJ), and / or cc) the distance between the THz device and the measurement object (OBJ); 24. The control device (200) according to at least one of appendixes 22 to 23, which is designed to transmit and / or receive at least one of the following: (Additional note 25) The control device (200) according to at least one of appendixes 22 to 24, wherein the control device (200) has at least one second interface (220) which is an optical interface for at least temporarily outputting the first pulsed laser radiation (PL1) and / or the second pulsed laser radiation (PL2) to at least one THz device (100). (Additional note 26) The control device (200) at least one laser device (230) for generating the first pulsed laser radiation (PL1) having a first pulse frequency and for generating the second pulsed laser radiation (PL2) having a second pulse frequency; In particular, the control device (200) according to at least one of supplementary items 22 to 25, wherein the second pulse frequency is at least temporarily different from the first pulse frequency. (Additional note 27) 27. The control device (200) according to claim 26, wherein the at least one laser device (230) comprises at least one, preferably two pulsed laser sources (230a, 230b), in particular femtosecond fs pulsed laser sources. (Additional note 28) The control device (200) according to at least one of appendix items 25 to 27, wherein the control device (200) is designed to at least temporarily output the first pulsed laser radiation (PL1) and / or the second pulsed laser radiation (PL2) to a plurality of THz devices (100), in particular simultaneously or at least partially overlapping in time or time-multiplexed. (Additional note 29) the control device (200) comprises at least one optical beam splitter (220') and / or an optical switch, in particular an optical switch for selectively supplying the first pulsed laser radiation (PL1) and / or the second pulsed laser radiation (PL2) to one or more THz devices (100); In particular, the optical beam splitter (220') and / or the optical switch are wavelength neutral and have a maximum attenuation of 1.0 dB, in particular 0.2 dB in the wavelength range between 1450 nm and 1650 nm, in particular between 1500 nm and 1600 nm; In particular, the optical beam splitter (220') and / or the optical switch: It is designed so that at least 80%, in particular 90% of the total power of the laser radiation (PL1, PL2) is transmitted in a wavelength range of + / - 100 nm, in particular + / - 50 nm around the central wavelength of the laser radiation (PL1, PL2); A control device (200) according to any one of supplementary items 25 to 28. (Additional note 30) a plurality of optical fiber devices (240) are provided for supplying the first pulsed laser radiation (PL1) and / or the second pulsed laser radiation (PL2) to the plurality of THz devices (100; 100_1, 100_2, 100_3); In particular, some, preferably each, of the plurality of light-guiding devices (240) are dispersion-matched and / or length-matched to a maximum optical path length difference of + / - 6 cm, in particular + / - 3 cm; A control device (200) according to at least one of supplementary items 25 to 29. (Additional note 31) The control device (200) according to at least one of supplementary items 26 to 30, wherein the at least one laser device (230) has at least one, preferably two, continuous wave laser sources or quasi-continuous wave laser sources. (Additional note 32) The control device (200) according to at least one of appendixes 26 to 31, wherein the control device (200) has at least one third interface (250) for the at least temporary electrical energy supply of at least one component of the at least one THz device (100). (Additional note 33) A control device (200) according to at least one of appendixes 22 to 32, wherein the control device (200) has at least one fourth interface (260) for data exchange, in particular bidirectional exchange, with at least one external component (10), e.g. a control computer. (Additional note 34) The control device (200) has at least one digital signal processing device (270); In particular, the control device (200) according to at least one of appendixes 22 to 32, wherein the at least one digital signal processing device (270) is designed to process at least one signal received by the at least one THz device (100). (Additional note 35) A system (1000) comprising at least one THz device (100) according to at least one of supplementary items 1 to 21, and at least one control device (200) according to at least one of supplementary items 22 to 34. (Additional note 36) A method of operating a terahertz THz device (100) for transmitting and / or receiving terahertz THz radiation (TS1, TS2), comprising at least one THz element (110) designed to transmit and / or receive (300) THz radiation (TS1, TS2) and a digital data processing device (120), comprising: The digital data processing device (120) at least temporarily processes (302) at least one first signal (S1, DS1) of at least one component (110) of the THz apparatus (100); method. (Additional note 37) 1. A method of operating a control device (200) for at least temporarily controlling the operation of at least one THz device (100) for transmitting and / or receiving terahertz (THz) radiation (TS1, TS2), comprising: In particular, the at least one THz device (100) is designed according to at least one of supplementary claims 1 to 21, in particular according to at least one of supplementary claims 10 to 21, the control device (200) has at least one first, in particular digital, interface (210) for data exchange, in particular bidirectional, with at least the THz device (100), In particular, the first interface (210) is wired or wireless; the control device (200) at least temporarily exchanges data (350) with at least one THz device (100), preferably with a plurality of THz devices (100), in particular for controlling the at least one THz device (100) or the plurality of THz devices (100); method. (Additional note 38) At least the following aspects of the THz device (100) according to at least one of supplementary claims 1 to 21 and / or the control device (200) according to at least one of supplementary claims 22 to 34 and / or the system (1000) according to supplementary claim 35 and / or the method according to at least one of supplementary claims 36 to 37: a) performing (402) a plurality of simultaneous and / or temporally offset and / or temporally alternating THz measurements, in particular with respect to at least one measurement object (OBJ); b) signal processing or pre-processing (404) of signals related to at least one THz signal (TS1, TS2), in particular by at least one THz device (100) and / or by at least one control device (200), c) centrally controlling (406) a plurality of THz devices (100_1, 100_2, 100_3) by said at least one control device; d) positioning (408) a plurality of THz devices (100; 100_1, 100_2, 100_3) under the control of said at least one control device, in particular by means of at least one positioning unit (190; 190a, 190b), e) performing a closed-loop positioning based in particular on data from a device (170) for determining aa) the position of the THz device (100) in space, and / or bb) the shape of a measurement object (OBJ), and / or cc) the distance between the THz device and the measurement object (OBJ); f1) measuring, in particular on a model basis, the layer thickness of several layers, in particular lacquer layers, located on top of one another, in particular where at least one of the layers is wet; f2) measuring, in particular on a model basis, the layer thickness of several layers, in particular lacquer layers, located on top of one another, in particular when at least one of the layers is dry; For use (400).

Claims

1. A system (1000) having at least one THz device (100) and at least one control device (200), A THz device (100) for transmitting and receiving THz radiation (TS1, TS2) comprises at least one THz element (110) designed to transmit and / or receive said THz radiation (TS1, TS2), the at least one THz element (110) is designed to detect at least one THz signal (TS2) and to output an output signal (AS) that characterizes the detected THz signal (TS2); The THz device (100) comprises a digitization stage (130) designed to convert the output signal (AS) of the at least one THz element (110) into a first digital signal (DS1), and a digital data processing device (120), said digital data processing device (120) is designed to at least temporarily process at least one first signal (S1, DS1) of at least one THz element (110) of said THz device (100); The THz device (100) has at least one first digital interface (140) for bidirectional data exchange (DA) with at least one external unit; the THz device (100) has at least one second interface (150) for at least a temporary electrical energy supply (EV) of the THz device (100); The THz device (100) is designed to receive at least two at least temporally distinct laser signals via a third interface (160) for at least one control device (200); the control device (200) has at least one first digital interface (210) for bidirectional data exchange with the at least one THz device (100) via the first digital interface (140) of the THz device (100); a second interface (220) of the control device (200) is provided for at least temporarily outputting a first pulsed laser radiation (PL1) and / or a second pulsed laser radiation (PL2) to the at least one THz device (100); the control device (200) is designed to at least temporarily control the operation of the at least one THz device (100); Terahertz System (1000).

2. The digitization stage (130) comprises an analog-to-digital converter (132) and at least one amplifier (134); The digital data processing device (120) comprises the following elements: a) a microprocessor; b) a microcontroller; c) a programmable logic module; d) Digital Signal Processor, DSP; e) Graphics Processor, GPU; The system (1000) of claim 1, comprising at least one of: f) an application specific integrated circuit, ASIC.

3. 2. The method of claim 1, wherein the digital data processing device is designed to at least temporarily control the operation of the THz device or at least one THz element and digitization stage of the THz device. System (1000).

4. The system (1000) of claim 1, wherein the digital data processing device (120) of the THz device (100) is at least temporarily controlled by at least one controller (200).

5. The system (1000) of claim 1 , wherein the digital data processing device (120) and / or the THz apparatus (100) are operated at least temporarily autonomously.

6. said THz device (100) and / or said digital data processing device (120) having at least one memory device (1204) for at least temporarily storing computer programs (PRG) and / or data (DAT); The data (DAT) includes the following elements: a) calibration data for at least one component of said THz device (100); b) model data characterizing at least one component of the THz device (100) or model data for at least one model of a component of the THz device (100); c) baseline measurement data; d) data characterizing at least a portion of the THz signal to be received and / or transmitted; The system (1000) of claim 1.

7. The digital data processing device (120) at least temporarily: a) background correction, b) pulse pile-up correction; c) filtering; d) averaging; e) Correction of THz data with reference measurements; f) providing a time domain signal and / or a frequency domain signal; g) data characterizing at least a portion of the THz signal to be received and / or transmitted.

8. The THz device (100) and / or at least one THz element (110) and digitization stage (130) of the THz device (100) receive, via the first digital interface (140), the following signals: a) at least one external unit or a clock signal (CLK) for synchronization with said at least one external unit; b) a trigger signal (TRIG); c) a data signal characterizing at least a portion of the THz signal to be received and / or transmitted; d) measurement data of a device (170) for determining aa) the position of the THz device (100) in space, and / or bb) the shape of a measurement object (OBJ), and / or cc) the distance between the THz device and the measurement object (OBJ); The system (1000) of claim 1, designed to transmit and / or receive at least one of:

9. The system (1000) of claim 1, wherein the first digital interface (140) is designed for two-way real-time communication.

10. The system (1000) of claim 1, wherein the at least one third interface (160) is an optical interface for at least temporarily receiving optical emissions (OS) from at least one control device (200).

11. The system (1000) of claim 1, wherein the at least one third interface (160) is an optical interface for at least temporarily receiving pulsed laser radiation (OS) from the at least one control device (200).

12. The THz device (100) a) the position of the THz device (100) in space, and / or b) the shape of the object to be measured (OBJ), and / or 2. The system (1000) of claim 1, comprising at least one device (170) for determining: c) a distance between the THz device (100) and the object to be measured (OBJ).

13. The THz device (100) The THz device (100) a) to the object to be measured (OBJ), and / or b) to a target system in which the THz device (100) is placed; having at least one positioning unit (190) designed to move it at least temporarily, The system (1000) of claim 1.

14. The system (1000) of claim 1, wherein the THz device (100) is designed to perform and / or enable closed-loop positioning based on data from a device (170) for determining aa) the position of the THz device (100) in space, and / or bb) the shape of a measurement object (OBJ), and / or cc) the distance between the THz device (100) and the measurement object (OBJ).

15. The system (1000) of claim 1, wherein the first digital interface (210) is wired or wireless, and / or the control device (200) is designed to control the operation of multiple THz devices (100) simultaneously and / or at least partially overlapping in time and / or in a time-multiplexed manner.

16. The control device (200) communicates with the digital interface (210) The following signals: a) a clock signal (CLK); b) a trigger signal (TRIG); c) a data signal characterizing at least a portion of the THz signal to be received and / or transmitted; d) measurement data of a device (170) for determining aa) the position of the THz device (100) in space, and / or bb) the shape of a measurement object (OBJ), and / or cc) the distance between the THz device and the measurement object (OBJ); The system (1000) of claim 1, designed to transmit and / or receive at least one of:

17. The system (1000) of claim 1, wherein the second interface (220) is an optical interface.

18. The control device (200) controls the first pulsed laser radiation ( 10. The system (1000) of claim 1, further comprising at least one laser device (230) for generating the second pulsed laser radiation (PL1) having a second pulse frequency and for generating the second pulsed laser radiation (PL2) having a second pulse frequency.

19. 20. The system (1000) of claim 18, wherein the second pulse frequency is at least temporarily different from the first pulse frequency.

20. 20. The system (1000) of claim 18, wherein the at least one laser device (230) comprises at least one pulsed laser source (230a, 230b).

21. The system (1000) of claim 1, wherein the control device (200) is designed to at least temporarily output the first pulsed laser radiation (PL1) and / or the second pulsed laser radiation (PL2) to multiple THz devices (100) simultaneously, at least partially overlapping in time, or time-multiplexed.

22. the control device (200) comprises at least one optical beam splitter (220′) and / or an optical switch for selectively supplying the first pulsed laser radiation (PL1) and / or the second pulsed laser radiation (PL2) to one or more THz devices (100); the optical beam splitter (220') and / or the optical switch are wavelength independent in the wavelength range between 1450 nm and 1650 nm and have a maximum attenuation of 1.0 dB; and / or The optical beam splitter (220') and / or the optical switch It is designed so that at least 80% of the total power of the laser radiation (PL1, PL2) is transmitted in a wavelength range of + / - 100 nm around the central wavelength of the pulsed laser radiation (PL1, PL2); The system (1000) of claim 1.

23. a plurality of optical fiber devices (240) are provided for supplying the first pulsed laser radiation (PL1) and / or the second pulsed laser radiation (PL2) to the plurality of THz devices (100; 100_1, 100_2, 100_3); each of the plurality of light guide devices (240) being dispersion-matched and / or length-matched to a maximum optical path length difference of + / - 6 cm; The system (1000) of claim 1.

24. the control device (200) has at least one third interface (250) for the at least temporary electrical energy supply of at least one component of the at least one THz device (100), and / or 2. The system (1000) of claim 1, wherein the control device (200) has at least one fourth interface (260) for bidirectional data exchange with at least one external component (10).

25. The control device (200) has at least one digital signal processing device (270); The system (1000) of claim 1, wherein the at least one digital signal processing device (270) is designed to process at least one signal received by the at least one THz device (100).

26. 2. The THz radiation (TS1, TS2) transmitter / receiver according to claim 1, which is designed to transmit and / or receive THz radiation (TS1, TS2) and has a digital data processing device (120). A method of operating a system (1000) for transmitting and receiving S2), comprising: The digital data processing device (120) at least temporarily processes (302) at least one first signal (S1, DS1) of at least one THz element (110) of the THz device (100); 17. The system of claim 16, wherein the control device comprises at least one first digital interface for bidirectional data exchange with the at least one THz device, The control device (200) at least temporarily exchanges data (350) with at least one THz device (100) for controlling a plurality of THz devices (100); method.

27. The system (1000) of claim 1, characterized in that at least the following aspects: a) performing (402) multiple simultaneous and / or time-offset and / or time-staggered THz measurements on at least one measurement object (OBJ); b) performing (404) signal processing or pre-processing of signals related to said at least one THz signal (TS1, TS2) by said at least one control device (200); c) centrally controlling (406) a plurality of THz devices (100_1, 100_2, 100_3) by said at least one control device; d) positioning (408) a plurality of THz devices (100; 100_1, 100_2, 100_3) under the control of said at least one control device by at least one positioning unit (190; 190a, 190b); e) performing closed-loop positioning based on data from a device (170) for determining aa) the position of the THz device (100) in space, and / or bb) the shape of a measurement object (OBJ), and / or cc) the distance between the THz device and the measurement object (OBJ); f1) model-based measurement of layer thicknesses of layers located on top of each other, at least one of the layers being wet; f2) model-based measurement of thicknesses of layers located on top of each other, at least one of the layers being dry; Use for (400).

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