EP2324389A1 - Terahertz radiation source and method for producing terahertz radiation - Google Patents
Terahertz radiation source and method for producing terahertz radiationInfo
- Publication number
- EP2324389A1 EP2324389A1 EP09779681A EP09779681A EP2324389A1 EP 2324389 A1 EP2324389 A1 EP 2324389A1 EP 09779681 A EP09779681 A EP 09779681A EP 09779681 A EP09779681 A EP 09779681A EP 2324389 A1 EP2324389 A1 EP 2324389A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- terahertz radiation
- laser
- terahertz
- pulse
- radiation source
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
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- 238000004611 spectroscopical analysis Methods 0.000 claims abstract description 9
- 239000000463 material Substances 0.000 claims abstract description 8
- 238000003384 imaging method Methods 0.000 claims abstract description 6
- 238000001228 spectrum Methods 0.000 claims description 10
- 238000001514 detection method Methods 0.000 claims description 7
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- CSJLBAMHHLJAAS-UHFFFAOYSA-N diethylaminosulfur trifluoride Substances CCN(CC)S(F)(F)F CSJLBAMHHLJAAS-UHFFFAOYSA-N 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 238000009659 non-destructive testing Methods 0.000 description 2
- 230000035939 shock Effects 0.000 description 2
- 229910004613 CdTe Inorganic materials 0.000 description 1
- 229910052691 Erbium Inorganic materials 0.000 description 1
- 229910001218 Gallium arsenide Inorganic materials 0.000 description 1
- 229910052769 Ytterbium Inorganic materials 0.000 description 1
- 229910007709 ZnTe Inorganic materials 0.000 description 1
- 230000000712 assembly Effects 0.000 description 1
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- JOXIMZWYDAKGHI-UHFFFAOYSA-N toluene-4-sulfonic acid Chemical compound CC1=CC=C(S(O)(=O)=O)C=C1 JOXIMZWYDAKGHI-UHFFFAOYSA-N 0.000 description 1
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Classifications
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/35—Non-linear optics
- G02F1/353—Frequency conversion, i.e. wherein a light beam is generated with frequency components different from those of the incident light beams
- G02F1/3534—Three-wave interaction, e.g. sum-difference frequency generation
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
- G01N21/35—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
- G01N21/3581—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light using far infrared light; using Terahertz radiation
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V8/00—Prospecting or detecting by optical means
- G01V8/005—Prospecting or detecting by optical means operating with millimetre waves, e.g. measuring the black losey radiation
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
- G01S13/88—Radar or analogous systems specially adapted for specific applications
- G01S13/887—Radar or analogous systems specially adapted for specific applications for detection of concealed objects, e.g. contraband or weapons
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F2203/00—Function characteristic
- G02F2203/13—Function characteristic involving THZ radiation
Definitions
- the present invention relates to a terahertz radiation source, an imaging and / or spectroscopy system, a method for generating terahertz radiation, a method for the detection and / or examination of living beings, objects and materials with such a system and the use of such a source and a such system.
- the electromagnetic spectrum can provide information about the complex chemical composition of substances as well as about the dielectric in the area of the terahertz frequency band
- the detection of explosives without direct contact is of particular interest.
- the corresponding sample is irradiated by a terahertz radiation source and the reflected, transmitted or scattered radiation is analyzed.
- An explosive spectral identification system may be based on a terahertz radiation source which generates terahertz radiation tunable within a wide frequency range and a broadband terahertz radiation detector.
- the spectral resolution is achieved in such a system by tuning the terahertz frequency and simultaneously recording the corresponding received intensity.
- time-domain spectroscopy which requires particularly broadband terahertz radiation sources, a narrow-band and tunable terahertz radiation source is needed for such a system.
- optical pulses of different frequency are generated by an optical parametric oscillator and converted into terahertz radiation by differential frequency generation in a nonlinear crystal, the terahertz frequency corresponding to the difference frequency of the pulses.
- optical parametric oscillators are extremely susceptible to temperature fluctuations and shocks.
- the terahertz radiation source comprising a pulsed femtosecond fiber laser, a pulse shaper, an optical amplifier, in particular fiber amplifier, and a nonlinear crystal whose laser, pulse shaper, optical amplifier and nonlinear crystal are designed and / or arranged such that a laser pulse generated by the laser first passes through the pulse shaper, then the optical amplifier and then the non-linear crystal, on the one hand has the advantage that all components have a lower susceptibility to interference, especially against temperature fluctuations and shocks.
- all components in the telecom band can be 1550 nm operated components, which in the long term can be manufactured at low unit cost, allowing for mass-market application.
- FIG. 1 shows a schematic block diagram of a terahertz radiation source according to the invention
- FIG. 2 is a graph illustrating the frequency domain of a laser pulse before and after passing through a pulse shaper having Gaussian filter characteristics.
- FIG. 1 shows that a terahertz radiation source according to the invention has a pulsed one
- Femtosecond fiber laser 1, a pulse shaper 2, an optical amplifier 3 and a nonlinear crystal 4 comprises. According to the invention, these are formed and / or arranged as shown in FIG. 1 such that a laser pulse I, II, III, IV generated by the laser 1 first passes through the pulse shaper 2, then the optical amplifier 3 and then the nonlinear crystal 4.
- a fiber laser is understood to be a solid-state laser whose laser-active medium forms a glass fiber, for example erbium, ytterbium and / or neodymium-doped glass fiber.
- a laser advantageously produces light with a high beam quality and has a robust construction, a high efficiency of the conversion process and a good cooling through the large surface of the fiber.
- a femtosecond fiber laser is understood to mean a fiber laser which generates laser pulses whose duration is in the femtosecond range.
- the femtosecond range is understood to be a range of> 50 fs to ⁇ 500 fs.
- a pulse shaper is understood to mean a device which converts a laser pulse I into a laser pulse II whose spectrum has at least two maxima at different frequencies and / or which transforms a laser pulse I into at least two laser pulses II of different frequencies.
- a pulse shaper is understood to mean a device which converts a laser pulse I into a laser pulse II whose spectrum has two maxima at different frequencies, or which converts a laser pulse I into two laser pulses II of different frequencies.
- pulse shapers such devices are also referred to as “pulse shapers.”
- the pulse shaper may or may not include optical components or assemblies for pulse expansion, pulse compression, or chirp compensation a temporal distortion of the pulses due to the dispersion properties of the optical components (fibers, prisms, etc.) understood.
- an optical amplifier is understood to mean a device which transmits an incoming optical signal of a wavelength or of a wavelength
- the optical amplifier can, but does not have to, contain optical components or modules for pulse expansion, pulse compression or chirp compensation.
- terahertz radiation By means of a terahertz radiation source according to the invention, narrow-band terahertz radiation which can be set within a wide frequency range can advantageously be generated.
- terahertz radiation is understood as meaning electromagnetic radiation in a range of> 15 ⁇ m to ⁇ 1000 ⁇ m.
- a narrowband terahertz radiation with a width of> 1 gigahertz to ⁇ 1 terahertz in particular from> 20 gigahertz to ⁇ 200 gigahertz be understood.
- a frequency range of> 0.3 terahertz to ⁇ 20 terahertz for example> 0.3 terahertz or> 0.5 terahertz or> 1 terahertz to ⁇ 3 terahertz or ⁇ 5 terahertz or ⁇ 10 terahertz, may be considered broad be understood.
- the optical amplifier 3 is a, for example erbium-doped, fiber amplifier.
- a fiber amplifier is understood to mean an optically pumped power amplifier for light signals conducted in optical fiber waveguides (optical waveguides).
- the fiber laser 1 generates laser pulses with a duration of> 50 fs to ⁇ 500 fs, for example of 100 fs.
- the central wavelength of the fiber laser 1 is in a range of> 1500 nm to ⁇ 1600 nm, for example> 1530 nm to ⁇ 1570.
- the central wavelength of the laser may be 1550 nm.
- the fiber laser 1 may be a double cladding fiber laser.
- the pulse shaper 2 can divide the laser pulse I both symmetrically and asymmetrically into at least two laser pulses II of different frequencies.
- a symmetrically dividing pulse shaper 2 can be used, for example.
- an asymmetrically dividing pulse shaper 2 can be used such that this counteracts the asymmetry of the laser pulse I generated by the fiber laser 1 due to its asymmetry.
- the pulse shaper 2 is a grating-based pulse shaper, a prism-based pulse shaper or a Mach-Zehnder interferometer with integrated Fabry-Perot filters.
- the Mach-Zehnder interferometer preferably comprises a first beam splitter (also called “beam splitter”), for example a first Y fiber coupler, for splitting the laser pulse I into a first and a second laser pulse, a first Fabry-Perot filter for filtering out a laser beam Frequency from the first laser pulse and a second Fabry-Perot filter for filtering out another frequency from the second laser pulse, and a second beam splitter (“Beamsplitter”), for example a second Y-fiber coupler, for superimposing the first and second laser pulses.
- a first beam splitter also called "beam splitter”
- Beamsplitter for example a second Y-fiber coupler
- a beam splitter is understood to mean a device which divides an incident light beam into two light beams or superimposes two incident light beams on it.
- a Y-fiber coupler is understood to be a component which divides a light signal located in a glass fiber into two glass fibers or superimposes the signals from two glass fibers in a single glass fiber.
- the original laser pulse I is split by the first beam splitter into two interferometer branches of the Mach-Zehnder interferometer. These two branches each contain a Fabry-Perot filter, which filters out one frequency from the laser spectrum. The two, for example, Lorentz-shaped, lines are then superimposed again in the second beam splitter and transmitted to the optical amplifier 3.
- the Fabry-Perot filters may be conventional Fabry-Perot filters, for example based on solid dielectric structures.
- the frequency difference between the two divided laser pulses can be adjusted, for example, by tilting the Fabry-Perot filters.
- the Fabry-Perot filters are microelectromechanical Fabry-Perot filters or MEMS resonators (MEMS: microelectromechanical system).
- MEMS microelectromechanical system
- the frequency difference between the two divided laser pulses can be adjusted for example by a, in particular electrically controlled, change in the distance between the mirror elements of the Fabry-Perot filter.
- the microelectromechanical Fabry-Perot filter can be integrated in a glass fiber element.
- the Mach-Zehnder interferometer comprises a first Y fiber coupler for dividing the laser pulse I into a first and a second laser pulse, a first microelectromechanical Fabry-Perot filter integrated in a fiber optic element to filter out a frequency from the first one Laser pulse and a second microelectromechanical Fabry-Perot filter integrated in a glass fiber element for filtering out another frequency from the second laser pulse, and a second Y fiber coupler for superimposing the first and second laser pulses.
- non-linear crystal for example, a DAST crystal (DAST: 4'-dimethylamino-N-methyl-4-stilbazolium tosylate), a ZnTe crystal, a CdTe crystal or a GaAs crystal can be used in the present invention.
- DAST crystal DAST: 4'-dimethylamino-N-methyl-4-stilbazolium tosylate
- ZnTe crystal ZnTe crystal
- CdTe crystal or a GaAs crystal can be used in the present invention.
- Another object of the present invention is a method for generating terahertz radiation with a terahertz radiation source according to the invention, which comprises the method steps:
- Generation of terahertz radiation IV - by difference frequency generation of the difference frequency f THz between the maxima at different frequencies of the amplified laser pulse III and / or by difference frequency generation of the difference frequency f THz between the different frequencies of the amplified laser pulses III, by the nonlinear crystal. 4 includes.
- a laser pulse I having a "wide frequency distribution” for example, a laser pulse with a frequency distribution of a width of> 5 THz to ⁇ 10 THz can be understood.
- the laser pulse I can be converted, for example, with a grating- or prism-based pulse shaper 2 into a laser pulse II whose spectrum has at least two maxima at different frequencies.
- a Mach-Zehnder interferometer with integrated Fabry-Perot filters As a pulse shaper 2, the laser pulse I can be converted into at least two laser pulses II of different frequencies.
- the frequency of the terahertz radiation IV can be adjusted by tuning the pulse shaper 2, in particular by tuning the difference frequency f THz .
- both the transformed laser pulses II and the amplified laser pulses III as shown in Figure 2, a symmetrical pulse shape.
- the spectral distribution III, in particular pulse shape, measured behind the optical amplifier 3 the necessary to achieve a symmetrical pulse shape III pulse shape II by a, not shown logic means, such as a microprocessor, calculated and set the pulse shaper 2 by an output of the logic means such be that this generates the necessary to achieve a symmetrical pulse shape III, in particular asymmetric, pulse shape II.
- This method according to the invention is therefore advantageously suitable for generating a narrow-band terahertz radiation which can be set within a wide frequency range.
- FIG. 1 shows that laser pulses I, for example with a duration in the range of 100 fs, are generated by the femtosecond fiber laser 1 within the scope of this method according to the invention.
- These laser pulses I are fed into a pulse shaper 2.
- the pulse shaper 2 in each case forms a laser pulse I into a laser pulse II whose spectrum has at least two maxima at different frequencies, and / or into at least two laser pulses II of different frequency.
- FIG. 2 shows the transformation of a laser pulse I with a Gauss-based pulse shaper in the frequency domain.
- FIG. 2 illustrates that from the laser pulse I generated by the fiber laser two spectral lines with the width ⁇ are selected by the pulse shaper 2 whose center frequencies differ from one another by the frequency f THz .
- FIG. 2 further shows that the two spectral lines are arranged symmetrically about the central, original laser wavelength I within the scope of the preferred embodiment shown. In the context of other embodiments according to the invention, however, it may also be an asymmetric distribution, in particular an asymmetric arrangement.
- the difference frequency f THz which corresponds to the frequency of the subsequently generated terahertz radiation IV, can be achieved by tuning the pulse shaper 2.
- Pulse shaper 2 After passing through the pulse shaper 2 are the through Pulse shaper 2 shaped pulse forms II in the optical amplifier 3, in particular fiber amplifier, where amplified that the electric field in the non-linear material of the nonlinear crystal 4 is sufficient to set a non-linear effect by the non-linear crystal 4 in motion.
- the amplified laser pulses III finally strike the nonlinear crystal 4, by means of which the terahertz radiation IV with the terahertz frequency f THz is generated by means of a nonlinear effect.
- the non-linear effect can be in particular difference frequency generation.
- the line width ⁇ of the terahertz radiation IV essentially corresponds to the width ⁇ of the two frequencies II filtered in the pulse shaper.
- the different frequency f THz and thus the frequency of the terahertz radiation IV can be varied within a very wide range.
- the minimum frequency of the terahertz radiation source according to the invention is given in approximation by the width ⁇ .
- the maximum frequency of the terahertz radiation source according to the invention results on the order of magnitude from the width of the original laser pulse I in the frequency domain.
- the present invention relates to an imaging and / or spectroscopy system, which comprises a terahertz radiation source according to the invention and a terahertz radiation sensor, which serves as a detector.
- the terahertz radiation source according to the invention and the terahertz radiation sensor with regard to the object to be examined can both be arranged such that the terahertz radiation sensor detects the radiation remaining after passing through the object as well as the terahertz radiation sensor detects the radiation reflected and / or scattered by the object.
- the terahertz radiation source, the terahertz radiation sensor, and the object may both be arranged along an axis, the object being located between the terahertz radiation source and the terahertz radiation sensor, as well as not being arranged along an axis.
- the system according to the invention advantageously enables real-time spectroscopy in the terahertz range as well as imaging detection in the terahertz range.
- One embodiment of the imaging and / or spectroscopy system according to the invention is a multispectral imaging and / or spectroscopy system which, in addition to the terahertz radiation sensor, has further radiation sensors, in particular sensors for radiation of the visible, near-infrared, and / or infrared range , includes.
- the present invention relates to a method for the detection and / or examination of living beings, in particular humans and animals, objects and materials, with a system according to the invention.
- this method can be based on frequency domain spectroscopy.
- the terahertz radiation source according to the invention radiates a narrow terahertz band in the method according to the invention, for example, with a width of> 1 gigahertz to ⁇ 1 terahertz, in particular from> 20 gigahertz to ⁇ 200 gigahertz, which is within a broad frequency range, for example in a range of> 0.3 terahertz to ⁇ 20 terahertz, for example> 0 , 3 terahertz or> 0.5 terahertz, or> 1 terahertz to ⁇ 3 terahertz or ⁇ 5 terahertz or ⁇ 10 terahertz, with the transmitted, reflected and / or scattered radiation through the, in particular broadband, terahe
- a terahertz radiation sensor is understood to mean, for example, a terahertz radiation sensor whose detection interval is> 0.3 terahertz to ⁇ 20 terahertz, in particular> 0.3 terahertz or> 0.5 terahertz or> 1 terahertz or> 1.5 terahertz to ⁇ 2.5 Terahertz or ⁇ 3 terahertz or ⁇ 5 terahertz or ⁇ 10 terahertz.
- the measurement result of the terahertz radiation sensor can be output in the context of this method according to the invention by an output device, for example a display, a screen or a printer.
- Terahertz radiation source a system according to the invention and / or a method according to the invention in surveillance / security technology, transportation, production, packaging, life science and / or medical field.
- the present invention relates to the use of a terahertz radiation source according to the invention, a system according to the invention and / or a method according to the invention for the detection and / or examination of living beings, in particular humans and animals, objects and materials, in particular explosives, for example at security checks at borders, in transit buildings, such as airports and railway stations, in means of transport, such as trains, buses, aircraft and / or ships, and / or at major events, for burglar-proofing of buildings, premises and means of transportation, for medical purposes and / or non-destructive testing of a workpiece ("non-destructive
- the terahertz radiation source according to the invention, the system according to the invention and / or the method according to the invention can be used in a multispectral camera for access control of sensitive sensors n Infrastructure
- Tissue be used.
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- General Health & Medical Sciences (AREA)
- Immunology (AREA)
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Abstract
The present invention relates to a terahertz radiation source comprising a pulsed femtosecond fiber laser (1), a pulse shaper (2), an optical amplifier (3) and a nonlinear crystal (4), wherein the laser (1), pulse shaper (2), optical amplifier (3) and nonlinear crystal (4) are adapted and/or disposed in such a way that a laser pulse I, II, III, IV produced by the laser (1) first passes through the pulse shaper (2), then the optical amplifier (3) and then the nonlinear crystal (4); an imaging and/or spectroscopy system; a method for generating terahertz radiation; a method for detecting and/or examining life forms, objects and materials using such a system; and use of such a source and such a system.
Description
Beschreibung description
Titeltitle
Terahertzstrahlungsquelle und Verfahren zur Erzeugung von TerahertzstrahlungTerahertz radiation source and method of generating terahertz radiation
Beschreibungdescription
Die vorliegende Erfindung betrifft eine Terahertzstrahlungsquelle, ein Bildgebungs- und/oder Spektroskopie-System, ein Verfahren zur Erzeugung von Terahertzstrahlung, ein Verfahren zur Detektion und/oder Untersuchung von Lebewesen, Gegenständen und Materialien mit einem derartigen System sowie die Verwendung einer derartigen Quelle und eines derartigen Systems.The present invention relates to a terahertz radiation source, an imaging and / or spectroscopy system, a method for generating terahertz radiation, a method for the detection and / or examination of living beings, objects and materials with such a system and the use of such a source and a such system.
Stand der TechnikState of the art
Das elektromagnetische Spektrum kann im Bereich des Terahertz-Frequenzbandes Informationen über die komplexe chemische Zusammensetzung von Stoffen, sowie über die dielektrischenThe electromagnetic spectrum can provide information about the complex chemical composition of substances as well as about the dielectric in the area of the terahertz frequency band
Eigenschaften von Gegenständen geben. In diesem Zusammenhang ist vor allem die Erkennung von Explosivstoffen ohne direkten Kontakt von Interesse. Hierbei wird die entsprechende Probe von einer Terahertzstrahlungsquelle angestrahlt und die reflektierte, transmittierte beziehungsweise gestreute Strahlung analysiert.Give properties of objects. In this context, the detection of explosives without direct contact is of particular interest. In this case, the corresponding sample is irradiated by a terahertz radiation source and the reflected, transmitted or scattered radiation is analyzed.
Ein System zur spektralen Identifikation von Explosivstoffen kann auf einer Terahertzstrahlungsquelle, welche eine innerhalb eines breiten Frequenzbereichs einstellbare Terahertzstrahlung erzeugt, und einem breitbandigen Terahertzstrahlungsdetektor basieren. Die spektrale Auflösung wird bei einem solchen System durch das Durchstimmen der Terahertzfrequenz und gleichzeitiges Aufzeichnen der entsprechenden empfangenen Intensität erreicht. Im Gegensatz zur Zeitdomänenspektroskopie, in der besonders breitbandige Terahertzstrahlungsquellen erforderlich sind, wird für ein derartiges System eine schmalbandige und durchstimmbare Terahertzstrahlungsquelle benötigt.An explosive spectral identification system may be based on a terahertz radiation source which generates terahertz radiation tunable within a wide frequency range and a broadband terahertz radiation detector. The spectral resolution is achieved in such a system by tuning the terahertz frequency and simultaneously recording the corresponding received intensity. In contrast to time-domain spectroscopy, which requires particularly broadband terahertz radiation sources, a narrow-band and tunable terahertz radiation source is needed for such a system.
Es ist bekannt, dass für eine derartige schmalbandige, abstimmbare Terahertzstrahlungsquelle nichtlineare optische Effekte, beispielsweise Differenzfrequenz-Generierung, genutzt werden können.
Um Differenzfrequenz-Generierung ausnutzen zu können, werden jedoch mindestens zwei optische Impulse unterschiedlicher Frequenz benötigt.It is known that nonlinear optical effects, such as difference frequency generation, can be used for such a narrow-band, tunable terahertz radiation source. In order to exploit difference frequency generation, however, at least two optical pulses of different frequency are required.
Herkömmlicherweise werden derartige optische Impulse unterschiedlicher Frequenz durch einen optischen parametrischen Oszillator erzeugt und durch Differenzfrequenz-Generierung in einem nichtlinearen Kristall in Terahertzstrahlung umgewandelt, wobei die Terahertzfrequenz der Differenzfrequenz der Impulse entspricht. Problematisch ist hierbei jedoch, dass optische parametrische Oszillatoren äußerst anfällig gegen Temperaturschwankungen und Stöße sind.Conventionally, such optical pulses of different frequency are generated by an optical parametric oscillator and converted into terahertz radiation by differential frequency generation in a nonlinear crystal, the terahertz frequency corresponding to the difference frequency of the pulses. However, the problem here is that optical parametric oscillators are extremely susceptible to temperature fluctuations and shocks.
Offenbarung der ErfindungDisclosure of the invention
Vorteile der ErfindungAdvantages of the invention
Die erfindungsgemäße Terahertzstrahlungsquelle, umfassend einen gepulsten Femtosekunden-Faserlaser, einen Pulsformer, einen optischen Verstärker, insbesondere Faserverstärker, und einen nichtlinearen Kristall, deren Laser, Pulsformer, optischer Verstärker und nichtlinearer Kristall derart ausgebildet und/oder angeordnet sind, dass ein vom Laser erzeugter Laserpuls erst den Pulsformer, dann den optischen Verstärker und dann den nichtlinearen Kristall durchläuft, hat zum einen den Vorteil, dass alle Komponenten eine geringere Störungsanfälligkeit, insbesondere gegenüber Temperaturschwankungen und Stößen aufweisen. Darüber hinaus können alle Komponenten im Telekom-Band bei 1550 nm betriebene Komponenten sein, welche langfristig betrachtet zu niedrigen Produktionsstückkosten hergestellt werden können, was eine Anwendung in Massenprodukten ermöglicht.The terahertz radiation source according to the invention, comprising a pulsed femtosecond fiber laser, a pulse shaper, an optical amplifier, in particular fiber amplifier, and a nonlinear crystal whose laser, pulse shaper, optical amplifier and nonlinear crystal are designed and / or arranged such that a laser pulse generated by the laser first passes through the pulse shaper, then the optical amplifier and then the non-linear crystal, on the one hand has the advantage that all components have a lower susceptibility to interference, especially against temperature fluctuations and shocks. In addition, all components in the telecom band can be 1550 nm operated components, which in the long term can be manufactured at low unit cost, allowing for mass-market application.
Zeichnungendrawings
Weitere Vorteile und vorteilhafte Ausgestaltungen des erfindungsgemäßen Gegenstandes werden durch die Zeichnungen veranschaulicht und in der nachfolgenden Beschreibung erläutert. Dabei ist zu beachten, dass die Figuren nur beschreibenden Charakter haben und nicht dazu gedacht sind, die Erfindung in irgendeiner Form einzuschränken. Es zeigen:
Fig. 1 ein schematisches Blockschaltbild einer erfindungsgemäßen Terahertzstrahlungsquelle; und Fig. 2 einen Graphen zur Veranschaulichung der Frequenzdomaine eines Laserpulses vor und nach dem Durchlaufen eines Pulsformers mit Gauß-förmigen Filtereigenschaften.Further advantages and advantageous embodiments of the subject invention are illustrated by the drawings and explained in the following description. It should be noted that the figures have only descriptive character and are not intended to limit the invention in any way. Show it: 1 shows a schematic block diagram of a terahertz radiation source according to the invention; and FIG. 2 is a graph illustrating the frequency domain of a laser pulse before and after passing through a pulse shaper having Gaussian filter characteristics.
Figur 1 zeigt, dass eine erfindungsgemäße Terahertzstrahlungsquelle einen gepulstenFIG. 1 shows that a terahertz radiation source according to the invention has a pulsed one
Femtosekunden-Faserlaser 1, einen Pulsformer 2, einen optischen Verstärker 3 und einen nichtlinearen Kristall 4 umfasst. Erfindungsgemäß sind diese, wie in Figur 1 gezeigt derart ausgebildet und/oder angeordnet, dass ein vom Laser 1 erzeugter Laserpuls I, II, III, IV erst den Pulsformer 2, dann den optischen Verstärker 3 und dann den nichtlinearen Kristall 4 durchläuft.Femtosecond fiber laser 1, a pulse shaper 2, an optical amplifier 3 and a nonlinear crystal 4 comprises. According to the invention, these are formed and / or arranged as shown in FIG. 1 such that a laser pulse I, II, III, IV generated by the laser 1 first passes through the pulse shaper 2, then the optical amplifier 3 and then the nonlinear crystal 4.
Unter einem Faserlaser wird im Rahmen der vorliegenden Erfindung ein Festkörperlaser verstanden, dessen laseraktives Medium eine, beispielsweise Erbium-, Ytterbium- und/oder Neodym-dotierter, Glasfaser bildet. Ein derartiger Laser erzeugt vorteilhafterweise Licht mit einer hohen Strahlqualität und weist einen robusten Aufbau, eine hohe Effizienz des Konversionsprozesses und eine gute Kühlung durch die große Oberfläche der Faser auf.In the context of the present invention, a fiber laser is understood to be a solid-state laser whose laser-active medium forms a glass fiber, for example erbium, ytterbium and / or neodymium-doped glass fiber. Such a laser advantageously produces light with a high beam quality and has a robust construction, a high efficiency of the conversion process and a good cooling through the large surface of the fiber.
Unter einem Femtosekunden-Faserlaser wird im Rahmen der vorliegenden Erfindung ein Faserlaser verstanden, der Laserpulse erzeugt, deren Dauer im Femtosekunden-Bereich liegt. Dabei wird unter dem Femtosekundenbereich ein Bereich von > 50 fs bis < 500 fs verstanden.In the context of the present invention, a femtosecond fiber laser is understood to mean a fiber laser which generates laser pulses whose duration is in the femtosecond range. In this case, the femtosecond range is understood to be a range of> 50 fs to <500 fs.
Unter einem Pulsformer wird im Rahmen der vorliegenden Erfindung eine Vorrichtung verstanden, welche einen Laserpuls I in einen Laserimpuls II umformt, dessen Spektrum mindestens zwei Maxima bei unterschiedlichen Frequenzen aufweist, und/oder welche einen Laserpuls I in mindestens zwei Laserpulse II unterschiedlicher Frequenz umformt. Beispielsweise wird unter einem Pulsformer eine Vorrichtung verstanden, welche einen Laserpuls I in einen Laserimpuls II umformt, dessen Spektrum zwei Maxima bei unterschiedlichen Frequenzen aufweist, oder welche einen Laserpuls I in zwei Laserpulse II unterschiedlicher Frequenz umformt. Derartige Vorrichtungen werden unter anderem auch als „Pulse-Shaper" bezeichnet. Der Pulsformer kann, muss aber nicht, optische Bauelemente beziehungsweise Baugruppen zur Impulsaufweitung, zur Impulskompression oder zur Kompensation von Chirp enthalten. Unter dem Begriff „Chirp" wird im Rahmen der vorliegenden Erfindung eine zeitliche Verzerrung der Impulse aufgrund der Dispersioneigenschaften der optischen Bauelemente (Fasern, Prismen, etc.) verstanden.In the context of the present invention, a pulse shaper is understood to mean a device which converts a laser pulse I into a laser pulse II whose spectrum has at least two maxima at different frequencies and / or which transforms a laser pulse I into at least two laser pulses II of different frequencies. For example, a pulse shaper is understood to mean a device which converts a laser pulse I into a laser pulse II whose spectrum has two maxima at different frequencies, or which converts a laser pulse I into two laser pulses II of different frequencies. Among other things, such devices are also referred to as "pulse shapers." The pulse shaper may or may not include optical components or assemblies for pulse expansion, pulse compression, or chirp compensation a temporal distortion of the pulses due to the dispersion properties of the optical components (fibers, prisms, etc.) understood.
Unter einem optischen Verstärker wird im Rahmen der vorliegenden Erfindung eine Vorrichtung verstanden, welche ein eingehendes optisches Signal einer Wellenlänge oder einesIn the context of the present invention, an optical amplifier is understood to mean a device which transmits an incoming optical signal of a wavelength or of a wavelength
Wellenlängenbereichs verstärkt und als optisches Signal der gleichen Wellenlänge beziehungsweise des gleichen Wellenlängenbereiches weitergibt. Der optische Verstärker kann, muss aber nicht,
optische Bauelemente beziehungsweise Baugruppen zur Impulsaufweitung, zur Impulskompression oder zur Kompensation von Chirp enthalten.Amplified wavelength range and passes as an optical signal of the same wavelength or the same wavelength range. The optical amplifier can, but does not have to, contain optical components or modules for pulse expansion, pulse compression or chirp compensation.
Durch eine erfindungsgemäße Terahertzstrahlungsquelle kann vorteilhafterweise schmalbandige, innerhalb eines breiten Frequenzbereichs einstellbare Terahertzstrahlung erzeugt werden. Dabei wird im Rahmen der vorliegenden Erfindung unter Terahertzstrahlung elektromagnetische Strahlung in einem Bereich von > 15 μm bis < 1000 μm verstanden. Als schmalbandig kann eine Terahertzstrahlung mit einer Breite von > 1 Gigahertz bis < 1 Terahertz, insbesondere von > 20 Gigahertz bis < 200 Gigahertz, verstanden werden. Ein Frequenzbereich von > 0,3 Terahertz bis < 20 Terahertz, beispielsweise von > 0,3 Terahertz oder von > 0,5 Terahertz oder von > 1 Terahertz bis < 3 Terahertz oder bis < 5 Terahertz oder bis < 10 Terahertz, kann als breit verstanden werden.By means of a terahertz radiation source according to the invention, narrow-band terahertz radiation which can be set within a wide frequency range can advantageously be generated. In the context of the present invention, terahertz radiation is understood as meaning electromagnetic radiation in a range of> 15 μm to <1000 μm. As a narrowband terahertz radiation with a width of> 1 gigahertz to <1 terahertz, in particular from> 20 gigahertz to <200 gigahertz be understood. A frequency range of> 0.3 terahertz to <20 terahertz, for example> 0.3 terahertz or> 0.5 terahertz or> 1 terahertz to <3 terahertz or <5 terahertz or <10 terahertz, may be considered broad be understood.
Im Rahmen einer bevorzugten Ausführungsform der Erfindung ist der optische Verstärker 3 ein, beispielsweise Erbium- dotierter, Faserverstärker. Dabei wird unter einem Faserverstärker im Rahmen der vorliegenden Erfindung ein optisch gepumpter Leistungsverstärker für in Glasfaser- Lichtwellenleitern (Lichtleiter) geführte Lichtsignale verstanden.Within the scope of a preferred embodiment of the invention, the optical amplifier 3 is a, for example erbium-doped, fiber amplifier. In the context of the present invention, a fiber amplifier is understood to mean an optically pumped power amplifier for light signals conducted in optical fiber waveguides (optical waveguides).
Im Rahmen einer weiteren bevorzugten Ausführungsform der Erfindung erzeugt der Faserlaser 1 Laserpulse mit einer Dauer von > 50 fs bis < 500 fs, beispielsweise von 100 fs.Within the scope of a further preferred embodiment of the invention, the fiber laser 1 generates laser pulses with a duration of> 50 fs to <500 fs, for example of 100 fs.
Im Rahmen einer weiteren bevorzugten Ausführungsform der Erfindung liegt die Zentralwellenlänge des Faserlasers 1 in einem Bereich von > 1500 nm bis < 1600 nm, beispielsweise von > 1530 nm bis < 1570. Beispielsweise kann die Zentralwellenlänge des Lasers 1550 nm betragen. Ferner kann es sich bei dem Faserlaser 1 um einen Doppelmantelfaserlaser handeln.Within the scope of a further preferred embodiment of the invention, the central wavelength of the fiber laser 1 is in a range of> 1500 nm to <1600 nm, for example> 1530 nm to <1570. For example, the central wavelength of the laser may be 1550 nm. Furthermore, the fiber laser 1 may be a double cladding fiber laser.
Im Rahmen der vorliegenden Erfindung kann der Pulsformer 2 den Laserpuls I sowohl symmetrisch als auch asymmetrisch in mindestens zwei Laserpulse II unterschiedlicher Frequenz aufteilen. Insofern der von dem Faserlaser 1 erzeugte Laserpuls I symmetrisch ist, kann beispielsweise ein symmetrisch teilender Pulsformer 2 eingesetzt werden. Insofern der von dem Faserlaser 1 erzeugten Laserpuls I asymmetrisch ist, kann vorteilhafterweise ein asymmetrisch teilender Pulsformer 2 derart eingesetzt werden, dass dieser durch seine Asymmetrie die Asymmetrie des von dem Faserlaser 1 erzeugten Laserpuls I aufhebt.In the context of the present invention, the pulse shaper 2 can divide the laser pulse I both symmetrically and asymmetrically into at least two laser pulses II of different frequencies. Inasmuch as the laser pulse I generated by the fiber laser 1 is symmetrical, a symmetrically dividing pulse shaper 2 can be used, for example. Inasmuch as the laser pulse I generated by the fiber laser 1 is asymmetrical, advantageously an asymmetrically dividing pulse shaper 2 can be used such that this counteracts the asymmetry of the laser pulse I generated by the fiber laser 1 due to its asymmetry.
Im Rahmen einer weiteren bevorzugten Ausführungsform der Erfindung ist der Pulsformer 2 ein Gitter-basierter Pulsformer, ein Prismen-basierter Pulsformer oder ein Mach-Zehnder-Interferometer mit integrierten Fabry-Perot-Filtern.
Vorzugsweise umfasst das Mach-Zehnder-Interferometer dabei einen ersten Strahlenteiler (auch „Beamsplitter" genannt), beispielsweise einen ersten Y-Faserkoppler, zum Teilen des Laserpulses I in einen ersten und einen zweiten Laserpuls, einen ersten Fabry-Perot-Filter zum Herausfiltern einer Frequenz aus dem ersten Laserpuls und einen zweiten Fabry-Perot-Filter zum Herausfiltern einer anderen Frequenz aus dem zweiten Laserpuls, und einen zweiten Strahlenteiler („Beamsplitter"), beispielsweise einen zweiten Y-Faserkoppler, zum Überlagern des ersten und zweiten Laserpulses.Within the scope of a further preferred embodiment of the invention, the pulse shaper 2 is a grating-based pulse shaper, a prism-based pulse shaper or a Mach-Zehnder interferometer with integrated Fabry-Perot filters. In this case, the Mach-Zehnder interferometer preferably comprises a first beam splitter (also called "beam splitter"), for example a first Y fiber coupler, for splitting the laser pulse I into a first and a second laser pulse, a first Fabry-Perot filter for filtering out a laser beam Frequency from the first laser pulse and a second Fabry-Perot filter for filtering out another frequency from the second laser pulse, and a second beam splitter ("Beamsplitter"), for example a second Y-fiber coupler, for superimposing the first and second laser pulses.
Unter einem Strahlenteiler wird im Rahmen der vorliegenden Erfindung eine Vorrichtung verstanden, die einen einfallenden Lichtstrahl in zwei Lichtstrahlen aufteilt beziehungsweise zwei einfallende Lichtstrahlen überlagert. Unter einem Y-Faserkoppler wird im Rahmen der vorliegenden Erfindung ein Bauelement verstanden, das ein in einer Glasfaser befindliches Lichtsignal auf zwei Glasfasern aufteilt beziehungsweise die Signale aus zwei Glasfasern in einer einzigen Glasfaser überlagert.In the context of the present invention, a beam splitter is understood to mean a device which divides an incident light beam into two light beams or superimposes two incident light beams on it. In the context of the present invention, a Y-fiber coupler is understood to be a component which divides a light signal located in a glass fiber into two glass fibers or superimposes the signals from two glass fibers in a single glass fiber.
In einem derartigen Mach-Zehnder-Interferometer wird der ursprüngliche Laserpuls I durch den ersten Strahlenteiler in zwei Interferometerzweige des Mach-Zehnder-Interferometers aufgeteilt. In diesen beiden Zweigen befindet sich je ein Fabry-Perot-Filter, der jeweils eine Frequenz aus dem Laserspektrum herausfiltert. Die beiden, beispielsweise Lorentz- förmigen, Linien werden anschließend im zweiten Strahlenteiler wieder überlagert und an den optischen Verstärker 3 übermittelt.In such a Mach-Zehnder interferometer, the original laser pulse I is split by the first beam splitter into two interferometer branches of the Mach-Zehnder interferometer. These two branches each contain a Fabry-Perot filter, which filters out one frequency from the laser spectrum. The two, for example, Lorentz-shaped, lines are then superimposed again in the second beam splitter and transmitted to the optical amplifier 3.
Bei den Fabry-Perot-Filtern kann es sich dabei um herkömmliche Fabry-Perot-Filter, beispielsweise auf der Basis fester dielektrischer Strukturen, handeln. In diesem Fall kann die Frequenzdifferenz zwischen den beiden geteilten Laserpulsen beispielsweise durch Verkippen der Fabry-Perot-Filter eingestellt werden.The Fabry-Perot filters may be conventional Fabry-Perot filters, for example based on solid dielectric structures. In this case, the frequency difference between the two divided laser pulses can be adjusted, for example, by tilting the Fabry-Perot filters.
Im Rahmen einer besonders bevorzugten Ausführungsform der Erfindung handelt es sich bei den Fabry-Perot-Filtern um mikroelektromechanische Fabry-Perot-Filter beziehungsweise MEMS- Resonatoren (MEMS: microelectro mechanical System). In diesem Fall kann die Frequenzdifferenz zwischen den beiden geteilten Laserpulsen beispielsweise durch eine, insbesondere elektrisch gesteuerte, Änderung des Abstands zwischen den Spiegelelementen des Fabry-Perot-Filters eingestellt werden.In a particularly preferred embodiment of the invention, the Fabry-Perot filters are microelectromechanical Fabry-Perot filters or MEMS resonators (MEMS: microelectromechanical system). In this case, the frequency difference between the two divided laser pulses can be adjusted for example by a, in particular electrically controlled, change in the distance between the mirror elements of the Fabry-Perot filter.
Der mikroelektromechanische Fabry-Perot-Filter kann dabei in einem Glasfaserelement integriert sein. Beispielsweise umfasst das Mach-Zehnder-Interferometer im Rahmen einer Ausführungsform einen ersten Y-Faserkoppler zum Teilen des Laserpulses I in einen ersten und einen zweiten Laserpuls, einen ersten mikroelektromechanischen, in ein Glasfaserelement integrierten Fabry-Perot- Filter zum Herausfiltern einer Frequenz aus dem ersten Laserpuls und einen zweiten
mikroelektromechanischen, in ein Glasfaserelement integrierten Fabry-Perot-Filter zum Herausfiltern einer anderen Frequenz aus dem zweiten Laserpuls, und einen zweiten Y-Faserkoppler zum Überlagern des ersten und zweiten Laserpulses.The microelectromechanical Fabry-Perot filter can be integrated in a glass fiber element. For example, in one embodiment, the Mach-Zehnder interferometer comprises a first Y fiber coupler for dividing the laser pulse I into a first and a second laser pulse, a first microelectromechanical Fabry-Perot filter integrated in a fiber optic element to filter out a frequency from the first one Laser pulse and a second microelectromechanical Fabry-Perot filter integrated in a glass fiber element for filtering out another frequency from the second laser pulse, and a second Y fiber coupler for superimposing the first and second laser pulses.
Als nichtlinearer Kristall kann im Rahmen der vorliegenden Erfindung beispielsweise ein DAST- Kristall (DAST: 4'-dimethylamino-N-methyl-4-stilbazolium tosylate), ein ZnTe-Kristall, ein CdTe- Kristall oder ein GaAs-Kristall verwendet werden.As the non-linear crystal, for example, a DAST crystal (DAST: 4'-dimethylamino-N-methyl-4-stilbazolium tosylate), a ZnTe crystal, a CdTe crystal or a GaAs crystal can be used in the present invention.
Ein weiterer Gegenstand der vorliegenden Erfindung ist ein Verfahren zum Erzeugen von Terahertzstrahlung mit einer erfmdungsgemäßen Terahertzstrahlungsquelle, welches die Verfahrensschritte :Another object of the present invention is a method for generating terahertz radiation with a terahertz radiation source according to the invention, which comprises the method steps:
1. Erzeugen eines Laserpulses I, insbesondere mit einer breiten Frequenzverteilung, durch den Laser 1,1. generating a laser pulse I, in particular with a wide frequency distribution, by the laser 1,
2. Umformen des Laserpulses I - in einen Laserimpuls II, dessen Spektrum mindestens zwei Maxima bei unterschiedlichen Frequenzen aufweist, und/oder in mindestens zwei Laserpulse II unterschiedlicher Frequenz, durch den Pulsformer 2;2. Forming the laser pulse I - in a laser pulse II, the spectrum of which has at least two maxima at different frequencies, and / or in at least two laser pulses II of different frequency, by the pulse shaper 2;
3. Verstärken - des Laserpulses II, dessen Spektrum mindestens zwei Maxima bei unterschiedlichen Frequenzen aufweist, zu einem verstärkten Laserpuls III, und/oder der Laserpulse II unterschiedlicher Frequenz zu verstärkten Laserpulsen III, durch den optischen Verstärker 3, und3. amplifying - the laser pulse II whose spectrum has at least two maxima at different frequencies, to an amplified laser pulse III, and / or the laser pulses II of different frequency to amplified laser pulses III, through the optical amplifier 3, and
4. Erzeugen von Terahertzstrahlung IV - durch Differenzfrequenz-Generierung der Differenzfrequenz fTHz zwischen den Maxima bei unterschiedlichen Frequenzen des verstärkten Laserimpulses III und/oder durch Differenzfrequenz-Generierung der Differenzfrequenz fTHz zwischen den unterschiedlichen Frequenzen der verstärkten Laserimpulse III, durch den nichtlinearen Kristall 4, umfasst.4. Generation of terahertz radiation IV - by difference frequency generation of the difference frequency f THz between the maxima at different frequencies of the amplified laser pulse III and / or by difference frequency generation of the difference frequency f THz between the different frequencies of the amplified laser pulses III, by the nonlinear crystal. 4 , includes.
Unter einem Laserpuls I mit einer „breiten Frequenzverteilung" kann beispielsweise ein Laserpuls mit einer Frequenzverteilung einer Breite von > 5 THz bis < 10 THz verstanden werden.By a laser pulse I having a "wide frequency distribution", for example, a laser pulse with a frequency distribution of a width of> 5 THz to <10 THz can be understood.
Der Laserpuls I kann beispielsweise mit einem Gitter- oder Prismen-basierten Pulsformer 2 in einen Laserimpuls II umgeformt werden, dessen Spektrum mindestens zwei Maxima bei unterschiedlichen Frequenzen aufweist. Durch ein Mach-Zehnder-Interferometer mit integrierten Fabry-Perot-Filtern
als Pulsformer 2 kann der Laserpuls I in mindestens zwei Laserpulse II unterschiedlicher Frequenz umgeformt werden.The laser pulse I can be converted, for example, with a grating- or prism-based pulse shaper 2 into a laser pulse II whose spectrum has at least two maxima at different frequencies. Through a Mach-Zehnder interferometer with integrated Fabry-Perot filters As a pulse shaper 2, the laser pulse I can be converted into at least two laser pulses II of different frequencies.
Die Frequenz der Terahertzstrahlung IV kann durch Durchstimmen des Pulsformers 2, insbesondere durch Durchstimmen der Differenzfrequenz fTHz, eingestellt werden.The frequency of the terahertz radiation IV can be adjusted by tuning the pulse shaper 2, in particular by tuning the difference frequency f THz .
Vorzugsweise weisen sowohl die umgeformten Laserpulse II als auch die verstärkten Laserpulse III, wie in Figur 2 gezeigt, eine symmetrische Pulsform auf. Durch etwaige Nichtlinearitäten des optischen Verstärkers 3 auftretende Verzerrungen der Pulsform können durch eine entsprechende Anpassung der in den optischen Verstärker 3 eingespeisten Pulsform II durch den Pulsformer 2 ausgeglichen werden. Beispielsweise kann die spektrale Verteilung III, insbesondere Pulsform, hinter dem optischen Verstärker 3 gemessen, die zum Erzielen einer symmetrischen Pulsform III erforderliche Pulsform II durch ein, nicht dargestelltes Logikmittel, beispielsweise einen Mikroprozessor, berechnet und der Pulsformer 2 durch eine Ausgabe des Logikmittels derart eingestellt werden, dass dieser die zum Erzielen einer symmetrischen Pulsform III erforderliche, insbesondere asymmetrische, Pulsform II generiert.Preferably, both the transformed laser pulses II and the amplified laser pulses III, as shown in Figure 2, a symmetrical pulse shape. By any nonlinearities of the optical amplifier 3 occurring distortions of the pulse shape can be compensated by a corresponding adjustment of the fed into the optical amplifier 3 pulse shape II by the pulse shaper 2. For example, the spectral distribution III, in particular pulse shape, measured behind the optical amplifier 3, the necessary to achieve a symmetrical pulse shape III pulse shape II by a, not shown logic means, such as a microprocessor, calculated and set the pulse shaper 2 by an output of the logic means such be that this generates the necessary to achieve a symmetrical pulse shape III, in particular asymmetric, pulse shape II.
Dieses erfindungsgemäße Verfahren ist daher vorteilhafterweise zum Erzeugen einer schmalbandigen, innerhalb eines breiten Frequenzbereichs einstellbaren Terahertzstrahlung geeignet.This method according to the invention is therefore advantageously suitable for generating a narrow-band terahertz radiation which can be set within a wide frequency range.
Figur 1 zeigt, dass im Rahmen dieses erfindungsgemäßen Verfahrens von dem Femtosekunden- Faserlaser 1 Laserpulse I, beispielsweise mit einer Dauer im Bereich von 100 fs erzeugt werden. Diese Laserpulse I werden in einen Pulsformer 2 eingespeist. Der Pulsformer 2 formt jeweils einen Laserpuls I in einen Laserimpuls II, dessen Spektrum mindestens zwei Maxima bei unterschiedlichen Frequenzen aufweist, und/oder in mindestens zwei Laserpulse II unterschiedlicher Frequenz um.FIG. 1 shows that laser pulses I, for example with a duration in the range of 100 fs, are generated by the femtosecond fiber laser 1 within the scope of this method according to the invention. These laser pulses I are fed into a pulse shaper 2. The pulse shaper 2 in each case forms a laser pulse I into a laser pulse II whose spectrum has at least two maxima at different frequencies, and / or into at least two laser pulses II of different frequency.
Ein derartiges Umformen eines Laserpulses I wird in Figur 2 veranschaulicht. Figur 2 zeigt dabei die Umformung eines Laserpulses I mit einem Gauß-basierten Pulsformer in der Frequenzdomaine.Such reshaping of a laser pulse I is illustrated in FIG. FIG. 2 shows the transformation of a laser pulse I with a Gauss-based pulse shaper in the frequency domain.
Figur 2 veranschaulicht, dass aus dem von dem Faserlaser erzeugte Laserpuls I zwei Spektrallinien mit der Breite γ durch den Pulsformer 2 selektiert werden, deren Zentralfrequenzen sich durch die Frequenz fTHz voneinander unterscheidet. Figur 2 zeigt ferner, dass die beiden Spektrallinien im Rahmen der gezeigten, bevorzugten Ausführungsform um die zentrale, ursprüngliche Laserwellenlänge I symmetrisch angeordnet sind. Im Rahmen anderer erfindungsgemäßer Ausführungsformen kann es sich jedoch auch um eine asymmetrische Verteilung, insbesondere asymmetrische Anordnung, handeln. Die Differenzfrequenz fTHz, welche der Frequenz der anschließend erzeugten Terahertzstrahlung IV entspricht, kann mittels Durchstimmen des Pulsformers 2 erreicht werden. Nach dem Durchlaufen des Pulsformers 2 werden die durch den
Pulsformer 2 gestalteten Pulsformen II im optischen Verstärker 3, insbesondere Faserverstärker, soweit verstärkt, dass das elektrische Feld im nichtlinearen Material des nichtlinearen Kristalls 4 ausreicht, um einen nichtlinearen Effekt durch den nichtlinearen Kristall 4 in Gang zu setzen. Die verstärkten Laserpulse III treffen schließlich auf den nichtlinearen Kristall 4, durch welchen mittels eines nichtlinearen Effekts die Terahertzstrahlung IV mit der Terahertzfrequenz fTHz erzeugt wird. Der nichtlineare Effekt kann dabei insbesondere Differenzfrequenz-Generierung sein.FIG. 2 illustrates that from the laser pulse I generated by the fiber laser two spectral lines with the width γ are selected by the pulse shaper 2 whose center frequencies differ from one another by the frequency f THz . FIG. 2 further shows that the two spectral lines are arranged symmetrically about the central, original laser wavelength I within the scope of the preferred embodiment shown. In the context of other embodiments according to the invention, however, it may also be an asymmetric distribution, in particular an asymmetric arrangement. The difference frequency f THz , which corresponds to the frequency of the subsequently generated terahertz radiation IV, can be achieved by tuning the pulse shaper 2. After passing through the pulse shaper 2 are the through Pulse shaper 2 shaped pulse forms II in the optical amplifier 3, in particular fiber amplifier, where amplified that the electric field in the non-linear material of the nonlinear crystal 4 is sufficient to set a non-linear effect by the non-linear crystal 4 in motion. The amplified laser pulses III finally strike the nonlinear crystal 4, by means of which the terahertz radiation IV with the terahertz frequency f THz is generated by means of a nonlinear effect. The non-linear effect can be in particular difference frequency generation.
Dabei entspricht die Linienbreite γ der Terahertzstrahlung IV im Wesentlichen der Breite γ der beiden im Pulsformer gefilterten Frequenzen II. Durch die Veränderung der Frequenz einer oder beider Spektrallinien kann die Differentfrequenz fTHz und damit die Frequenz der Terahertzstrahlung IV in einem sehr weiten Bereich verändert werden. Die Minimalfrequenz der erfmdungsgemäßen Terahertzstrahlungsquelle ist dabei in Näherung durch die Breite γ gegeben. Die Maximalfrequenz der erfindungsgemäßen Terahertzstrahlungsquelle ergibt sich größenordnungsmäßig aus der Breite des ursprünglichen Laserpulses I im Frequenzraum.The line width γ of the terahertz radiation IV essentially corresponds to the width γ of the two frequencies II filtered in the pulse shaper. By changing the frequency of one or both spectral lines, the different frequency f THz and thus the frequency of the terahertz radiation IV can be varied within a very wide range. The minimum frequency of the terahertz radiation source according to the invention is given in approximation by the width γ. The maximum frequency of the terahertz radiation source according to the invention results on the order of magnitude from the width of the original laser pulse I in the frequency domain.
Ferner betrifft die vorliegende Erfindung ein Bildgebungs- und/oder Spektroskopie-System, welches eine erfindungsgemäße Terahertzstrahlungsquelle und einen Terahertzstrahlungssensor, welcher als Detektor dient, umfasst. Dabei können die erfindungsgemäße Terahertzstrahlungsquelle und der Terahertzstrahlungssensor bezüglich des zu untersuchenden Objektes sowohl derart angeordnet sein, dass der Terahertzstrahlungssensor die nach dem Durchstrahlen des Objektes verbleibende Strahlung detektiert als auch dass der Terahertzstrahlungssensor die von dem Objekt reflektierte und/oder gestreute Strahlung detektiert. Folglich können die Terahertzstrahlungsquelle, der Terahertzstrahlungssensor und das Objekt sowohl entlang einer Achse angeordnet sein, wobei das Objekt zwischen der Terahertzstrahlungsquelle und dem Terahertzstrahlungssensor angeordnet ist, als auch nicht entlang einer Achse zueinander angeordnet sein. Das erfindungsgemäße System ermöglicht vorteilhafterweise eine Echtzeit-Spektroskopie im Terahertz-Bereich sowie eine bildgebende Detektierung im Terahertz-Bereich.Furthermore, the present invention relates to an imaging and / or spectroscopy system, which comprises a terahertz radiation source according to the invention and a terahertz radiation sensor, which serves as a detector. In this case, the terahertz radiation source according to the invention and the terahertz radiation sensor with regard to the object to be examined can both be arranged such that the terahertz radiation sensor detects the radiation remaining after passing through the object as well as the terahertz radiation sensor detects the radiation reflected and / or scattered by the object. Thus, the terahertz radiation source, the terahertz radiation sensor, and the object may both be arranged along an axis, the object being located between the terahertz radiation source and the terahertz radiation sensor, as well as not being arranged along an axis. The system according to the invention advantageously enables real-time spectroscopy in the terahertz range as well as imaging detection in the terahertz range.
Im Rahmen einer Ausführungsform des erfindungsgemäßen Bildgebungs- und/oder Spektroskopie- System handelt es sich um ein multispektrales Bildgebungs- und/oder Spektroskopie-System, welches neben dem Terahertzstrahlungssensor weitere Strahlungssensoren, insbesondere Sensoren für Strahlung des sichtbaren, nahinfraroten, und/oder infraroten Bereichs, umfasst.One embodiment of the imaging and / or spectroscopy system according to the invention is a multispectral imaging and / or spectroscopy system which, in addition to the terahertz radiation sensor, has further radiation sensors, in particular sensors for radiation of the visible, near-infrared, and / or infrared range , includes.
Darüber hinaus betrifft die vorliegende Erfindung ein Verfahren zur Detektion und/oder Untersuchung von Lebewesen, insbesondere Menschen und Tieren, Gegenständen und Materialien, mit einem erfindungsgemäßen System. Insbesondere kann dieses Verfahren auf Frequenzbereichsspektroskopie basieren. Vorzugsweise strahlt die erfindungsgemäße Terahertzstrahlungsquelle in dem erfindungsgemäßen Verfahren ein schmales Terahertzband,
beispielsweise mit einer Breite von > 1 Gigahertz bis < 1 Terahertz, insbesondere von > 20 Gigahertz bis < 200 Gigahertz, aus, welches innerhalb eines breiten Frequenzbereichs, beispielsweise in einem Bereich von > 0,3 Terahertz bis < 20 Terahertz, beispielsweise von > 0,3 Terahertz oder von > 0,5 Terahertz oder von > 1 Terahertz bis < 3 Terahertz oder bis < 5 Terahertz oder bis < 10 Terahertz, verändert wird, wobei die transmittierte, reflektierte und/oder gestreute Strahlung durch den, insbesondere breitbandigen, Terahertzstrahlungssensor detektiert, insbesondere gemessen wird. Dabei wird unter einem breitbandigen Terahertzstrahlungssensor beispielsweise ein Terahertzstrahlungssensor verstanden, dessen Detektierungsintervall > 0,3 Terahertz bis < 20 Terahertz, insbesondere > 0,3 Terahertz oder > 0,5 Terahertz oder > 1 Terahertz oder > 1,5 Terahertz bis < 2,5 Terahertz oder < 3 Terahertz oder < 5 Terahertz oder < 10 Terahertz ist. Das Messergebnis des Terahertzstrahlungssensors kann im Rahmen dieses erfindungsgemäßen Verfahrens durch ein Ausgabegerät, beispielsweise ein Display, einen Bildschirm oder einen Drucker, ausgegeben werden.Moreover, the present invention relates to a method for the detection and / or examination of living beings, in particular humans and animals, objects and materials, with a system according to the invention. In particular, this method can be based on frequency domain spectroscopy. Preferably, the terahertz radiation source according to the invention radiates a narrow terahertz band in the method according to the invention, for example, with a width of> 1 gigahertz to <1 terahertz, in particular from> 20 gigahertz to <200 gigahertz, which is within a broad frequency range, for example in a range of> 0.3 terahertz to <20 terahertz, for example> 0 , 3 terahertz or> 0.5 terahertz, or> 1 terahertz to <3 terahertz or <5 terahertz or <10 terahertz, with the transmitted, reflected and / or scattered radiation through the, in particular broadband, terahertz radiation sensor detected, in particular, is measured. A terahertz radiation sensor is understood to mean, for example, a terahertz radiation sensor whose detection interval is> 0.3 terahertz to <20 terahertz, in particular> 0.3 terahertz or> 0.5 terahertz or> 1 terahertz or> 1.5 terahertz to <2.5 Terahertz or <3 terahertz or <5 terahertz or <10 terahertz. The measurement result of the terahertz radiation sensor can be output in the context of this method according to the invention by an output device, for example a display, a screen or a printer.
Weiterhin betrifft die vorliegende Erfindung die Verwendung einer erfindungsgemäßenFurthermore, the present invention relates to the use of an inventive
Terahertzstrahlungsquelle, eines erfindungsgemäßen Systems und/oder eines erfindungsgemäßen Verfahrens im Überwachungs/Sicherheitstechnik-, Transport-, Produktions-, Verpackungs-, Life- Science- und/oder Medizinbereich. Insbesondere betrifft die vorliegende Erfindung die Verwendung einer erfindungsgemäßen Terahertzstrahlungsquelle, eines erfindungsgemäßen Systems und/oder eines erfindungsgemäßen Verfahrens zur Detektion und/oder Untersuchung von Lebewesen, insbesondere Menschen und Tieren, Gegenständen und Materialien, insbesondere Sprengstoffen, beispielsweise bei Sicherheitskontrollen an Grenzen, in Transitgebäuden, wie Flughäfen und Bahnhöfen, in Transportmitteln, wie Bahnen, Bussen, Flugzeugen und/oder Schiffen, und/oder bei Großveranstaltungen, zur Einbruchssicherung von Gebäuden, Räumen und Fortbewegungsmitteln, zu medizinischen Zwecken und/oder zur zerstörungsfreien Überprüfung eines Werkstücks („non- destructive testing"), insbesondere von Werkstücken aus Kunststoff. Beispielsweise können die erfindungsgemäße Terahertzstrahlungsquelle, das erfindungsgemäße System und/oder das erfindungsgemäße Verfahren in einer multispektralen Kamera zur Zugangskontrolle von sensiblen Infrastrukturen und Grenzen, zur zerstörungsfreien Werkstoffprüfung, zur Überwachung von Verpackungsmaschinen oder zur Bestimmung der chemischen Zusammensetzung von biologischemTerahertz radiation source, a system according to the invention and / or a method according to the invention in surveillance / security technology, transportation, production, packaging, life science and / or medical field. In particular, the present invention relates to the use of a terahertz radiation source according to the invention, a system according to the invention and / or a method according to the invention for the detection and / or examination of living beings, in particular humans and animals, objects and materials, in particular explosives, for example at security checks at borders, in transit buildings, such as airports and railway stations, in means of transport, such as trains, buses, aircraft and / or ships, and / or at major events, for burglar-proofing of buildings, premises and means of transportation, for medical purposes and / or non-destructive testing of a workpiece ("non-destructive For example, the terahertz radiation source according to the invention, the system according to the invention and / or the method according to the invention can be used in a multispectral camera for access control of sensitive sensors n Infrastructures and limitations, for non-destructive testing of materials, for monitoring packaging machinery or for determining the chemical composition of biological
Gewebe eingesetzt werden.
Tissue be used.
Claims
1. Terahertzstrahlungsquelle, insbesondere zum Erzeugen einer schmalbandigen, innerhalb eines breiten Frequenzbereichs einstellbaren Terahertzstrahlung, umfassend einen gepulsten Femtosekunden-Faserlaser (1), einen Pulsformer (2), einen optischen Verstärker (3), und - einen nichtlinearen Kristall (4), wobei der Laser (1), Pulsformer (2), optische Verstärker (3) und nichtlineare Kristall (4) derart ausgebildet und/oder angeordnet sind, dass ein vom Laser (1) erzeugter Laserpuls (I, II, III, IV) erst den Pulsformer (2), dann den optischen Verstärker (3) und dann den nichtlinearen Kristall (4) durchläuft .1. Terahertz radiation source, in particular for generating a narrow-band terahertz radiation that can be adjusted within a wide frequency range, comprising a pulsed femtosecond fiber laser (1), a pulse shaper (2), an optical amplifier (3), and - a non-linear crystal (4), where the laser (1), pulse shaper (2), optical amplifier (3) and non-linear crystal (4) are designed and / or arranged in such a way that a laser pulse (I, II, III, IV) generated by the laser (1) only Pulse shaper (2), then the optical amplifier (3) and then the nonlinear crystal (4).
2. Terahertzstrahlungsquelle nach Anspruch 1, dadurch gekennzeichnet, dass der optische Verstärker (3) ein Faserverstärker ist.2. Terahertz radiation source according to claim 1, characterized in that the optical amplifier (3) is a fiber amplifier.
3. Terahertzstrahlungsquelle nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass der Laser (1) Laserpulse mit einer Dauer von > 50 fs bis < 500 fs erzeugt.3. Terahertz radiation source according to claim 1 or 2, characterized in that the laser (1) generates laser pulses with a duration of > 50 fs to < 500 fs.
4. Terahertzstrahlungsquelle nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, dass die Zentralwellenlänge des Lasers (1) in einem Bereich von > 1500 nm bis < 1600 nm liegt.4. Terahertz radiation source according to one of claims 1 to 3, characterized in that the central wavelength of the laser (1) is in a range from >1500 nm to <1600 nm.
5. Terahertzstrahlungsquelle nach einem der Ansprüche 1 bis 4, dadurch gekennzeichnet, dass der5. Terahertz radiation source according to one of claims 1 to 4, characterized in that the
Pulsformer (2) ein Gitter-basierter Pulsformer, ein Prismen-basierter Pulsformer oder ein Mach- Zehnder-Interferometer mit integrierten Fabry-Perot-Filtern ist.Pulse shaper (2) is a grid-based pulse shaper, a prism-based pulse shaper or a Mach-Zehnder interferometer with integrated Fabry-Perot filters.
6. Terahertzstrahlungsquelle nach einem der Ansprüche 1 bis 5, dadurch gekennzeichnet, dass das Mach-Zehnder-Interferometer: einen ersten Strahlenteiler zum Teilen des Laserpulses in einen ersten und einen zweiten Laserpuls,
einen ersten Fabry-Perot-Filter zum Herausfiltern einer Frequenz aus dem ersten Laserpuls und einen zweiten Fabry-Perot-Filter zum Herausfiltern einer anderen Frequenz aus dem zweiten Laserpuls, und einen zweiten Strahlenteiler zum Überlagern des ersten und zweiten Laserpulses, umfasst.6. Terahertz radiation source according to one of claims 1 to 5, characterized in that the Mach-Zehnder interferometer: a first beam splitter for dividing the laser pulse into a first and a second laser pulse, a first Fabry-Perot filter for filtering out a frequency from the first laser pulse and a second Fabry-Perot filter for filtering out another frequency from the second laser pulse, and a second beam splitter for superimposing the first and second laser pulses.
7. Terahertzstrahlungsquelle nach einem der Ansprüche 1 bis 6, dadurch gekennzeichnet, dass der erste und/oder zweite Strahlenteiler ein Y-Faserkoppler ist.7. Terahertz radiation source according to one of claims 1 to 6, characterized in that the first and / or second beam splitter is a Y-fiber coupler.
8. Terahertzstrahlungsquelle nach einem der Ansprüche 1 bis 7, dadurch gekennzeichnet, dass die Fabry-Perot-Filter mikroelektromechanische Fabry-Perot-Filter sind.8. Terahertz radiation source according to one of claims 1 to 7, characterized in that the Fabry-Perot filters are microelectromechanical Fabry-Perot filters.
9. Terahertzstrahlungsquelle nach einem der Ansprüche 1 bis 8, dadurch gekennzeichnet, dass die Terahertzstrahlungsquelle Terahertzstrahlung mit einer Breite von > 1 Gigahertz bis < 1 Terahertz erzeugt, die innerhalb eines Frequenzbereichs von > 0,3 Terahertz bis < 20 Terahertz einstellbar ist.9. Terahertz radiation source according to one of claims 1 to 8, characterized in that the terahertz radiation source generates terahertz radiation with a width of > 1 gigahertz to < 1 terahertz, which is adjustable within a frequency range of > 0.3 terahertz to < 20 terahertz.
10. Verfahren zum Erzeugen von Terahertzstrahlung, insbesondere zum Erzeugen einer schmalbandigen, innerhalb eines breiten Frequenzbereichs einstellbaren Terahertzstrahlung, mit einer Terahertzstrahlungsquelle nach einem der Ansprüche 1 bis 9, umfassend die Verfahrensschritte: 1. Erzeugen eines Laserpulses (I) durch den Laser (1),10. A method for generating terahertz radiation, in particular for generating a narrow-band terahertz radiation that can be adjusted within a wide frequency range, with a terahertz radiation source according to one of claims 1 to 9, comprising the method steps: 1. Generating a laser pulse (I) by the laser (1) ,
2. Umformen des Laserpulses (I) in einen Laserimpuls (II), dessen Spektrum mindestens zwei Maxima bei unterschiedlichen2. Converting the laser pulse (I) into a laser pulse (II) whose spectrum has at least two maxima at different
Frequenzen aufweist, und/oder in mindestens zwei Laserpulse (II) unterschiedlicher Frequenz, durch den Pulsformer (2);Frequencies, and / or in at least two laser pulses (II) of different frequencies, through the pulse shaper (2);
3. Verstärken des Laserpulses (II), dessen Spektrum mindestens zwei Maxima bei unterschiedlichen3. Amplifying the laser pulse (II), the spectrum of which has at least two maxima at different
Frequenzen aufweist, zu einem verstärkten Laserpuls (III), und/oder der Laserpulse (II) unterschiedlicher Frequenz zu verstärkten Laserpulsen (III), durch den optischen Verstärker (3), undFrequencies, to an amplified laser pulse (III), and / or the laser pulses (II) of different frequencies to amplified laser pulses (III), by the optical amplifier (3), and
4. Erzeugen von Terahertzstrahlung (IV) durch Differenzfrequenz-Generierung der Differenzfrequenz (fTHz) zwischen den Maxima bei unterschiedlichen Frequenzen des verstärkten Laserimpulses (III) und/oder durch Differenzfrequenz-Generierung der Differenzfrequenz (frHz) zwischen den unterschiedlichen Frequenzen der verstärkten Laserimpulse (III), durch den nichtlinearen Kristall (4),
umfasst.4. Generating terahertz radiation (IV) by difference frequency generation of the difference frequency (f THz ) between the maxima at different frequencies of the amplified laser pulse (III) and/or by difference frequency generation of the difference frequency (fr Hz ) between the different frequencies of the amplified laser pulses (III), through the nonlinear crystal (4), includes.
11. Verfahren nach Anspruch 10, dadurch gekennzeichnet, dass die Frequenz der Terahertzstrahlung (IV) durch Durchstimmen des Pulsformers (2), insbesondere durch Durchstimmen der Differenzfrequenz (frHz), eingestellt wird.11. The method according to claim 10, characterized in that the frequency of the terahertz radiation (IV) is set by tuning the pulse shaper (2), in particular by tuning the difference frequency (fr Hz ).
12. Bildgebungs- und/oder Spektroskopie-System, umfassend eine Terahertzstrahlungsquelle nach einem der Ansprüche 1 bis 9 und einen Terahertzstrahlungssensor.12. Imaging and/or spectroscopy system comprising a terahertz radiation source according to one of claims 1 to 9 and a terahertz radiation sensor.
13. Verfahren zur Detektion und/oder Untersuchung von Lebewesen, insbesondere Menschen und Tieren, Gegenständen und Materialien, mit einem System nach Anspruch 12, in dem die Terahertzstrahlungsquelle ein schmales Terahertzband ausstrahlt, welches innerhalb eines breiten Frequenzbereichs verändert wird, wobei die transmittierte, reflektierte und/oder gestreute Strahlung durch den Terahertzstrahlungssensor detektiert wird.13. A method for detecting and/or examining living beings, in particular people and animals, objects and materials, with a system according to claim 12, in which the terahertz radiation source emits a narrow terahertz band, which is changed within a wide frequency range, the transmitted being reflected and/or scattered radiation is detected by the terahertz radiation sensor.
14. Verwendung einer Terahertzquelle nach einem der Ansprüche 1 bis 9 und/oder eines Systems nach Anspruch 12 im Überwachungs/Sicherheitstechnik-, Transport-, Produktions-, Verpackungs-, Life-Science- und/oder Medizinbereich, insbesondere zur Detektion und/oder Untersuchung von Lebewesen, Gegenständen und Materialien, beispielsweise bei Sicherheitskontrollen an Grenzen, in Transitgebäuden, in Transportmitteln, und/oder bei Großveranstaltungen, zur Einbruchssicherung von Gebäuden, Räumen und Fortbewegungsmitteln, zu medizinischen Zwecken und/oder zur zerstörungsfreien Überprüfung eines Werkstücks.
14. Use of a terahertz source according to one of claims 1 to 9 and/or a system according to claim 12 in the surveillance/security technology, transport, production, packaging, life science and/or medical sectors, in particular for detection and/or Examination of living beings, objects and materials, for example during security checks at borders, in transit buildings, in means of transport, and/or at major events, to protect against burglary of buildings, rooms and means of transport, for medical purposes and/or for the non-destructive inspection of a workpiece.
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| PCT/EP2009/057072 WO2010015443A1 (en) | 2008-08-07 | 2009-06-09 | Terahertz radiation source and method for producing terahertz radiation |
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| CN102664337B (en) * | 2012-05-09 | 2013-09-11 | 南开大学 | Terahertz wave source based on ytterbium germanium co-doping micro-structural optical fiber narrow-line-width dual-wavelength laser |
| JP2014141296A (en) * | 2012-12-27 | 2014-08-07 | Dainippon Printing Co Ltd | Storage body, laminate, and authenticity determination method for storage body and laminate |
| RU2539678C2 (en) * | 2013-04-16 | 2015-01-20 | Федеральное государственное бюджетное учреждение науки Институт общей физики им. А.М. Прохорова Российской академии наук | Method of generating electromagnetic radiation in terahertz range and apparatus for generating electromagnetic radiation in terahertz range |
| KR102132511B1 (en) * | 2013-12-04 | 2020-07-09 | 마이크로테크 인스트러먼츠, 인크. | Systems and methods for high-contrast, near-real-time acquisition of terahertz images |
| CN103633545A (en) * | 2013-12-07 | 2014-03-12 | 山东海富光子科技股份有限公司 | Difference-frequency tunable single-frequency terahertz source with external cavity strengthened |
| CN104013387B (en) * | 2014-06-12 | 2016-01-27 | 清华大学 | A kind of Terahertz fast tomographic imaging system and method |
| RU2690064C2 (en) * | 2017-05-15 | 2019-05-30 | Федеральное государственное казенное военное образовательное учреждение высшего образования "Военный учебно-научный центр Военно-Морского Флота "Военно-морская академия им. Адмирала Флота Советского Союза Н.Г. Кузнецова" | Method for generation of electromagnetic radiation in wide range of radio communication |
| RU2690066C2 (en) * | 2017-05-15 | 2019-05-30 | Федеральное государственное казенное военное образовательное учреждение высшего образования "Военный учебно-научный центр Военно-Морского Флота "Военно-морская академия им. Адмирала Флота Советского Союза Н.Г. Кузнецова" | Broadband antenna |
| RU2687985C2 (en) * | 2017-06-05 | 2019-05-17 | Федеральное государственное казенное военное образовательное учреждение высшего образования "Военный учебно-научный центр Военно-Морского Флота "Военно-морская академия имени Адмирала флота Советского Союза Н.Г. Кузнецова" | Broadband radio transmitter |
| JP7522561B2 (en) * | 2019-03-14 | 2024-07-25 | キヤノン株式会社 | Mobile |
| US20200296266A1 (en) * | 2019-03-14 | 2020-09-17 | Canon Kabushiki Kaisha | Movable body |
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2008
- 2008-08-07 DE DE102008041107A patent/DE102008041107A1/en not_active Withdrawn
-
2009
- 2009-06-09 CN CN2009801305038A patent/CN102119359A/en active Pending
- 2009-06-09 WO PCT/EP2009/057072 patent/WO2010015443A1/en active Application Filing
- 2009-06-09 RU RU2011108214/28A patent/RU2011108214A/en not_active Application Discontinuation
- 2009-06-09 JP JP2011521495A patent/JP2011530092A/en active Pending
- 2009-06-09 US US13/055,659 patent/US20110121209A1/en not_active Abandoned
- 2009-06-09 EP EP09779681A patent/EP2324389A1/en not_active Withdrawn
Non-Patent Citations (1)
| Title |
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| See references of WO2010015443A1 * |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2010015443A1 (en) | 2010-02-11 |
| US20110121209A1 (en) | 2011-05-26 |
| JP2011530092A (en) | 2011-12-15 |
| CN102119359A (en) | 2011-07-06 |
| DE102008041107A1 (en) | 2010-02-11 |
| RU2011108214A (en) | 2012-09-20 |
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