JP4132193B2 - Superconducting terahertz electromagnetic wave generation module - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to superconducting THz onset Namamo Joules.
[0002]
[Prior art]
At present, gas-excited far-infrared lasers, femtosecond pulse laser excitation types, and the like are mainly used as oscillators in the terahertz band.
[0003]
[Problems to be solved by the invention]
However, in addition to the drawbacks of these devices being large, difficult to operate, and poor controllability, gas-pumped far-infrared lasers have a discrete output frequency and provide a high output signal with an arbitrary frequency. It is impossible to get.
[0004]
Further, the output of the femtosecond pulse laser excitation type oscillator is a pulse signal, which is unsuitable for applications requiring a continuous wave signal with high spectral purity.
[0005]
Furthermore, in order to realize precise measurement, it is necessary to monitor output information such as the frequency and power of the oscillator and at the same time perform control based on the monitor information.
[0006]
For this purpose, there is a heterodyne mixing technique that is often used in the microwave band. However, because the conversion efficiency decreases rapidly with increasing frequency, it is difficult to apply to the terahertz band, and the broadband It is impossible to measure continuously.
[0007]
Optical techniques such as diffraction and interference are also used, but there are problems such as complicated operation and increase of diffraction loss due to long wavelength.
[0008]
The present invention eliminates the above-mentioned problems, enables the generation of coherent continuous electromagnetic waves with variable frequency by controlling the injected quasiparticles and AC Josephson current, and enables continuous measurement of output information associated with the generation of the continuous electromagnetic waves. and to provide a superconducting THz onset Namamo joules.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides
[ 1 ] In a superconducting terahertz electromagnetic wave generating module, a high-temperature superconducting Josephson junction device (1) comprising a bicrystal substrate (10) in which two single crystals having different crystal orientations are synthesized by diffusion bonding by a high vacuum hot pressing method (1) 11), a high-temperature superconducting thin film (18) formed on the bicrystal substrate (10), and an external junction (3A, 13A) formed on the high-temperature superconducting thin film (18) and plasma resonance. And a part of the amplified signal by exciting a weak high-frequency signal, resonating the signal in the external junction (3A, 13A) and the plasma resonator (3, 13). Is transmitted to the high-temperature superconducting Josephson junction device (1, 11) through the strip wire (20), and the electrical characteristics of the high-temperature superconducting Josephson junction device (1, 11) are measured. And the feedback high temperature superconductor Josephson junction device (1, 11) and the plasma cavity to the (3, 13) as well as monitor the characteristics of the signal, is obtained so as to enable control the signal.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail.
[0011]
FIG. 1 is a configuration diagram of a superconducting terahertz electromagnetic wave generation system showing an embodiment of the present invention, and FIG. 2 is a perspective view showing a module obtained by solidifying the superconducting terahertz electromagnetic wave generation system.
[0012]
In these figures, 10 is a bicrystal substrate, 1 and 11 are bicrystal JJ, 2, 12: 4 are transmission lines, 3 and 13 are single crystal plasma resonators (terahertz-band oscillators), and 3A and 13A are single units. External junction of crystal plasma resonator, 5, 15: 6, 16 are current / voltage lead wires, 7 and 17 are output terminals, 18 is a high-temperature superconducting thin film, 19 is a metal film, 20 is a strip line, 21 is It is a control device.
[0013]
Hereinafter, the main part which comprises the superconducting terahertz electromagnetic wave generation system which shows the Example of this invention is demonstrated.
[0014]
Here, bicrystal JJ (1, 11) will be described. A substrate obtained by synthesizing two single crystals having different crystal orientations (oblique angles) by diffusion bonding using a high vacuum hot press method is called a bicrystal substrate. The connection interface between two single crystals is called a grain boundary and forms a weak bond.
[0015]
Josephson Junction (JJ) is a superconductingly weak coupling part (bridge type: constricted shape, tunneling junction: shape with a thin insulating layer, metal layer, etc.) in materials such as superconducting thin films and bulk. It is an element having non-linear electrical characteristics formed by fabrication. Like a PN junction in a semiconductor region, JJ is the most basic element as a superconducting electronic device. Expected to be used as high-frequency devices such as oscillators and detectors.
[0016]
The bicrystal JJ (1, 11) is a superconducting element, and this superconducting element forms a grain boundary in the thin film by epitaxially growing the high-temperature superconducting thin film 18 on the bicrystal substrate 10 described above. The thin film on the grain boundary is made thinner by etching, so that the superconducting current flows uniformly.
[0017]
In addition, bicrystal JJ (1, 11) is better fabricated and has better reproducibility than other high temperature superconducting JJs and has been demonstrated to operate at very high frequencies at high operating temperatures. Here, it has a function of measuring the oscillated signal.
[0018]
Next, the transmission paths (2, 12) and (4) will be described. Microstrip lines, dielectric transmission lines, and in-air transmission and quasi-optical systems in the terahertz band are also conceivable. In FIG. 2, it is formed as a microstrip line 12 and has a function of transmitting an oscillated signal.
[0019]
Next, the single crystal plasma resonator (3, 13) will be described. The copper oxide high-temperature superconducting single crystal has a strong anisotropy due to its layered structure, and thus a phenomenon called plasma oscillation exists. In addition, since the energy corresponding to the frequency of this plasma oscillation is smaller than the large energy gap of the high-temperature superconductor, an electromagnetic wave having a frequency between the plasma frequency (several tens of gigahertz) and the frequency corresponding to the energy gap (several terahertz). Is characteristic in that it can propagate without being attenuated in a high-temperature superconducting single crystal.
[0020]
A single-crystal plasma resonator (3, 13) is produced by producing a single-crystal material having the characteristics of this plasma oscillation with a certain size (integer multiple of wavelength or size of 1 / integer). The single crystal plasma resonator (3, 13) has a function of amplifying and outputting the excited high frequency signal. That is, it becomes a terahertz band oscillator. The single crystal plasma resonators (3, 13) are formed with external joints 3A, 13A.
[0021]
The bicrystal JJ (1, 11) and the single crystal plasma resonator (3, 13) are supplied with current through the current / voltage lead wires 5, 15: 6, 16 respectively, thereby producing the bicrystal JJ (1, 11). 11) and the single crystal plasma resonator (3, 13) are biased. In addition, a voltage is output through the current / voltage lead wires 5, 15: 6, 16 and by measuring the voltage, the bicrystal JJ (1, 11) and the single crystal plasma resonator (3, 13) are output. ) Is measured by the control device 21, and the system can be controlled based on this output information.
[0022]
In particular, as shown in FIG. 2, after the high-temperature superconducting thin film 18 is epitaxially grown on the bicrystal substrate 10, the designed dimensions (JJ junction width, resonator, transmission line, electrode size, etc.) are etched. By forming an insulating layer (used for forming a capacitance for high-frequency energy coupling or electrical insulation) and a metal layer 19 (current, voltage electrode terminal, etc.), a solidified module can be obtained.
[0023]
A weak high-frequency signal is excited by an external junction (such as a tunneling junction for quasiparticle injection or a Josephson junction using the AC Josephson effect) on a resonator having a certain size, and the signal is resonated in the resonator. A part of the amplified signal is transmitted to the bicrystal JJ (11) through the strip line 20, and by measuring the electrical characteristics of the bicrystal JJ (11), the characteristics of the signal (frequency, output power, frequency and power) When the controller 21 monitors the stability, spectral purity, etc.), the information is simultaneously fed back to the information excitation vibration junction to control the signal.
[0024]
On the other hand, the remaining part of the signal becomes an oscillator by transmitting it to the necessary place through the air or other transmission paths.
[0025]
As described above, according to the present invention, a high-temperature superconducting thin film that is much smaller than a gas-excited far-infrared laser and uses a high-temperature superconducting single crystal and a high-temperature superconducting thin film. It may constitute a conductive THz radiation onset Namamo joules.
[0026]
In addition, a variable frequency coherent continuous electromagnetic wave can be generated by controlling the injected quasiparticles and AC Josephson current.
[0027]
Furthermore, the electromagnetic wave generation circuit can be controlled quickly and accurately by combining with a Josephson detector capable of measuring a spectrum in a wide band up to the terahertz band, which has been impossible to measure continuously.
[0028]
In addition, this invention is not limited to the said Example, A various deformation | transformation is possible based on the meaning of this invention, and these are not excluded from the scope of the present invention.
[0029]
【The invention's effect】
As described above in detail, according to the present invention, the following effects can be obtained.
[0030]
Using bicrystal substrate and the high temperature superconducting thin film made of a high-quality high-temperature superconductor single crystals, a small much more gas pumped far-infrared laser, constitute a highly efficient superconducting terahertz electromagnetic wave onset Namamo Joules be able to.
[0031]
In addition, a variable frequency coherent continuous electromagnetic wave can be generated by controlling the injected quasiparticles and AC Josephson current.
[0032]
By combining with a Josephson detector capable of measuring a spectrum in a wide band up to the terahertz band, which could not be continuously measured until now, the electromagnetic wave generating circuit can be controlled quickly and accurately.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a superconducting terahertz electromagnetic wave generation system showing an embodiment of the present invention.
FIG. 2 is a perspective view showing a module obtained by solidifying a superconducting terahertz electromagnetic wave generation system according to an embodiment of the present invention.
[Explanation of symbols]
1,11 Bicrystal JJ
2,12: 4 Transmission path 3,13 Single crystal plasma resonator (terahertz band oscillator)
3A, 13A External junction 5, 15: 6, 16 Current / voltage lead wire 7, 17 Output terminal 10 Bicrystal substrate 18 High-temperature superconducting thin film 19 Metal layer 20 Strip line 21 Control device

Claims (1)

In the superconducting terahertz electromagnetic wave generation module,
(A) a high-temperature superconducting Josephson junction device (1, 11) comprising a bicrystal substrate (10) obtained by synthesizing two single crystals having different crystal orientations by diffusion bonding using a high vacuum hot press method;
(B) a high-temperature superconducting thin film (18) formed on the bicrystal substrate (10);
(C) an external junction (3A, 13A) formed on the high-temperature superconducting thin film (18) and a plasma resonator (3, 13);
(D) A weak high-frequency signal is excited, the signal is resonated in the external junction (3A, 13A) and the plasma resonator (3, 13), and a part of the amplified signal is stripped by the strip line (20). The high-temperature superconducting Josephson junction device (1, 11) is transmitted, the electrical characteristics of the high-temperature superconducting Josephson junction device (1, 11) are measured, the signal characteristics are monitored, and the high-temperature superconducting Josephson device A superconducting terahertz electromagnetic wave generating module that feeds back to a bonding device (1, 11) and a plasma resonator (3, 13) to control the signal.

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