A method for generating a single-pulse time-sequence interval adjustable multi-pulse terahertz beam

Abstract

The application provides a method for generating a multi-pulse terahertz beam with adjustable time interval of single pulse, which comprises the following steps: generating a pulse signal from a same terahertz wave source, then generating two or more pulse signals with consistent performance parameters through beam distribution, generating time interval through different time delay paths, and achieving the detection purpose by hitting the same detection area of the same research object. The method is based on the high-speed and high-precision modulation technology of the terahertz pulse of the pulse beam quasi-optical slow wave generator, and can realize the adjustment of the time interval of the pulse beam.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of chemistry, material science and environmental chemistry, and particularly relates to a method for generating a multi-pulse terahertz beam with adjustable time interval. BACKGROUND

[0002] The method for generating a multi-pulse terahertz beam with adjustable time interval can be applied to an electron spin resonance spectrometer (ESR, Electron Spin Resonance), greatly improving the time and space resolution and detection sensitivity of the device, and being used for measuring the electron spin resonance phenomenon of unpaired electrons in solid, liquid, gas and other substances, and for researching transition metal ions and their complexes, radiation metrology, free radical detection, electron transfer reaction, oxygen free radicals, antioxidant and free radical scavenger, etc.; in the field of environmental chemistry, the basic theory of free radical reactions occurring in the degradation of various pollutants or other chemical processes is researched.

[0003] The electron spin resonance spectrometer (ERS, Electron Spin Resonance) is a very valuable analytical method in the study of the microstructure of substances, and has high practical value, but the device needs to use terahertz waves to realize the function. Since the frequency of terahertz waves is very high, it is difficult to obtain terahertz waves with high peak power, high beam quality and good pulse stability. In addition, in order to realize the function of the device, the terahertz waves need to be edited into a pulse sequence, and the pulse interval is required to be very short, typically on the order of hundreds of nanoseconds.

[0004] Solid-state terahertz sources and vacuum electron devices can generate pulsed terahertz waves and can be used as the terahertz source of the device. The solid-state terahertz source generally has small power, but can realize high peak power through power synthesis and other methods; the vacuum electron device has high peak power and can be directly used as the terahertz source of the device.

[0005] The electron spin resonance spectrometer requires that the time interval of two or more continuous pulses generated by the terahertz source is on the order of hundreds of nanoseconds. Due to the structural characteristics of the solid-state source or the vacuum electron device, the interval between the generated time pulses is large and cannot meet the requirements. At present, there is a method of using two or more terahertz wave sources to work according to a certain time interval to generate a terahertz beam, so as to achieve a pulse interval on the order of hundreds of nanoseconds. By controlling the time interval between the beams generated by the wave sources, a double-pulse terahertz beam with adjustable time interval can be realized. However, the control of the pulse time interval, pulse waveform and power consistency is difficult, and the device is complex. SUMMARY

[0006] To solve the above technical problems, the method for generating multi-pulse terahertz beams with adjustable time interval of single pulse according to the application can obtain pulse sequence with interval of 100 nanoseconds conveniently. A terahertz wave source is used to emit a pulse beam, the emitted beam is divided into two or more beams by a device, so that the beams have the same characteristics; then the delay system is used to delay the time when the specific beam reaches the research object, so that the time interval between the two beams is very small. Moreover, the delay time of the delay system can be designed to be adjustable, so that the time interval when the beam reaches the research object can be adjusted.

[0007] In the electron spin resonance spectrometer, the high-power terahertz wave is edited into a pulse sequence with variable pulse interval time, and the high-speed modulation method of the terahertz wave time sequence pulse is the basis and key for the application of the electron spin resonance spectrometer. The application utilizes the spatial mode transformation and synthesis technology of the terahertz wave to generate two or more terahertz pulse beams with controllable and adjustable time interval. The application mainly includes the following technical methods: the spatial beam distribution technology of the terahertz wave, which realizes the conversion of a single terahertz beam into two terahertz pulses; the time domain control technology of the terahertz beam, which realizes the time sequence modulation method between the terahertz beams; the spatial synthesis and focusing technology of the terahertz beam, which realizes the spatial positioning problem of the terahertz beam on the research object.

[0008] To achieve the above object, the application adopts the following technical scheme:

[0009] A method for generating a single-pulse time interval adjustable multi-pulse terahertz beam, a terahertz wave source emits a terahertz pulse beam with a frequency range of 0.1 THz-10 THz, which contains multiple short pulses, and is incident into the microwave signal inlet of an electron spin resonance spectrometer system with a larger time interval; the incident beam emitted by the terahertz wave source is transmitted through a space and then hits the beam distributor, the beam distributor divides the incident beam into reflected and transmitted beams, both beams have the same amplitude; the reflected beam is transmitted through a space and then hits the spatial beam combiner, and is reflected and focused by the spatial beam combiner and then directly hits the detection area of the research object; the beam time domain adjuster includes a group of beam reflectors, a beam adjuster, and a beam calibrator; the transmitted beam is transmitted through a space and then hits the beam adjuster of the beam time domain adjuster, is adjusted by the beam adjuster, and then is incident on the first beam reflector at a suitable angle, and is then reflected by each beam reflector; the reflection of the beam between the beam reflectors increases the transmission distance of the beam, and the beam time domain adjuster achieves the purpose of delaying the beam, and the delayed time is in the order of nanoseconds; the delayed beam is incident on the beam calibrator, and the angle of the beam emitted from the beam calibrator can be adjusted by adjusting the angle of the beam calibrator, so that the beam is incident on the spatial beam combiner at a suitable angle; the spatial beam combiner reflects and focuses the delayed transmitted beam, transmits it through a space, and then hits the detection area of the research object, at the same position as the reflected beam; after the above steps, two pulse groups with the same characteristics and a time interval in the order of nanoseconds are formed in the detection area of the research object, and the detection goal of the electron spin resonance spectrometer is achieved.

[0010] Further, the terahertz wave source is a synthetic solid-state source or a high-power vacuum electron device with sufficient power.

[0011] Further, the terahertz wave source is a high-power gyrotron.

[0012] Further, one of the beam reflectors is replaced by a beam distributor.

[0013] Further, the beam distributor is a terahertz pulse beam quasi-optical slow wave distributor designed based on the transmission and reflection principles of electromagnetic waves, made of a low-loss wave-transparent medium with a specific shape, and after the beam is incident, part of the energy is transmitted to form a transmitted wave, and part of the energy is reflected to form a reflected wave. The amplitude ratio of the transmitted wave and the reflected wave is determined by the material, shape, and position of the beam distributor.

[0014] Further, the two beams divided by the beam distributor are incident into the beam time domain adjuster. The function of the beam time domain adjuster is to lengthen the transmission path of the beam and delay the time of the beam reaching the research object. The main part of the beam time domain adjuster is the beam reflector, which is composed of multi-faceted beam reflector. The beam transmitted into the beam time domain adjuster is reflected by the beam reflector and then exits to the spatial beam combiner at a certain angle. The distance between the beam reflectors is adjustable, so as to adjust the transmission time of the beam in the beam time domain adjuster. The beam time domain adjuster can also contain a beam adjuster and a beam calibrator. The function of the beam adjuster is to receive the beam transmitted from the beam distributor and adjust the incident angle of the beam incident into the beam reflector of the beam time domain adjuster. The function of the beam calibrator is to adjust the angle of the beam exiting from the beam time domain adjuster, so that the beam can correctly hit the spatial beam combiner.

[0015] Further, the spatial beam combiner is a curved beam reflector which can focus the beam. The spatial beam combiner is designed in a curved form, so that it has a focal point. The beams hitting different positions on the spatial beam combiner all pass through the focal point after reflection. The research object is placed at a specific position, so that the region to be detected is located at the focal point of the spatial beam combiner, and the beams with different time delays all hit the region to be detected.

[0016] Beneficial effects:

[0017] The present application uses a terahertz wave source to emit a pulse beam, divides the emitted beam into two or more beams through the device, so that the beams have the same characteristics. Then, the delay system is used to delay the time of a specific beam reaching the research object, so that the time interval between the two beams is very small. Moreover, the delay time of the delay system can be designed to be adjustable, so as to realize the adjustment of the time interval of the beams reaching the research object. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 Figure 1 is a schematic diagram of embodiment 1 of the method for generating time interval adjustable multi-pulse terahertz beam by single pulse according to the present application.

[0019] Figure 2 Figure 2 is a schematic diagram of embodiment 2 of the method for generating time interval adjustable multi-pulse terahertz beam by single pulse according to the present application.

[0020] In the figure, 1 is a terahertz wave source, 2 is an incident beam, 3 is a reflected beam, 4 is a transmitted beam, 41 is a transmitted beam, 5 is a beam distributor, 6 is a beam time domain adjuster, 61 is a beam reflector, 62 is a beam adjuster, 63 is a beam calibrator, 7 is a spatial beam combiner, and 8 is a research object. DETAILED DESCRIPTION

[0021] In order to make the objects, technical solutions and advantages of the present application clearer, further detailed description will be made to the present application in combination with the accompanying drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and not used to limit the present application. In addition, the technical features involved in each embodiment of the present application described below can be combined with each other as long as they do not conflict with each other.

[0022] As shown in Figure 1 Embodiment 1 of the method for generating single-pulse time interval adjustable multi-pulse terahertz wave beam of the present application is a typical embodiment. The terahertz wave source 1 emits a terahertz pulse wave beam with a frequency range of 0.1 THz-10 THz, which contains multiple short pulses, and the beam is incident into the microwave signal inlet of the electron spin resonance spectrometer system with a larger time interval (such as 1 ms). The terahertz wave source 1 can be a synthetic solid-state source or a high-power vacuum electron device with sufficient power, and a high-power gyrotron is used in this embodiment, which has the characteristics of high power amplitude and simple structure. The beam emitted by the terahertz wave source 1 (i.e. incident beam 2) hits the beam distributor 5 after a space transmission, and the beam distributor 5 divides the incident beam 2 into reflected beam 3 and transmitted beam 4, both of which have the same amplitude. The reflected beam 3 hits the spatial beam synthesizer 7 after a space transmission, and is reflected and focused by the spatial beam synthesizer 7 and then directly hits the detection area of the research object. The beam time domain adjuster 6 contains six beam reflectors 61, one beam adjuster 62 and one beam calibrator 63. The transmitted beam 4 hits the beam adjuster 62 of the beam time domain adjuster 6 after a space transmission, and is adjusted by the beam adjuster 62 and then incident into the first beam reflector 61 at a suitable angle, and then is reflected by each beam reflector 61. The reflection of the beam between the beam reflectors 61 increases the transmission distance of the beam, and the beam time domain adjuster 6 achieves the purpose of delaying the beam, and the delayed time is in the order of nanoseconds. The delayed beam is incident into the beam calibrator 63, and the angle of the beam emitted from the beam calibrator 63 can be adjusted by adjusting the angle of the beam calibrator 63, so that the beam is incident into the spatial beam synthesizer 7 at a suitable angle. The spatial beam synthesizer 7 reflects and focuses the delayed transmitted beam 4, and hits the detection area of the research object 8 (at the same position as the reflected beam 3) after a space transmission.

[0023] After the above steps, two pulse groups with the same characteristics and a time interval in the order of nanoseconds are formed in the detection area of the research object 8, and the detection goal of the electron spin resonance spectrometer is achieved.

[0024] Figure 2The embodiment 2 is given based on the embodiment 1, which is extended to generate three beams of pulses. The front part of the structure of the embodiment is basically the same as the embodiment 1, only one of the beam reflectors 61 is replaced by the beam distributor 5, so as to split a set of transmitted beams 41. The transmitted beams 41 are reflected by the beam adjuster 62 to adjust the incident angle, the beam reflector 61 to increase the time delay of the reflected beams, and the beam collimator 63 to adjust the exit angle, and then hit the spatial beam combiner 7; the transmitted beams 41 are reflected and focused by the spatial beam combiner 7, and finally hit the to-be-detected area of the research object.

[0025] The embodiment 2 generates three beams of pulse waves with a certain time interval, so as to realize more detection functions of the electron spin resonance spectrometer.

[0026] Those skilled in the art can easily understand that the above description is only the preferred embodiment of the present application, and is not used to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for generating a multi-pulse terahertz beam with adjustable timing intervals from a single pulse, characterized in that, The application relates to a method for obtaining a pulse sequence with a time interval of the order of nanoseconds; a terahertz wave source emits a terahertz pulse beam with a frequency range of 0.1 THz-10 THz, the terahertz pulse beam contains multiple short pulses, and the terahertz pulse beam is incident into a microwave signal inlet of an electron spin resonance spectrometer system in a larger time interval; the incident beam emitted by the terahertz wave source is transmitted through a space and then hits a beam distributor; the beam distributor divides the incident beam into a reflected beam and a transmitted beam; the reflected beam is transmitted through a space and then hits a space beam synthesizer; the reflected beam is reflected and focused by the space beam synthesizer and then directly hits a detection area of a research object; the beam time domain adjuster contains a group of beam reflectors, a beam adjuster and a beam calibrator; the transmitted beam is transmitted through a space and then hits the beam adjuster of the beam time domain adjuster; the transmitted beam is adjusted by the beam adjuster and then hits the first beam reflector at a proper angle; the transmitted beam is reflected by the beam reflectors; the reflection of the beam between the beam reflectors increases the transmission distance of the beam and achieves the purpose of delaying the beam; the delayed time of the beam is of the order of nanoseconds; the delayed beam hits the beam calibrator; the angle of the beam exiting from the beam calibrator can be adjusted by adjusting the angle of the beam calibrator, so that the beam can hit the space beam synthesizer at a proper angle; the space beam synthesizer reflects and focuses the delayed transmitted beam; the delayed transmitted beam is transmitted through a space and then hits the detection area of the research object, and the delayed transmitted beam hits the same position as the reflected beam; through the above steps, two pulse groups with the same characteristics and a time interval of the order of nanoseconds are formed in the detection area of the research object, and the detection purpose of the electron spin resonance spectrometer is achieved.

2. The method of claim 1, wherein the time interval of the multi-pulse THz beam is adjustable. The terahertz wave source is a synthetic solid-state source or a high-power vacuum electron device with sufficient power.

3. The method of claim 1, wherein the time interval of the multi-pulse THz beam is adjustable. The terahertz wave source is a high-power gyrotron.

4. The method of claim 1-3, wherein the time interval of the multi-pulse THz beam is adjustable. One of the beam reflectors is replaced by a beam distributor.

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