A multi-band microwave superheterodyne receiver based on solid-state quantum system

Abstract

The application discloses a multi-frequency band microwave superheterodyne receiver based on a solid quantum system, which comprises a diamond (1), a light source (2), a dichroic mirror (3), a photoelectric detector (4), a control and processing system (5), an antenna (6), a reference microwave source (7) and a magnetic field generating and adjusting device. The ground state energy level of a nitrogen vacancy color center in the diamond (1) is regulated by controlling the light source (2) and the magnetic field generating and adjusting device. When a to-be-detected microwave and a reference microwave simultaneously act on the nitrogen vacancy color center of the diamond, frequency mixing is generated. Through the effect, the control and processing system (5) reads in an electric signal from the photoelectric detector (4), and the accurate detection of a to-be-detected microwave frequency and phase is realized. The system is simple and easy to integrate, and can be applied to a microwave quantum radar, so that wide spectrum and large dynamic target echo information can be acquired, and the detection performance is better than that of a traditional radar.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of microwave quantum detection, in particular to a multi-band microwave superheterodyne receiver based on a solid-state quantum system. BACKGROUND

[0002] Microwave is an important information carrier in the fields of communication, radar, metrology, astronomy, etc., and it is always of great significance to detect it with high sensitivity. The demand of social development promotes the development of microwave detection and receiving technology towards wide spectrum, large dynamic range, integration, multi-function, etc. The traditional microwave receiver has been developed for more than a hundred years, and the technology has entered a slow improvement period, gradually failing to meet the increasing demand. The essence of the traditional microwave receiver is to extract the microwave electric field information by inducing the movement of free electrons in the metal to produce regular induced current; however, on the one hand, the random thermal motion of free electrons in the metal introduces random thermal noise in the induced current, limiting the further improvement of detection sensitivity; on the other hand, when detecting wide spectrum microwave signals, the traditional microwave receiver generally needs to use multiple antennas, amplifiers and other components, making it difficult to realize the miniaturization of the system. The quantum system including diamond nitrogen vacancy color center can realize microwave receiving and sensing through the quantum effect of electron spin transition, and has the technical characteristics of direct demodulation, anti-electromagnetic interference, not limited by Chu limit, multi-band, large dynamic range, high sensitivity; it expands new technical means for microwave receivers, supports the development and application of quantum microwave receivers, and will also bring new development opportunities to the fields of wireless radio applications such as communication, radar, electromagnetic spectrum monitoring, etc. SUMMARY

[0003] The present application needs to solve the technical problem of providing a multi-band microwave superheterodyne receiver based on a quantum system.

[0004] To solve the above technical problems, the present application provides a multi-band microwave superheterodyne receiver based on a solid-state quantum system, which adopts the following technical solutions:

[0005] The multi-band microwave superheterodyne receiver comprises a diamond, a light source, a dichroic mirror, a photodetector, a control and processing system, an antenna, a reference microwave source, a two-way power divider, a waveguide, a magnetic field generating and adjusting device;

[0006] The diamond is a granular, thin film or block diamond material containing nitrogen vacancy color centers;

[0007] The magnetic field generating and adjusting device generates a magnetic field and adjusts the direction of the magnetic field to be parallel to the nitrogen vacancy color center axis in the diamond to change its working frequency;

[0008] The light source is a green LED or laser light source, and the green light signal is reflected by the dichroic mirror and irradiated onto the diamond to excite a red fluorescent signal; the fluorescent signal is transmitted by the dichroic mirror and separated from the green light signal and irradiated onto the photodetector;

[0009] The photodetector converts the red fluorescent signal into an electrical signal, which is received by the control and processing system;

[0010] The antenna is a super wideband antenna group that receives the microwave signal to be measured;

[0011] The dual-path power divider is a wideband dual-path power divider that combines the microwave signal to be measured received by the antenna with the reference microwave signal emitted by the reference microwave source and sends them to the waveguide;

[0012] The waveguide is a super wideband waveguide that converts the received microwave signal into a local alternating magnetic field matching the size of the diamond, and the diamond installed at the local alternating magnetic field detects it; the microwave signal to be measured and the reference microwave signal are mixed on the diamond to generate an intermediate frequency signal and convert it into a fluorescent signal; in the case of microwave signal feeding, the fluorescent signal excited on the diamond will change in intensity, and the control and processing system reads the electrical signal from the photodetector, processes and solves it to obtain the characteristic parameters of the microwave.

[0013] Further, the magnetic field generating and adjusting device is composed of a coil and a permanent magnet, which generates a magnetic field and adjusts the direction of the magnetic field to be parallel to the nitrogen vacancy color center axis in the diamond, the permanent magnet is used to realize large-scale adjustment of the working frequency of the nitrogen vacancy color center, and the coil is used to realize small-scale rapid adjustment of the working frequency of the nitrogen vacancy color center; the coil and the permanent magnet can act on the diamond simultaneously or individually.

[0014] Further, the permanent magnet is a magnet array composed of magnetic blocks of different materials, and the magnetic field strength meets the requirements of regulating the working frequency of the nitrogen vacancy color center in the diamond.

[0015] Further, it further includes a one-dimensional displacement stage, which is an electrically controlled precision displacement stage, used to install the magnetic field generating and adjusting device.

[0016] Further, the control and processing system outputs a control signal for controlling the light source, the reference microwave source, and the coil module, and the specific process includes: controlling the light source to output continuous light or a specific pulsed light sequence, so that the nitrogen vacancy color center in the diamond realizes different induction modes; controlling the one-dimensional translation table to change the distance between the permanent magnet fixed thereon and the diamond, to adjust the magnetic field strength of the permanent magnet applied to the nitrogen vacancy color center in the diamond, thereby realizing large-range adjustment of the working frequency thereof; controlling the current output to the coil, to adjust the magnetic field strength of the coil applied to the nitrogen vacancy color center in the diamond, thereby realizing small-range and rapid adjustment of the working frequency thereof; and controlling the frequency and phase information output by the reference microwave source, so that the microwave signal received by the antenna and the reference microwave source are mixed on the diamond nitrogen vacancy color center, to generate an intermediate frequency signal within the response bandwidth of the diamond nitrogen vacancy color center, and the intermediate frequency signal is converted into a fluorescence signal for detection.

[0017] According to the above technical solution, the present application has the following advantages:

[0018] The present application provides a multi-band microwave superheterodyne receiver based on a solid-state quantum system. Firstly, the receiver can realize the detection of microwave signals in the range of 0-100GHz by using a single receiver device, by regulating the ground state energy level of the diamond nitrogen vacancy color center through the combination of a permanent magnet and a coil. Secondly, the accurate detection of the frequency and phase of the to-be-detected microwave can be realized through the mixing process of the to-be-detected microwave and the reference microwave acting on the diamond nitrogen vacancy color center at the same time. Thirdly, the receiver detects the microwave based on the optical detection of magnetic resonance, and the microwave sensing front end is made of non-metallic materials, so that the dynamic range of the detection strength is large. Finally, the receiver does not have complex links such as amplification, frequency conversion, and filtering in the traditional microwave receiver, so that the system is simple. Moreover, the receiver does not need complex supporting devices such as low-temperature refrigeration and laser frequency locking, and is easy to integrate. The present application can be applied to microwave quantum radar to obtain wide-spectrum and large-dynamic target echo information, and obtain better detection performance than traditional radar. The present application can also be applied in the fields of frequency-agile wireless communication and electromagnetic spectrum detection. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 The figure is a structural schematic diagram of the multi-band microwave superheterodyne receiver based on a solid-state quantum system of the embodiment of the present application. DETAILED DESCRIPTION

[0020] The specific embodiment of the present application will be described in detail below in combination with the drawings and examples.

[0021] As Figure 1As shown, in the embodiment, the multi-band microwave superheterodyne receiver based on solid-state quantum system comprises a diamond 1, a light source 2, a dichroic mirror 3, a photodetector 4, a control and processing system 5, an antenna 6, a reference microwave source 7, a two-way power divider 8, a waveguide 9, a coil 10, a permanent magnet 11, and a one-dimensional displacement table 12.

[0022] The diamond 1 is a granular, thin-film or block diamond material containing nitrogen vacancy color centers; the light source 2 is a green LED or a laser light source, and the green light signal emitted therefrom is reflected by the dichroic mirror 3 to irradiate the diamond 1 to excite a red fluorescent signal; the fluorescent signal is transmitted by the dichroic mirror 3 to separate from the green light signal and irradiate the photodetector 4; in order to improve the signal-to-noise ratio of detection, an auxiliary optical system can be added between the light source 2 and the diamond 1 to modulate and improve the irradiation efficiency of the light source; a notch filter, a long-pass filter, an optical stop and other optical components can be added in the light path in front of the photodetector 4 to filter out the influence of green light and other stray light; the photodetector 4 is a high-sensitivity photodetector sensitive to the red fluorescent signal, which converts the red fluorescent signal into an electrical signal received by the control and processing system 5; the antenna 6 is a super-wideband antenna group capable of receiving a to-be-measured microwave signal in a frequency range of 0-100 GHz in space; the two-way power divider 8 is a wideband two-way power divider, which combines the to-be-measured microwave signal received by the antenna 6 with the reference microwave signal emitted by the reference microwave source 7 and sends them to the waveguide 9; the waveguide 9 is a super-wideband waveguide, which converts the received microwave signal into a local alternating magnetic field matching the size of the diamond, and the diamond 1 installed at the local alternating magnetic field detects the signal; the to-be-measured microwave signal and the reference microwave signal are mixed on the diamond to generate an intermediate frequency signal and convert it into a fluorescent signal, thereby realizing the measurement of the frequency, phase and other information of the to-be-measured microwave signal; in the case of microwave signal feeding, the intensity of the fluorescent signal excited on the diamond 1 changes, the control and processing system 5 reads the electrical signal from the photodetector 4, processes and solves it, and obtains the characteristic parameters of the microwave; in order to improve the signal-to-noise ratio of detection, a transimpedance amplifier, a lock-in amplifier and the like can be added behind the photodetector 4 for signal enhancement.

[0023] The permanent magnet 11 is a magnet array composed of magnetic blocks of different materials, and the magnetic field strength can meet the requirements of regulating the working frequency of the nitrogen vacancy color center in the diamond 1 to realize the detection of 0-100 GHz microwave signals; the one-dimensional displacement table 12 is an electrically controlled precision displacement table, which can control the distance between the diamond and the permanent magnet fixed on the one-dimensional displacement table according to the control signal generated by the control and processing system.

[0024] The coil 10 and the permanent magnet 11 generate a magnetic field and adjust the direction of the magnetic field to be parallel to the axis of the nitrogen vacancy color center in the diamond 1 to change its working frequency. The working frequency of the nitrogen vacancy color center axis in the diamond 1 and the magnetic field strength applied to the nitrogen vacancy color center in the diamond 1 are related as follows: f± =f0±γ NV ·B / / In the formula, f ± To correspond to the operating frequency of a certain nitrogen-vacancy color center, f0 is the operating frequency of the diamond nitrogen-vacancy color center under zero magnetic field conditions, which is 2.87 GHz. NV The gyromagnetic ratio of the electron spin of the nitrogen-vacancy color center is 28 MHz / mT, B / / To apply a magnetic field along the axis of the nitrogen vacancy color center, coil 10 and permanent magnet 11 can act on diamond 1 simultaneously or individually.

[0025] The control and processing system 5 outputs control signals to control modules such as the light source 2, reference microwave source 7, coil 10, and one-dimensional displacement stage 12. Specifically, the process includes: controlling the light source 2 to output continuous light or a specific pulse light sequence, enabling different sensing modes for the nitrogen-vacancy color centers in the diamond 1; controlling the one-dimensional displacement stage 12 to change the distance between the permanent magnet 11 fixed on it and the diamond 1, thereby adjusting the magnetic field strength applied by the permanent magnet 11 to the nitrogen-vacancy color centers in the diamond 1, thus achieving a wide range of frequency adjustment; controlling the current output to the coil 10, which also adjusts the magnetic field strength applied by the coil 10 to the nitrogen-vacancy color centers in the diamond 1, achieving a small range of rapid frequency adjustment; and controlling the frequency and phase information output by the reference microwave source 7, causing it to mix with the microwave signal received by the antenna 6 at the diamond nitrogen-vacancy color centers to generate an intermediate frequency signal within the response bandwidth of the diamond nitrogen-vacancy color centers, which is then converted into a fluorescence signal for detection.

Claims

1. A multi-band microwave superheterodyne receiver based on a solid-state atomic system, characterized in that: It comprises diamond (1), light source (2), dichroic mirror (3), photoelectric detector (4), control and processing system (5), antenna (6), reference microwave source (7), two-way power divider (8), waveguide (9), magnetic field generating and adjusting device; The diamond (1) is granular, film or block diamond material containing nitrogen vacancy color centers; The magnetic field generating and adjusting device generates magnetic field and adjusts the direction of the magnetic field to be parallel to the nitrogen vacancy color center axis in the diamond (1) to change the working frequency thereof; The light source (2) is green LED or laser light source, and the green light signal emitted is reflected by the dichroic mirror (3) and irradiated onto the diamond (1) to excite red fluorescent signal; the fluorescent signal is transmitted through the dichroic mirror (3) and separated from the green light signal and irradiated onto the photoelectric detector (4); The photoelectric detector (4) converts the red fluorescent signal into electric signal which is received by the control and processing system (5); The antenna (6) is a super wideband antenna group receiving the microwave signal to be measured; The two-way power divider (8) is a wideband two-way power divider, which combines the microwave signal to be measured received by the antenna (6) with the reference microwave signal emitted by the reference microwave source (7) and sends them to the waveguide (9); The waveguide (9) is an ultra-wideband waveguide, which converts the received microwave signal into a local alternating magnetic field matching the size of the diamond (1), and is detected by the diamond (1) installed at the local alternating magnetic field. The to-be-measured microwave signal and the reference microwave signal are mixed on the diamond (1) to generate an intermediate frequency signal and convert it into a fluorescent signal. In the case of microwave signal feeding, the intensity of the fluorescent signal excited on the diamond (1) will change. The control and processing system (5) reads the electrical signal from the photodetector (4), processes and solves it to obtain the characteristic parameters of the microwave. The magnetic field generating and adjusting device is composed of a coil (10) and a permanent magnet (11), which generates a magnetic field and adjusts the direction of the magnetic field to be parallel to the nitrogen vacancy color center axis in the diamond (1). The permanent magnet (11) is used to realize large-range adjustment of the working frequency of the nitrogen vacancy color center, and the coil (10) is used to realize small-range and rapid adjustment of the working frequency of the nitrogen vacancy color center. The coil (10) and the permanent magnet (11) can act on the diamond (1) simultaneously or individually. The control and processing system (5) outputs a control signal for controlling the light source (2), the reference microwave source (7), and the coil (10) module. The specific process includes: controlling the light source (2) to output continuous light or a specific pulse light sequence, so that the nitrogen vacancy color center in the diamond (1) realizes different induction modes; controlling the one-dimensional translation stage (12) to change the distance between the permanent magnet (11) fixed thereon and the diamond (1), adjusting the magnetic field strength of the permanent magnet (11) applied to the nitrogen vacancy color center in the diamond (1), and then realizing large-range adjustment of the working frequency thereof; controlling the current output to the coil (10), adjusting the magnetic field strength of the coil (10) applied to the nitrogen vacancy color center in the diamond (1), and realizing small-range and rapid adjustment of the working frequency thereof; and controlling the frequency and phase information output by the reference microwave source (7) so that it is mixed with the microwave signal received by the antenna (6) on the diamond nitrogen vacancy color center to generate an intermediate frequency signal within the response bandwidth of the diamond nitrogen vacancy color center, and convert it into a fluorescent signal for detection.

2. A multi-band microwave superheterodyne receiver based on solid state atomic system according to claim 1, characterized in that, The permanent magnet (11) is a magnet array composed of magnetic blocks of different materials, and the magnetic field strength meets the regulation requirements of the working frequency of the nitrogen vacancy color center in the diamond (1).

3. A multi-band microwave superheterodyne receiver based on solid-state atomic systems according to claim 1 or 2, characterized in that, The one-dimensional translation stage (12) is an electrically controlled precision displacement stage used for installing the magnetic field generating and adjusting device.

4. A multi-band microwave superheterodyne receiver based on solid state atomic systems as claimed in claim 1, wherein: An auxiliary optical system is added between the light source (2) and the diamond (1) to modulate and improve the illumination efficiency of the light source.

5. A multi-band microwave superheterodyne receiver based on a solid-state atomic system as described in claim 1, characterized in that: A notch filter, a long-pass filter, and an optical stop optical assembly are added in the front light path of the photodetector (4) to filter out the influence of green light and other wavelength stray light.

6. The multi-band microwave superheterodyne receiver based on a solid-state atomic system as described in claim 1, characterized in that: A transimpedance amplifier and a lock-in amplifier are added after the photodetector (4) to enhance the signal.

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