Coherence enhanced microwave receiving system and method

Abstract

The invention provides a coherent enhanced microwave receiving system and method, in the microwave receiving system, probe light enters an atomic gas chamber and is used for exciting atoms in the atomic gas chamber from a ground state energy level to a metastable state energy level, coupling light enters the atomic gas chamber and coincides with the probe light, and the probe light is used for exciting the atoms in the atomic gas chamber from the ground state energy level to the metastable state energy level. The coupled light is used for exciting atoms from a metastable state energy level to a first Rydberg energy level; the microwave system is arranged to apply a pulsed microwave field to the atomic gas chamber in a first working mode for exciting atoms from a first Rydberg energy level to a second Rydberg energy level so as to enhance coherence between excitation of the first Rydberg energy level and excitation of the second Rydberg energy level; and the microwave system is set to apply a continuous local oscillation microwave field to the atomic gas chamber in a second working mode, and the continuous local oscillation microwave field and the to-be-detected microwave field jointly cause the energy level periodic change of atoms, so that the intensity of the detection light is periodically modulated. By adopting the microwave receiving system provided by the invention, the coherence time of the atomic Rydberg state can be prolonged, and the microwave receiving performance is improved.

Description

Technical Field

[0001] The present application relates to the technical field of microwave reception, and particularly to a microwave reception system and method with enhanced coherence. Background Art

[0002] Microwave reception technology can be used in fields such as radar detection, wireless communication, medical diagnosis, and geological exploration. Microwave reception technology based on Rydberg atoms utilizes the response of highly excited atoms to an external microwave electric field to achieve the reception and measurement of microwaves, and has the advantages of high microwave reception sensitivity and a wide frequency range. Atoms are the core components in this new technology and are used to sense the ambient microwave field. The quantum states of the atoms participating in the microwave interaction in the atomic gas cell directly affect the microwave reception sensitivity. Therefore, it is very important to improve the coherence of Rydberg atoms. Under normal circumstances, atoms are excited to the initial Rydberg energy level, and the transition between adjacent Rydberg energy levels resonates with the microwave field to be measured. However, the coherence between two Rydberg energy levels is a bottleneck problem faced in improving microwave reception sensitivity.

[0003] Therefore, there is an urgent need for a method to increase the coherence of Rydberg energy levels, so as to achieve high-sensitivity microwave reception. Summary of the Invention

[0004] To solve the above technical problems, the present application proposes a microwave reception system and method with enhanced coherence, which can achieve high-sensitivity reception of a microwave field.

[0005] To solve the above technical problems, the present application proposes a microwave reception system with enhanced coherence. The microwave reception system includes a first laser, an atomic gas cell, a second laser, a photodetector, a microwave system, and a host computer;

[0006] The probe light generated by the first laser is incident into the atomic gas cell and is used to excite the atoms in the atomic gas cell from the ground state energy level to the metastable state energy level. The coupling light generated by the second laser is incident into the atomic gas cell and coincides with the probe light. The coupling light is used to excite the atoms from the metastable state energy level to the first Rydberg energy level;

[0007] The microwave system is configured to apply a pulsed microwave field to the atomic gas cell in a first operating mode. The pulsed microwave field is used to excite the atoms from the first Rydberg energy level to the second Rydberg energy level to enhance the coherence between the excitation from the first Rydberg energy level to the second Rydberg energy level. The microwave system is configured to apply a continuous local oscillator microwave field to the atomic gas cell in a second operating mode. The continuous local oscillator microwave field and the microwave field to be measured jointly cause a periodic change in the energy levels of the atoms, and thereby periodically modulate the intensity of the probe light;

[0008] The photodetector is used to detect the detection light emitted from the atomic gas cell, and the host computer calculates the field strength information of the microwave field to be measured based on the intensity of the detection light.

[0009] Wherein, the pulsed microwave field is a π / 2 pulsed microwave field.

[0010] Wherein, the amplitude of the pulsed microwave field is greater than the amplitude of the continuous local oscillator microwave field.

[0011] Wherein, the host computer controls the microwave system to periodically execute the first working mode and the second working mode.

[0012] Wherein, the atom is a rubidium atom, the ground state energy level is 5S 1 / 2 , F = 2 fine energy level, the metastable energy level is 5P 3 / 2 , F` = 3 fine energy level, the first Rydberg energy level is 87D 5 / 2 energy level, the second Rydberg energy level is 86P 3 / 2 energy level.

[0013] Wherein, the microwave receiving system further includes a dichroic mirror, the dichroic mirror is disposed between the atomic gas cell and the photodetector, the first laser is located on a side of the atomic gas cell away from the dichroic mirror, the detection light emitted from the atomic gas cell is transmitted through the dichroic mirror to the photodetector, and the coupling light emitted from the second laser is reflected by the dichroic mirror to the atomic gas cell and is transmitted in a coincident manner with the detection light in the atomic gas cell.

[0014] To solve the above technical problems, the present application also proposes a coherent enhanced microwave receiving method, the method includes:

[0015] Using the detection light to excite the atoms in the atomic gas cell from the ground state energy level to the metastable energy level;

[0016] Using the coupling light to excite the atoms from the metastable energy level to the first Rydberg energy level;

[0017] Applying a pulsed microwave field to the atomic gas cell in the first working mode to excite the atoms from the first Rydberg energy level to the second Rydberg energy level;

[0018] Applying a continuous local oscillator microwave field to the atomic gas cell in the second working mode, wherein the continuous local oscillator microwave field and the microwave field to be measured jointly cause a periodic change in the energy level of the atoms, and further generate a periodic modulation on the intensity of the detection light;

[0019] Detecting the detection light emitted from the atomic gas cell;

[0020] Calculate the field strength information of the microwave field to be measured based on the intensity of the detection light.

[0021] Wherein, the method further includes periodically executing the first working mode and the second working mode.

[0022] Compared with the prior art, the beneficial effects of the present application are as follows: The microwave receiving system provided by the present application includes a first laser, an atomic gas cell, a second laser, a photodetector, a microwave system, and a host computer; the detection light generated by the first laser is incident on the atomic gas cell and is used to excite the atoms in the atomic gas cell from the ground state energy level to the metastable energy level, the coupling light generated by the second laser is incident on the atomic gas cell and coincides with the detection light, and the coupling light is used to excite the atoms from the metastable energy level to the first Rydberg energy level; the microwave system is configured to apply a pulsed microwave field to the atomic gas cell in the first working mode, and the pulsed microwave field is used to excite the atoms from the first Rydberg energy level to the second Rydberg energy level to enhance the coherence between the first Rydberg energy level and the second Rydberg energy level; the microwave system is configured to apply a continuous local oscillator microwave field to the atomic gas cell in the second working mode, and the continuous local oscillator microwave field and the microwave field to be measured jointly cause a periodic change in the energy level of the atoms, thereby generating a periodic modulation of the intensity of the detection light; the photodetector is used to detect the detection light emitted from the atomic gas cell, and the host computer calculates the field strength information of the microwave field to be measured based on the intensity of the detection light. By using the microwave receiving system of the present application, the coherence time of the atomic Rydberg state can be increased, and the microwave receiving performance can be improved. Description of the Drawings

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0024] Wherein:

[0025] Figure 1 is a schematic structural diagram of an embodiment of the coherent enhanced microwave receiving system provided by the present application;

[0026] Figure 2 is a schematic structural diagram of another embodiment of the coherent enhanced microwave receiving system provided by the present application;

[0027] Figure 3 is a schematic flowchart of an embodiment of the coherent enhanced microwave receiving method provided by the present application;

[0028] Figure 4 It is a schematic diagram of the overall process of the coherent enhancement microwave receiving method provided by this application. Detailed implementation manners

[0029] Next, the technical solutions in the embodiments of this application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of this application.

[0030] The terms "first", "second", "third", "fourth", etc. (if any) in the specification, claims and the above accompanying drawings of this application are used to distinguish similar objects, and do not necessarily need to be used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of this application described here, for example, can be implemented in an order different from those illustrated or described here. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0031] This application provides a coherent enhancement microwave receiving system. For details, please refer to Figure 1 , Figure 1 It is a schematic diagram of the structure of an embodiment of the coherent enhancement microwave receiving system provided by this application.

[0032] As Figure 1 shown, the microwave receiving system 100 provided by this application includes: a first laser 11, an atomic gas cell 12, a second laser 13, a photodetector 14, a microwave system 15, and a host computer 16.

[0033] The atomic gas cell 12 involved in the embodiments of this application is encapsulated with gaseous alkali metal atoms and can achieve omnidirectional microwave reception.

[0034] The probe light generated by the first laser 11 is incident into the atomic gas cell 12 and is used to excite the atoms in the atomic gas cell 12 from the ground state energy level to the metastable energy level. The coupling light generated by the second laser 13 is incident into the atomic gas cell 12 and coincides with the probe light. The coupling light is used to excite the atoms from the metastable energy level to the first Rydberg energy level.

[0035] Both the probe light and the coupling light involved in the embodiments of this application are linearly polarized lights and have the same polarization direction.

[0036] The microwave system 15 is configured to apply a pulsed microwave field to the atomic gas cell 12 in the first operating mode. The pulsed microwave field is used to excite atoms from the first Rydberg energy level to the second Rydberg energy level, so as to enhance the coherence between the first Rydberg energy level and the second Rydberg energy level and establish the maximum coherence between the two Rydberg states.

[0037] In the embodiment of the present application, the pulsed microwave field is a π / 2 pulsed microwave field, and the amplitude of the pulsed microwave field should be greater than the amplitude of the continuous local oscillator microwave field.

[0038] The microwave system 15 is configured to apply a continuous local oscillator microwave field to the atomic gas cell 12 in the second operating mode. The continuous local oscillator microwave field and the microwave field to be measured jointly cause a periodic change in the energy level of the atoms, and then produce a periodic modulation on the intensity of the probe light; the power of the modulation signal is proportional to the power of the microwave to be measured, thereby realizing the measurement of the microwave to be measured.

[0039] The photodetector 14 is used to detect the probe light emitted from the atomic gas cell 12, and the upper computer 16 calculates the field strength information of the microwave field to be measured based on the intensity of the probe light.

[0040] Specifically, the photodetector 14 measures the light intensity of the probe light emitted from the atomic gas cell 12, converts it into an electrical signal and provides it to the upper computer 16. The power of the probe light modulation signal is proportional to the power of the microwave to be measured, thereby realizing the measurement of the microwave to be measured.

[0041] The upper computer 16 controls the signal source, that is, the microwave system 15 generates the timing of the π / 2 pulsed microwave field and the continuous local oscillator microwave field, and realizes periodic coherence enhancement and microwave detection, that is, the upper computer 16 controls the microwave system 15 to periodically execute the first operating mode and the second operating mode.

[0042] Specifically, the upper computer 16 controls the microwave system 15 to first generate a π / 2 pulsed microwave field, transfer the atoms in the initial Rydberg state to the adjacent Rydberg state, and establish the maximum coherence between the two Rydberg states. Subsequently, the microwave system 15 generates a continuous local oscillator microwave field, which jointly causes a periodic change in the atomic energy level with the microwave field to be measured, thereby generating a periodic modulation on the intensity of the probe light. The power of the modulation signal is proportional to the power of the microwave to be measured, thereby realizing the measurement of the microwave to be measured. In a specific embodiment, the microwave generated by the microwave system 15 resonates with the transitions of the Rydberg states 87D 5 / 2 and 86P 3 / 2 and the antenna uses a standard horn antenna.

[0043] Specifically, the atom is a rubidium atom, the ground state energy level is 5S 1 / 2 , F = 2 fine energy level, the metastable energy level is 5P 3 / 2 , F` = 3 fine energy level, the first Rydberg energy level is 87D 5 / 2 energy level, and the second Rydberg energy level is 86P3 / 2 Energy level.

[0044] Please continue to refer to Figure 2 , Figure 2 which is a schematic structural diagram of another embodiment of the coherent enhanced microwave receiving system provided by this application.

[0045] Based on Figure 1 the coherent enhanced microwave receiving system 100 shown, the microwave receiving system 100 protected by this application further includes a dichroic mirror 17, and the dichroic mirror 17, that is, a dichroic mirror, is disposed between the atomic gas cell 12 and the photodetector 14. The first laser 11 is located on the side of the atomic gas cell 12 away from the dichroic mirror 17, and the detection light emitted from the atomic gas cell 12 is transmitted through the dichroic mirror 17 to the photodetector 14. The coupling light emitted by the second laser 13 is reflected by the dichroic mirror 17 to the atomic gas cell 12 and travels in opposite directions to the detection light in the atomic gas cell 12 in a coincident manner.

[0046] Specifically, the dichroic mirror 17 involved in the embodiments of this application transmits the detection light and reflects the coupling light. Among them, the first laser 11, the atomic gas cell 12, the dichroic mirror 17, and the photodetector 14 are on the same axis.

[0047] Specifically, the output end of the first laser 11 is connected to the atomic gas cell 12, and the coupling light generated by the second laser 13 is connected to the atomic gas cell 12 through the dichroic mirror 17. Among them, the atomic gas cell 12 is filled with gaseous alkali metal atoms and can realize omnidirectional space microwave field reception. The output end of the atomic gas cell 12 is connected to the input end of the photodetector 14. The output end of the photodetector 14 is connected to the input end of the upper computer 16. The output end of the upper computer 16 is connected to the input ends of the first laser 11, the second laser 13, and the microwave system 15.

[0048] In this application, the detection light generated by the first laser 11 resonates with the atomic ground state and metastable energy level transitions, and the coupling light generated by the second laser 13 resonates with the atomic excited state and Rydberg energy level transitions. The detection light and the coupling light travel in opposite directions and coincide in the atomic gas cell 12 to excite the atoms to the Rydberg state. The upper computer 16 controls the microwave system 15 to first generate a π / 2 pulse microwave field to transfer the atoms in the initial Rydberg state to the adjacent Rydberg state and establish the maximum coherence between the two Rydberg states. Subsequently, the microwave system 15 generates a continuous local oscillator microwave field, which together with the microwave field to be measured causes a periodic change in the atomic energy level, thereby generating a periodic modulation in the detection light intensity. The power of the modulation signal is proportional to the power of the microwave to be measured, thereby realizing the measurement of the microwave to be measured.

[0049] The microwave receiving system provided in the present application includes a first laser, an atomic gas chamber, a second laser, a photodetector, a microwave system and a host computer; the detection light generated by the first laser is incident into the atomic gas chamber and is used to excite the atoms in the atomic gas chamber from the ground state energy level to the metastable energy level, the coupling light generated by the second laser is incident into the atomic gas chamber and coincides with the detection light, and the coupling light is used to excite the atoms from the metastable energy level to the first Rydberg energy level; the microwave system is configured to apply a pulsed microwave field to the atomic gas chamber in a first working mode, the pulsed microwave field is used to excite the atoms from the first Rydberg energy level to the second Rydberg energy level, so as to enhance the coherence between the excitation from the first Rydberg energy level to the second Rydberg energy level; the microwave system is configured to apply a continuous local oscillator microwave field to the atomic gas chamber in a second working mode, the continuous local oscillator microwave field and the microwave field to be measured jointly cause the energy level of the atoms to change periodically, thereby producing periodic modulation on the intensity of the detection light; the photodetector is used to detect the detection light emitted from the atomic gas chamber, and the host computer calculates the field strength information of the microwave field to be measured based on the intensity of the detection light. By using the microwave receiving system of the present application, the coherence time of the atomic Rydberg state can be increased and the microwave receiving performance can be improved.

[0050] The advantages of this application compared with the prior art are:

[0051] (1) The microwave electric field measurement technology based on Rydberg atoms currently does not consider the influence of the atomic coherence of the Rydberg energy level on the microwave reception sensitivity. After completing the atomic excitation, the present invention uses a microwave π / 2 pulse to prepare the atoms to the maximum coherence state composed of the initial Rydberg state and the adjacent Rydberg state, thereby improving the atomic coherence of the Rydberg state, thereby achieving high-sensitivity microwave reception.

[0052] (2) The present application uses the same signal source to generate microwave π / 2 pulses and continuous local oscillator microwave fields in a time-sharing manner, which are used to prepare atomic maximum coherence states and superheterodyne mode microwave measurements, respectively, and can simplify the system structure.

[0053] based on Figure 1 and Figure 2 The present application further proposes a related microwave receiving method. For details, please continue to refer to Figure 3 and 4 , Figure 3 is a flow chart of an embodiment of a coherent enhanced microwave receiving method provided by the present application, Figure 4 It is a schematic diagram of the overall process of the coherently enhanced microwave receiving method provided in the present application.

[0054] like Figure 3 As shown, the microwave receiving method of the present application comprises the following steps:

[0055] Step S31: Use the probe light to excite the atoms in the atomic gas cell from the ground energy level to the metastable energy level.

[0056] Step S32: Use the coupling light to excite the atoms from the metastable energy level to the first Rydberg energy level.

[0057] Step S33: Apply a pulsed microwave field to the atomic gas cell in the first operating mode to excite the atoms from the first Rydberg energy level to the second Rydberg energy level.

[0058] Step S34: Apply a continuous local oscillator microwave field to the atomic gas cell in the second operating mode, where the continuous local oscillator microwave field and the microwave field to be measured jointly cause a periodic change in the energy level of the atoms, thereby producing a periodic modulation of the intensity of the probe light.

[0059] Step S35: Detect the probe light emitted from the atomic gas cell.

[0060] Step S36: Calculate the field strength information of the microwave field to be measured based on the intensity of the probe light.

[0061] Those skilled in the art can understand that in the above method of the specific implementation manner, the writing order of each step does not mean a strict execution order that constitutes any limitation to the implementation process. The specific execution order of each step should be determined by its function and possible internal logic.

[0062] The above is only the implementation manner of the present application, and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present application, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of the present application.

Claims

1. A coherent enhanced microwave receiving system, characterized in that The microwave receiving system comprises a first laser, an atomic gas chamber, a second laser, a photoelectric detector, a microwave system and a host computer; The detection light generated by the first laser is incident into the atomic gas chamber and is used to excite the atoms in the atomic gas chamber from the ground state energy level to the metastable state energy level. The coupling light generated by the second laser is incident into the atomic gas chamber and overlaps with the detection light. The coupling light is used to excite the atoms from the metastable state energy level to the first Rydberg energy level. The microwave system is configured to apply a pulsed microwave field to the atomic gas chamber in a first working mode, wherein the pulsed microwave field is used to excite the atoms from the first Rydberg energy level to the second Rydberg energy level so as to enhance the coherence between the excitation of the first Rydberg energy level to the second Rydberg energy level; The microwave system is configured to apply a continuous local oscillator microwave field to the atomic gas chamber in the second working mode, wherein the continuous local oscillator microwave field and the microwave field to be measured together cause a periodic change in the energy level of the atoms, thereby periodically modulating the intensity of the detection light; The photoelectric detector is used to detect the detection light emitted from the atomic gas chamber, and the host computer calculates the field intensity information of the microwave field to be measured based on the intensity of the detection light.

2. The microwave receiving system according to claim 1, wherein The pulse microwave field is a π / 2 pulse microwave field.

3. The microwave receiving system according to claim 1, wherein The amplitude of the pulse microwave field is greater than the amplitude of the continuous local oscillation microwave field.

4. The microwave receiving system according to claim 1, wherein The host computer controls the microwave system to periodically execute the first working mode and the second working mode.

5. The microwave receiving system according to claim 1, characterized in that, The atom is a rubidium atom, and the ground state energy level is 5S 1 / 2 , the fine energy level of F = 2, and the metastable energy level is 5P 3 / 2 , the fine energy level of F` = 3, and the first Rydberg energy level is 87D 5 / 2 energy level, and the second Rydberg energy level is 86P 3 / 2 energy level.

6. The microwave receiving system according to claim 1, wherein The microwave receiving system also includes a dichroic mirror, which is arranged between the atomic gas chamber and the photodetector. The first laser is located on the side of the atomic gas chamber away from the dichroic mirror. The detection light emitted from the atomic gas chamber is transmitted to the photodetector through the dichroic mirror. The coupling light emitted by the second laser is reflected to the atomic gas chamber through the dichroic mirror and transmitted in opposite directions in the atomic gas chamber in an overlapping manner with the detection light.

7. A coherent enhancement microwave receiving method, characterized in that The method comprises: The probe light is used to excite the atoms in the atomic gas cell from the ground state energy level to the metastable state energy level; Exciting the atom from the metastable energy level to the first Rydberg energy level using coupled light; applying a pulsed microwave field to the atomic gas cell in a first operating mode to excite the atoms from the first Rydberg energy level to a second Rydberg energy level; Applying a continuous local oscillator microwave field to the atomic gas chamber in a second working mode, wherein the continuous local oscillator microwave field and the microwave field to be measured together cause a periodic change in the energy level of the atoms, thereby periodically modulating the intensity of the detection light; detecting the detection light emitted from the atomic gas chamber; The field intensity information of the microwave field to be measured is calculated based on the intensity of the detection light.

8. The microwave receiving method according to claim 7, wherein The method further includes periodically executing the first working mode and the second working mode.

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