A high-sensitivity microwave receiving system and method with atomic polarization enhancement

Abstract

The application discloses a high-sensitivity microwave receiving system and method with atomic polarization enhancement, and the system comprises a first laser, an atomic gas chamber, a second laser, a dichroic mirror, a photodetector, a first signal source, a second signal source, a first antenna, a second antenna and a host computer. The method is characterized in that: the first signal source is used to generate a pulsed microwave field to prepare an atomic initial state to a specific ground state; the first laser is used to generate detection light which is resonant with an atomic ground state and a metastable state energy level transition; the second laser is used to generate coupling light which is resonant with an atomic excited state and a Rydberg state energy level transition; the detection light and the coupling light are used to excite the atom to the Rydberg state; the second signal source is used to generate a microwave field which is jointly used to cause periodic changes of atomic energy levels, and the microwave field is used to generate periodic modulation on the intensity of the detection light; the power of the modulation signal is proportional to the power of a to-be-measured microwave, and the to-be-measured microwave receiving measurement is realized. The atomic polarization enhancement method can increase the number of atoms participating in the microwave measurement, and improve the microwave receiving performance.

Description

Technical Field

[0001] This invention relates to a microwave receiving system and method, and more particularly to a highly sensitive microwave receiving system and method with enhanced atomic polarization, belonging to the field of microwave receiving technology. Background Technology

[0002] Microwave receiving technology has applications in target detection, wireless communication, medical diagnosis, geological surveys, and archaeological research. Rydberg atom-based microwave receiving technology utilizes the response of highly excited atoms to external microwave electric fields to receive and measure microwaves. Its measurement limit can surpass the traditional thermal noise limit, thus promising high-sensitivity microwave receiving capabilities exceeding those of traditional antennas. The atomic gas cell is a crucial component of a microwave receiving system, used in sensitive microwave fields. The number of atoms participating in microwave interaction within the atomic gas cell directly affects the microwave receiving sensitivity; therefore, increasing the number of Rydberg state atoms is essential. Since atoms are typically uniformly distributed across the ground state energy level, the number of atoms pumped to the Rydberg state by lasers is very limited, representing a bottleneck in improving microwave receiving sensitivity. Therefore, a method to increase the number of Rydberg state atoms is urgently needed to achieve highly sensitive microwave reception. Summary of the Invention

[0003] The technical problem solved by the present invention is to overcome the shortcomings of the prior art and provide a highly sensitive microwave receiving system and method with enhanced atomic polarization, which can achieve high-sensitivity reception of microwave fields.

[0004] The technical solution of this invention is:

[0005] A highly sensitive microwave receiving system with enhanced atomic polarization includes a first laser, an atomic gas cell, a second laser, a dichroic mirror, a photodetector, a first signal source, a second signal source, a first antenna, a second antenna, and a host computer.

[0006] The first signal source generates periodic π pulses under the control of the host computer, and the periodic π pulses are transmitted to the atomic gas chamber through the first antenna;

[0007] The first laser, under the control of the host computer, generates probe light that resonates with the transitions of the atomic ground state and metastable energy levels, and is incident on the atomic gas cell;

[0008] The second laser, under the control of the host computer, generates coupled light that resonates with the energy level transitions of the excited state and Rydberg state of the atom. After being reflected by the dichroic mirror, the light enters the atomic gas chamber.

[0009] The second signal source generates a local oscillator microwave field, which is transmitted to the atomic gas cell through the second antenna. The local oscillator microwave field and the microwave field to be measured together cause periodic changes in the atomic energy level, thereby generating periodic modulation in the intensity of the probe light.

[0010] The photodetector measures the intensity of the probe light emitted from the atomic gas chamber, converts it into an electrical signal, and provides it to the host computer. The power of the probe light modulation signal is proportional to the power of the microwave under test, thereby realizing the receiving and measurement of the microwave under test.

[0011] The preferred method involves encapsulating gaseous alkali metal atoms within an atomic chamber, enabling omnidirectional reception of spatial microwave fields.

[0012] Preferably, the output of the first laser is connected to the atomic gas cell, and the coupled light generated by the second laser is connected to the atomic gas cell via a dichroic mirror; the first laser, the atomic gas cell, the dichroic mirror, and the photodetector are on the same axis; the output of the atomic gas cell is connected to the input of the photodetector; the output of the photodetector...

[0013] It is connected to the input terminal of the host computer; the output terminal of the host computer is connected to the input terminals of the first laser, the second laser, and the first signal source 5.

[0014] Preferably, the dichroic mirror transmits the probe light and reflects the coupling light.

[0015] Preferably, the host computer controls the timing of the first signal source, the first laser, and the second laser to achieve periodic atomic polarization and microwave detection.

[0016] Preferably, the probe light and the coupling light are linearly polarized light, and have the same polarization direction.

[0017] 0. A highly sensitive microwave receiving method with enhanced atomic polarization, comprising:

[0018] The host computer controls the frequency and waveform of the microwave field generated by the first signal source to generate π pulses; the π pulses are transmitted to the atomic gas cell through the first antenna, preparing the atoms in the atomic gas cell to a specific ground state and realizing the initial state polarization of the atoms;

[0019] By using lasers to pump atoms in a specific ground state to a Rydberg state, the number of effective atoms interacting with microwaves is increased.

[0020] The host computer controls the first laser to generate probe light that resonates with the transition between the ground state and metastable state energy levels of the atom, and controls the second laser to generate coupling light that resonates with the transition between the excited state and Rydberg state energy levels of the atom. The probe light and the coupling light are transmitted in opposite directions and coincide in the atomic gas chamber, exciting the atom to the Rydberg state.

[0021] The second signal source generates a local oscillator microwave field, which is transmitted to the atomic gas cell through the second antenna. The local oscillator microwave field and the microwave field to be measured together cause periodic changes in the atomic energy levels in the atomic gas cell, thereby generating periodic modulation of the probe light intensity and obtaining the probe light modulation signal.

[0022] The modulation signal of the probe light emitted from the atomic gas cell is measured using a photodetector, and the light intensity is converted into a voltage value and then provided to the host computer.

[0023] The power of the microwave to be measured is calculated by the host computer, and a single receiving measurement is completed.

[0024] Preferably, the power of the probe light modulation signal is proportional to the power of the microwave under test.

[0025] The advantages of this invention compared to existing methods are:

[0026] (1) Current microwave electric field measurement techniques based on Rydberg atoms do not consider the effect of the effective number of atoms on microwave receiving sensitivity. In the initial state preparation stage, this invention uses microwave π pulses to concentrate atoms that were originally uniformly distributed on the ground state energy level to a specific ground state energy level, thereby increasing the number of atoms pumped to the Rydberg state by laser and thus achieving high-sensitivity microwave receiving.

[0027] (2) Traditional methods of increasing the number of atoms mainly involve heating the atomic gas chamber, which cannot increase the proportion of Rydberg state atoms and will also cause increased interatomic collisions, thereby affecting the system sensitivity. Using the method of the present invention, it is not necessary to increase the atomic density in the gas chamber. The number of atoms participating in microwave action can be increased simply by polarizing the initial state of atoms. Attached Figure Description

[0028] Figure 1 This is a block diagram of a high-sensitivity microwave receiving system with enhanced atomic polarization according to the present invention;

[0029] Figure 2 This is a flowchart of a highly sensitive microwave receiving method with enhanced atomic polarization according to the present invention. Detailed Implementation

[0030] like Figure 1 As shown, the present invention proposes a highly sensitive microwave receiving system with enhanced atomic polarization, comprising: a first laser, an atomic gas cell, a second laser, a dichroic mirror, a photodetector, a first signal source, a second signal source, a first antenna, a second antenna, and a host computer.

[0031] The output of the first laser is connected to the atomic gas cell. The coupled light generated by the second laser is connected to the atomic gas cell via a dichroic mirror. The atomic gas cell encapsulates gaseous alkali metal atoms, enabling omnidirectional reception of spatial microwave fields. The first laser, the atomic gas cell dichroic mirror, and the photodetector are on the same axis. The output of the atomic gas cell is connected to the input of the photodetector. The output of the photodetector is connected to the input of the host computer. The output of the host computer is connected to the inputs of the first laser, the second laser, and the first signal source.

[0032] The host computer controls the first signal source to generate periodic π-pulse microwaves, which are transmitted to the atomic gas chamber through the first antenna. This prepares the atoms in the atomic gas chamber to a specific ground state, achieving atomic initial state polarization. In a specific embodiment, the atomic gas chamber is filled with... 87 Rb atoms, with a first signal source frequency of 6.835 GHz, will have a ground state of 5S 1 / 2 The atom at F=1 transitions to the ground state 5S 1 / 2 At the F=2 fine level, atomic initial-state polarization is achieved. The first antenna is a standard horn antenna.

[0033] Atoms in a specific ground state are pumped to a Rydberg state using a laser, increasing the effective number of atoms interacting with microwaves. The first laser, atomic gas chamber, dichroic mirror, and photodetector are coaxial. The probe light generated by the first laser resonates with the transitions between the atomic ground state and metastable energy levels, while the coupling light generated by the second laser resonates with the transitions between the atomic excited state and Rydberg energy levels. The probe light and coupling light propagate in opposite directions and coincide within the atomic gas chamber, exciting the atoms to the Rydberg state. In a specific embodiment, the probe light resonates with the 5S ground state of rubidium atoms. 1 / 2 F=2 fine level and metastable 5P 3 / 2 F'=3 fine level transition resonance, coupled light and metastable 5P 3 / 2 F' = 3 fine level and Rydberg state 87D 5 / 2 Leap resonance.

[0034] The microwave field generated by the second signal source is emitted into the atomic gas cell via the second antenna. Together with the microwave field under test, it causes periodic changes in the atomic energy levels, resulting in periodic modulation of the probe light intensity. The power of the modulation signal is proportional to the power of the microwave under test, thus enabling the reception and measurement of the microwave under test. In a specific embodiment, the microwave under test and the Deburg 87D state... 5 / 2 and 86P 3 / 2 Transition resonance. The second antenna is a standard horn antenna.

[0035] The probe light and the coupling light are both linearly polarized and have the same polarization direction.

[0036] The first laser, the atomic gas chamber dichroic mirror, and the photodetector are on the same axis. The dichroic mirror transmits the probe light and reflects the coupling light.

[0037] The microwave field generated by the second signal source, together with the microwave field to be measured, causes periodic changes in the atomic energy levels, thereby producing periodic modulation in the intensity of the probe light.

[0038] The host computer controls the timing of the first signal source, the first laser, and the second laser to achieve periodic atomic polarization and microwave detection.

[0039] like Figure 2As shown, based on the above system, this invention also proposes a highly sensitive microwave receiving method with enhanced atomic polarization, comprising the following steps:

[0040] Step 1: The host computer controls the frequency and waveform of the microwave field generated by the first signal source to generate π pulses;

[0041] Step 2: Adjust the probe light generated by the first laser to resonate with the transition between the ground state and metastable state energy levels of the atom, and adjust the coupling light generated by the second laser to resonate with the transition between the excited state and Rydberg state energy levels of the atom. The probe light and the coupling light propagate in opposite directions and coincide in the atomic gas chamber, exciting the atom to the Rydberg state.

[0042] Step 3: The local oscillator microwave field generated by the second signal source and the microwave field to be measured together cause periodic changes in the atomic energy level, thereby generating periodic modulation in the intensity of the probe light;

[0043] Step 4: Use a photodetector to measure the laser emitted from the atomic gas chamber, convert the light intensity into a voltage signal, and then provide it to the host computer;

[0044] Step 5: The power of the probe optical modulation signal is proportional to the power of the microwave under test. The power of the microwave under test is calculated by the host computer to complete a single reception measurement.

[0045] Then return to step one to perform the next receiving measurement.

[0046] In this invention, a host computer controls a first signal source to generate a pulsed microwave field that prepares the atomic initial state onto a specific ground state, achieving atomic polarization. A probe light generated by a first laser resonates with the transitions of the atomic ground state and metastable energy levels, while a coupling light generated by a second laser resonates with the transitions of the atomic excited state and Rydberg state energy levels. The probe light and coupling light propagate in opposite directions and coincide within the atomic gas chamber, exciting the atom to the Rydberg state. The microwave field generated by the second signal source, together with the microwave field to be measured, causes periodic changes in the atomic energy levels, thereby generating periodic modulation of the probe light intensity. The power of the modulation signal is proportional to the power of the microwave to be measured, thus achieving the receiving and measurement of the microwave to be measured. Using the atomic polarization enhancement method of this invention, the number of atoms participating in microwave measurement can be increased, improving microwave receiving performance.

[0047] The embodiments described above are merely preferred embodiments of the present invention. Ordinary variations and substitutions made by those skilled in the art within the scope of the technical solutions of the present invention should be included within the protection scope of the present invention.

[0048] The contents not described in detail in this invention are well-known to those skilled in the art.

Claims

1. An atomic polarization enhanced high sensitivity microwave receiving system characterized by: The first laser, the atomic cell, the second laser, the dichroic mirror, the photodetector, the first signal source, the second signal source, the first antenna, the second antenna and the host computer are included. The first signal source generates periodic pi pulses under the control of the host computer, the periodic pi pulses are transmitted to the atomic cell through the first antenna, and the atoms in the atomic cell are prepared to a specific ground state to realize atomic initial state polarization. The first laser generates detection light resonant with the atomic ground state and metastable state energy level transition under the control of the host computer, and the detection light is incident to the atomic cell. The second laser generates coupling light resonant with the atomic excited state and Rydberg state energy level transition under the control of the host computer, and the coupling light enters the atomic cell after being reflected by the dichroic mirror. The second signal source generates a local microwave field, which is transmitted to the atomic cell through the second antenna, and the local microwave field and the microwave field to be measured jointly cause the periodic change of the atomic energy level, thereby generating periodic modulation on the detection light intensity. The photodetector measures the detection light intensity emitted from the atomic cell and converts the light intensity into an electrical signal, which is provided to the host computer, and the power of the detection light modulation signal is proportional to the microwave power to be measured, thereby realizing the measurement of the microwave receiving.

2. An atomic polarization enhanced high sensitivity microwave receiving system as claimed in claim 1, characterized in that: The atomic cell encapsulates gaseous alkali metal atoms, which can realize omnidirectional spatial microwave field receiving.

3. An atomic polarization enhanced high sensitivity microwave receiving system as claimed in claim 1, characterized in that: The output end of the first laser is connected with the atomic cell, and the coupling light generated by the second laser is connected with the atomic cell through the dichroic mirror; the first laser, the atomic cell, the dichroic mirror and the photodetector are on the same axis; the output end of the atomic cell is connected with the input end of the photodetector. The output end of the photodetector is connected with the input end of the host computer; the output end of the host computer is connected with the input ends of the first laser, the second laser and the first signal source.

4. An atomic polarization enhanced high sensitivity microwave receiving system as claimed in claim 1, characterized in that: The dichroic mirror transmits the detection light and reflects the coupling light.

5. An atomic polarization enhanced high sensitivity microwave receiving system as claimed in claim 1, characterized in that: The host computer controls the timing of the first signal source, the first laser and the second laser to realize periodic atomic polarization and microwave detection.

6. An atomic polarization enhanced high sensitivity microwave receiving system as claimed in claim 1, characterized in that: The detection light and the coupling light are linearly polarized light with the same polarization direction.

7. A method of atomic polarization enhanced high sensitivity microwave reception, characterized by, The host computer controls the frequency and waveform of the microwave field generated by the first signal source to generate a pi pulse; the pi pulse is transmitted to the atomic cell through the first antenna, and the atoms in the atomic cell are prepared to a specific ground state to realize atomic initial state polarization; The atoms in the specific ground state are pumped to the Rydberg state by laser to increase the effective number of atoms interacting with the microwave; The host computer controls the first laser to generate detection light resonant with the atomic ground state and metastable state energy level transition, and controls the second laser to generate coupling light resonant with the atomic excited state and Rydberg state energy level transition; the detection light and the coupling light are transmitted in opposite directions and coincide in the atomic cell to excite the atoms to the Rydberg state; The second signal source generates a local microwave field, which is transmitted to the atomic cell through the second antenna, and the local microwave field and the microwave field to be measured jointly cause the periodic change of the atomic energy level in the atomic cell, thereby generating periodic modulation on the detection light intensity to obtain a detection light modulation signal; The photodetector measures the detection light modulation signal emitted from the atomic cell, converts the light intensity into a voltage value and provides the voltage value to the host computer; The host computer calculates the microwave power to be measured to complete a single receiving measurement. The power of the detection light modulation signal is proportional to the microwave power to be measured.

8. A method of atomic polarization enhanced high sensitivity microwave reception according to claim 7, characterized in that, ​

Images