Three-light atom spectral line frequency locking system for rubidium atom Rydberg microwave electric field meter

Abstract

The invention discloses a three-light atom spectral line frequency locking system for a rubidium atom Rydberg microwave electric field meter, and the system comprises a 780nm laser, a 1260nm laser, a 776nm laser, a saturated absorption spectrum detection system, an EIT detection system, an EIA detection system, a saturated absorption spectrum frequency locking system, an EIT frequency locking system, and an EIA frequency locking system. A three-photon excitation scheme is adopted to replace a traditional two-photon excitation scheme, the size of the used laser is greatly reduced, and the output laser frequency and power are stable; compared with the existing PDH frequency locking method or laser self-operation frequency locking method, the frequency locking method combining the SAS spectrum, the EIT spectrum and the EIA spectrum has the advantages that the laser frequency locking time is greatly prolonged; the atomic spectral line three-light modulation method with the unified common modulation frequency is adopted, the frequency locking complexity of the three-light Rydberg system is fully reduced, and the method has higher popularization practicability.

Description

Technical Field

[0001] The present invention relates to the fields of Rydberg atom excitation technology, frequency locking technology and microwave electric field meter, in particular to a three-light atomic spectrum line frequency locking system for a rubidium atom Rydberg microwave electric field meter. Background Art

[0002] Rydberg atoms are excited atoms with a high principal quantum number (n ≥ 15). Due to their large atomic radius and large dipole moment, microwave detection technology based on Rydberg atoms offers outstanding advantages, including an ultra-wide detection spectrum, high sensitivity, and high detection accuracy. Improving the signal-to-noise ratio and detection accuracy of Rydberg atom microwave detection technology, expanding the diversity of Rydberg atom excitation schemes, enhancing the integration of Rydberg atom microwave detection solutions, and broadening the application scenarios of Rydberg atom microwave detection technology are key areas of focus in the microwave detection field.

[0003] The Sanguang Rydberg atomic microwave electric field meter can achieve high-precision measurement of microwave electric fields. Its measurement accuracy can approach or even exceed the standard quantum limit, providing a precise measurement method for the field of quantum metrology, helping to establish more accurate microwave electric field measurement standards and achieve traceable measurement of microwave electric fields. It has important application value in the military and communications fields.

[0004] Current Rydberg atom excitation schemes primarily employ dual-light excitation, using a long-wavelength red light beam as the probe and a short-wavelength blue light beam as the coupling excitation beam. All of these schemes require the laser to be frequency-locked. Current approaches primarily use atomic saturation spectrum frequency locking for the first excitation light. However, there are no effective methods for highly excited lasers, or alternatively, supercavity locking is employed. These methods are primarily used in scientific research experimental platforms.

[0005] The short-wave lasers used in early dual-light Rydberg atom excitation schemes have disadvantages such as being expensive, bulky, and unable to maintain long-term stability in output laser frequency and power.

[0006] The three-beam Rydberg atom excitation scheme requires precise frequency locking of the three beams. Currently, the most common method for locking the detection beam frequency in scientific research is SAS spectroscopy (Saturated Absorption Spectroscopy). Locking the coupling beam and the modified beam frequencies often uses the Pound-Drever-Hall (PDH) method, or using a laser to free-run and temporarily stabilize at a specific frequency. This method is only suitable for short-term scientific research and does not meet the long-term operational requirements of electric field meters currently used in industry. Summary of the Invention

[0007] The purpose of the present invention is to address the defects of the current three-light Rydberg electric field meter device frequency locking scheme and provide a three-light atomic spectral line frequency locking system for rubidium atom Rydberg microwave electric field meter.

[0008] The present invention achieves the above-mentioned purpose through the following technical means:

[0009] A three-light atomic spectrum line frequency locking system for a rubidium atom Rydberg microwave electric field meter, comprising a 780nm laser, a 1260nm laser, a 776nm laser, an EIA detection system, and an EIA frequency locking system, wherein the 780nm laser beam output by the 780nm laser is split into a first 780nm laser beam, a third 780nm laser beam, and a fourth 780nm laser beam, and the 776nm laser beam is split into a first 776nm laser beam and a second 776nm laser beam;

[0010] The 1260nm laser output by the 1260nm laser, the 1260nm laser, the second 776nm laser, and the fourth 780nm laser are input into the EIA detection system. The EIA detection system outputs the 780nm laser carrying the Rydberg state three-light EIA spectrum signal of the rubidium atom. The EIA frequency locking system coherently demodulates the 780nm laser carrying the Rydberg state three-light EIA spectrum signal of the rubidium atom, and outputs a third error signal to the PID controller of the 1260nm laser. The PID controller of the 1260nm laser locks the laser frequency output by the 1260nm laser to the Rydberg state three-light EIA spectrum of the rubidium atom based on the third error signal.

[0011] As described above, the EIA detection system includes a third half-wave plate, a fourth half-wave plate, a third polarization beam splitter, a third rubidium atomic gas cell, a fourth polarization beam splitter, a second reflector, and a first photoelectric probe;

[0012] The second 776nm laser passes through the fourth half-wave plate and the fourth polarization beam splitter in sequence and then enters the third rubidium atomic gas chamber;

[0013] The fourth 780nm laser passes through the third half-wave plate and the third polarization beam splitter in sequence and then enters the third rubidium atomic gas chamber;

[0014] The 1260nm laser output by the 1260nm laser passes through the second reflector and the third polarization beam splitter in sequence and then enters the third rubidium atomic gas chamber;

[0015] The 1260nm laser, the second 776nm laser, and the fourth 780nm laser are input into the third rubidium atomic gas chamber to obtain a seventh 780nm laser. The seventh 780nm laser is a 780nm laser carrying the Rydberg state three-light EIA spectrum signal of the rubidium atom. The seventh 780nm laser passes through the fourth polarization beam splitter and is input into the first photoelectric probe. The first photoelectric probe detects the seventh 780nm laser and converts it into a third electrical signal.

[0016] As described above, the EIA frequency locking system includes a signal generator and a first mixer. The signal generator outputs a sinusoidal signal to the first mixer. The first photoelectric probe outputs a third electrical signal to the first mixer. The sinusoidal signal and the third electrical signal are mixed by the first mixer to obtain a third error signal.

[0017] It also includes a saturated absorption spectrum detection system and a saturated absorption spectrum frequency locking system. A first 780nm laser is input into the saturated absorption spectrum detection system. The saturated absorption spectrum detection system outputs a 780nm laser carrying the D1 line saturated absorption spectrum signal of the rubidium atoms. The saturated absorption spectrum frequency locking system coherently demodulates the 780nm laser carrying the D1 line saturated absorption spectrum signal of the rubidium atoms, and outputs a first error signal to the PID controller of the 780nm laser. The PID controller of the 780nm laser locks the laser frequency output by the 780nm laser to the D1 line saturated absorption spectrum of the rubidium atoms according to the first error signal.

[0018] As described above, the saturation absorption spectrum detection system includes an electro-optical modulator, a first beam splitter, a first half-wave plate, a first polarization beam splitter, a first rubidium atomic gas chamber, a quarter-wave plate, a first reflector, and a second photoelectric probe. The 780nm laser output by the 780nm laser is modulated by the electro-optical modulator to output 780nm modulated light. The 780nm modulated light is then split into a first 780nm laser and a second 780nm laser by the first beam splitter. The first 780nm laser passes through the first half-wave plate, the first polarization beam splitter, the first rubidium atomic gas chamber, the quarter-wave plate, and the first reflector in sequence. After being reflected by the first reflector, it passes through the quarter-wave plate and the first rubidium atomic gas chamber in sequence to obtain a fifth 780nm laser. The fifth 780nm laser is a 780nm laser carrying a D1 line saturation absorption spectrum signal. The fifth 780nm laser passes through the first polarization beam splitter and is input into the second photoelectric probe. The second photoelectric probe detects the fifth 780nm laser and converts it into a first electrical signal.

[0019] As described above, the saturated absorption spectrum frequency locking system includes a signal generator and a second mixer. The signal generator outputs a sinusoidal signal to the second mixer. The second photoelectric probe outputs a first electrical signal to the second mixer. The sinusoidal signal and the first electrical signal are mixed by the second mixer to obtain a first error signal.

[0020] The system also includes an EIT detection system and an EIA frequency locking system. The first 776nm laser and the third 780nm laser are input into the EIT detection system. The EIT detection system outputs a 780nm laser carrying a 5D-state two-light EIT spectrum signal of rubidium atoms. The EIT frequency locking system coherently demodulates the 780nm laser carrying the 5D-state two-light EIT spectrum signal of rubidium atoms, and outputs a second error signal to a PID controller of the 776nm laser. The PID controller of the 776nm laser locks the laser frequency output by the 776nm laser to the 5D-state two-light EIT spectrum of the rubidium atoms based on the second error signal.

[0021] As described above, the EIT detection system includes a third beam splitter, a second polarization beam splitter, a second half-wave plate, a second rubidium atomic gas cell, and a second beam splitter;

[0022] The 776nm laser output by the 776nm laser is split into a first 776nm laser and a second 776nm laser by a third beam splitter. The first 776nm laser is sequentially input into the second rubidium atomic gas chamber through a second polarization beam splitter and a second half-wave plate.

[0023] The second 780nm laser is split into a third 780nm laser and a fourth 780nm laser by a second beam splitter, and the third 780nm laser is input into the second rubidium atomic gas chamber;

[0024] The first 776nm laser and the third 780nm laser are input into the second rubidium atomic gas chamber to obtain a sixth 780nm laser. The sixth 780nm laser is a 780nm laser carrying the 5D state two-light EIT spectrum signal of the rubidium atom. The sixth 780nm laser passes through the second half-wave plate and the second polarization beam splitter in sequence and is input into the third photoelectric probe. The third photoelectric probe detects the sixth 780nm laser and converts it into a second electrical signal.

[0025] As described above, the EIT frequency locking system includes a signal generator and a third mixer. The signal generator outputs a sinusoidal signal to the third mixer. The third photoelectric probe outputs a second electrical signal to the third mixer. The sinusoidal signal and the second electrical signal are mixed by the third mixer to obtain a second error signal.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) The present invention adopts a three-photon excitation scheme to replace the traditional two-photon excitation scheme, which greatly reduces the volume of the laser used and makes the output laser frequency and power stable and controllable.

[0028] (2) The present invention adopts a frequency locking method that combines SAS spectrum with EIT spectrum and EIA spectrum, which greatly improves the laser frequency locking time compared with the current PDH frequency locking method or laser self-operation frequency locking method.

[0029] (3) The present invention adopts a three-light modulation method of atomic spectral lines with a unified common modulation frequency, which fully reduces the frequency locking complexity of the three-light Rydberg system, making the method of the present invention more popularizable and practical.

[0030] In summary, based on the many characteristics of Rydberg atoms and laboratory results, the present invention proposes and implements a method for long-term locking of three optical frequencies of atomic spectral lines using a unified common modulation frequency. This method has long-term stable operation, is easy to use, can be mass-produced, and can be widely used in important fields such as weak microwave field detection and communication. It makes up for the shortcomings of the original solution, such as large device size, unstable laser power, and inability to lock frequency and operate for a long time. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a structural schematic diagram of the system of the present invention;

[0032] Reference numerals and corresponding component names:

[0033] 1-1260nm laser; 2-780nm laser; 3-776nm laser; 4-first beam splitter; 5-second beam splitter; 6-third beam splitter; 7-first half-wave plate; 8-second half-wave plate; 9-third half-wave plate; 10-fourth half-wave plate; 11-first polarization beam splitter; 12-second polarization beam splitter; 13-third polarization beam splitter; 14-fourth polarization beam splitter; 15-first rubidium atomic gas chamber; 16-second rubidium atomic gas chamber; 17-third rubidium atomic gas chamber; 18-quarter wave plate; 19-first reflector; 20-second reflector; 21-first photoelectric probe; 22-second photoelectric probe; 23-third photoelectric probe; 24-first mixer; 25-second mixer; 26-third mixer; 27-signal generator; 28-electro-optical modulator. Specific implementation plan

[0034] In order to facilitate those skilled in the art to understand and implement the present invention, the present invention is further described in detail below in conjunction with embodiments. It should be understood that the embodiments described herein are only used to illustrate and explain the present invention and are not used to limit the present invention.

[0035] Example 1:

[0036] like Figure 1As shown, a three-light atomic spectrum line frequency locking system for a rubidium atom Rydberg microwave electric field meter includes a 780nm laser 2, a 1260nm laser 1, a 776nm laser 3, a saturated absorption spectrum detection system, an EIT detection system, an EIA detection system, a saturated absorption spectrum frequency locking system, an EIT frequency locking system, and an EIA frequency locking system;

[0037] The 780nm laser beam output by the 780nm laser 2 is split into a first 780nm laser beam, a third 780nm laser beam, and a fourth 780nm laser beam. The first 780nm laser beam is input into a saturated absorption spectrum detection system. The saturated absorption spectrum detection system outputs a 780nm laser beam carrying a D1 line saturated absorption spectrum signal of rubidium atoms. The saturated absorption spectrum frequency locking system coherently demodulates the 780nm laser beam carrying the D1 line saturated absorption spectrum signal of rubidium atoms and outputs a first error signal to a PID controller of the 780nm laser 2. The PID controller of the 780nm laser 2 locks the laser frequency output by the 780nm laser 2 to the D1 line saturated absorption spectrum of the rubidium atoms according to the first error signal.

[0038] The split beam output by the 776nm laser 3 is a first 776nm laser and a second 776nm laser. The first 776nm laser and the third 780nm laser are input into the EIT detection system. The EIT detection system outputs a 780nm laser that carries the 5D-state two-light EIT spectrum signal of the rubidium atoms. The EIT frequency locking system coherently demodulates the 780nm laser that carries the 5D-state two-light EIT spectrum signal of the rubidium atoms and outputs a second error signal to the PID controller of the 776nm laser 3. The PID controller of the 776nm laser 3 locks the laser frequency output by the 776nm laser 3 to the 5D-state two-light EIT spectrum of the rubidium atoms based on the second error signal.

[0039] The 1260nm laser light output by the 1260nm laser 1, the 1260nm laser light, the second 776nm laser light, and the fourth 780nm laser light are input into the EIA detection system. The EIA detection system outputs the 780nm laser light carrying the Rydberg state three-light EIA spectrum signal of the rubidium atom. The EIA frequency locking system coherently demodulates the 780nm laser light carrying the Rydberg state three-light EIA spectrum signal of the rubidium atom, and outputs a third error signal to the PID controller of the 1260nm laser 1. The PID controller of the 1260nm laser 1 locks the frequency of the laser light output by the 1260nm laser 1 to the Rydberg state three-light EIA spectrum of the rubidium atom based on the third error signal.

[0040] The saturation absorption spectrum detection system includes an electro-optical modulator 28, a first beam splitter 4, a first half-wave plate 7, a first polarization beam splitter 11, a first rubidium atomic gas chamber 15, a quarter-wave plate 18, a first reflector 19, and a second photoelectric probe 22. The 780nm laser output by the 780nm laser 2 is modulated by the electro-optical modulator 28 and outputs 780nm modulated light. The 780nm modulated light is then split by the first beam splitter 4 into a first 780nm laser (the laser emitted by the first beam splitter 4 has a propagation direction that is 90° different from the original propagation direction) and a second 780nm laser (the laser transmitted through the first beam splitter 4 and reflected and propagated along the original propagation direction). The first 780nm laser is input to the first half-wave plate 7. The first The 780nm laser light is converted into first polarized light (having a phase difference of one-half relative to the first 780nm laser light) by the first half-wave plate 7. The first polarized light is transmitted through the first polarization beam splitter 11, the first rubidium atomic gas cell 15, and the quarter-wave plate 18. After being reflected by the first reflector 19, it passes through the quarter-wave plate 18 and the first rubidium atomic gas cell 15 again in sequence to obtain a 780nm laser light carrying a D1 line saturated absorption spectrum signal, which is recorded as the fifth 780nm laser light (at this time, the phase difference relative to the first 780nm laser light changes from one-half to one). The fifth 780nm laser light is reflected by the first polarization beam splitter 11 and enters the second photoelectric probe 22. The second photoelectric probe 22 detects the fifth 780nm laser light and converts it into a first electrical signal.

[0041] As an implementable embodiment, the 780nm laser 2 outputs 780nm laser light to the electro-optical modulator 28, the electro-optical modulator 28 outputs 780nm modulated light, the first beam splitter 4 is placed on the same vertical axis as the electro-optical modulator 28, the incident surface of the first beam splitter 4 faces the 780nm modulated light output by the electro-optical modulator 28, and the adjacent side surface of the incident surface of the first beam splitter 4 faces the first half-wave plate 7. The first half-wave plate 7, the first polarization beam splitter 11, the first rubidium atomic gas chamber 15, the quarter-wave plate 18, and the first reflector 19 are placed in sequence on the same horizontal axis, and the optical axes of the quarter-wave plate 18 and the first reflector 19 coincide with the first half-wave plate 7.

[0042] The EIT detection system includes a third beam splitter 6, a second polarization beam splitter 12, a second half-wave plate 8, a second rubidium atomic gas cell 16, and a second beam splitter 5;

[0043] The 776nm laser light output by the 776nm laser 3 is split by the third beam splitter 6 into a first 776nm laser light (the laser light reflected by the third beam splitter 6 has its propagation direction shifted 90° from the original propagation direction) and a second 776nm laser light (the laser light reflected by the third beam splitter 6 is propagated along the original propagation direction). The first 776nm laser light is transmitted through the second polarization beam splitter 12 and the second half-wave plate 8 and enters the second rubidium atomic gas chamber 16.

[0044] The second 780nm laser is input to the second beam splitter 5, which splits the laser into a third 780nm laser (the laser reflected by the second beam splitter 5 has its propagation direction shifted by 90° relative to the original propagation direction) and a fourth 780nm laser (the laser reflected by the second beam splitter 5 propagates along the original propagation direction). The third 780nm laser is input to the second rubidium atomic gas cell 16.

[0045] The first 776nm laser and the third 780nm laser are input into the second rubidium atomic gas chamber 16. The 780nm modulated light and the 776nm laser interact with the atoms in the second rubidium atomic gas chamber 16, generating an EIT phenomenon. A 780nm laser carrying a 5D-state two-light EIT spectrum signal of the rubidium atoms is obtained, which is recorded as the sixth 780nm laser. The sixth 780nm laser passes through the second half-wave plate 8 and the second polarization beam splitter 12 in sequence, and is reflected by the second polarization beam splitter 12 to the third photoelectric probe 23. The third photoelectric probe 23 detects the sixth 780nm laser and converts it into a second electrical signal.

[0046] The second half-wave plate 8 and the second polarization beam splitter 12 are used to change the phases of the first 776nm laser, the third 780nm laser, and the sixth 780nm laser to prevent the first 776nm light from being mistakenly detected by the third photoelectric probe 23 and ensure that the sixth 780nm laser is accurately detected.

[0047] As an implementable embodiment, the second beam splitter 5 is placed on the same vertical axis as the first beam splitter 4, the incident surface of the second beam splitter 5 is opposite to the transmitted light output surface of the first beam splitter 4, the second beam splitter 5, the second rubidium atomic gas chamber 16, the second half-wave plate 8, the second polarization beam splitter 12, and the third beam splitter 6 are placed on the same horizontal axis, the optical axis of the second half-wave plate 8 and the transmitted light axis of the second polarization beam splitter 12 both coincide with the reflected light axis of the second beam splitter 5, and the reflected light of the second polarization beam splitter 12 is opposite to the third photoelectric probe 23.

[0048] The EIA detection system includes a third half-wave plate 9, a fourth half-wave plate 10, a third polarization beam splitter 13, a third rubidium atom gas cell 17, a fourth polarization beam splitter 14, a second reflector 20, and a first photoelectric probe 21;

[0049] The second 776 nm laser light passes through the fourth half wave plate 10 and the fourth polarization beam splitter 14 in sequence, and is reflected by the fourth polarization beam splitter 14 into the third rubidium atomic gas chamber 17;

[0050] The fourth 780nm laser passes through the third half-wave plate 9 and the third polarization beam splitter 13 in sequence;

[0051] The 1260nm laser output by the 1260nm laser 1 is reflected by the second reflector 20 and enters the third polarization beam splitter 13. The combined light is combined with the fourth 780nm laser entering the third polarization beam splitter 13 and enters the third rubidium atomic gas chamber 17.

[0052] The combined light and the second 776nm laser light enter the third rubidium atomic gas chamber 17 and interact with the atoms to obtain a 780nm laser light carrying the Rydberg state three-light EIA spectrum signal of the rubidium atoms, which is recorded as the seventh 780nm laser light. The seventh 780nm laser light is transmitted through the fourth polarization beam splitter 14 and enters the first photoelectric probe 21. The first photoelectric probe 21 detects the seventh 780nm laser light and converts it into a third electrical signal.

[0053] As an embodiment, the third beam splitter 6 is placed on the same horizontal axis as the second beam splitter 5, with the incident surface of the third beam splitter 6 facing the transmitted light exit surface of the second beam splitter 5. The second reflector 20, the third polarization beam splitter 13, the fourth polarization beam splitter 14, and the third rubidium atomic gas chamber 17 are placed on the same horizontal axis. The third half-wave plate 9 is placed between the second beam splitter 5 and the third polarization beam splitter 13, with the incident surface of the wave plate facing the transmitted light of the second beam splitter 5. The fourth half-wave plate 10 is placed between the third beam splitter 6 and the fourth polarization beam splitter 14, with the incident surface of the wave plate facing the transmitted light of the third beam splitter 6. The normal direction of the second reflector 20 is at an angle of 45° to the output direction of the 1260nm laser 1. The normal direction of the second reflector 20 is perpendicular to the splitting direction of the third polarization beam splitter 13 and parallel to the splitting direction of the fourth polarization beam splitter 14. The laser incident surface and laser output surface of the horizontally placed third rubidium atomic gas cell 17 are respectively opposite to the incident surface of the third polarization beam splitter 13 and the incident surface of the fourth polarization beam splitter 14. The transmitted light of the fourth polarization beam splitter 14 is opposite to the first photoelectric probe 21.

[0054] The saturated absorption spectrum frequency locking system includes a signal generator 27 and a second mixer 25. The signal generator 27 outputs a sinusoidal signal to the second mixer 25. Two input ends of the second mixer 25 are connected to the output end of the signal generator 27 and the output end of the second photoelectric probe 22. The second photoelectric probe 22 outputs a first electrical signal to the second mixer 25. The sinusoidal signal and the first electrical signal are mixed (multiplied) by the second mixer 25, that is, coherent demodulation is performed to obtain a first error signal (that is, a dispersion-shaped signal with a center of 0 and signals on both sides of the center showing positive and negative linear changes, respectively, reflecting the degree of deviation of the 780nm laser). The PID controller of the 780nm laser 2 adjusts the driver of the 780nm laser 2 according to the first error signal to pull the laser frequency output by the 780nm laser 2 back to the locking point, thereby locking the laser frequency output by the 780nm laser 2 to the D1 line saturated absorption spectrum of the rubidium atom.

[0055] The EIT frequency locking system includes a signal generator 27 and a third mixer 26. The signal generator 27 outputs a sinusoidal signal to the third mixer 26. Two input ends of the third mixer 26 are connected to the output end of the signal generator 27 and the output end of the third photoelectric probe 23. The third photoelectric probe 23 outputs a second electrical signal to the third mixer 26. The sinusoidal signal and the second electrical signal are mixed (multiplied) by the third mixer 26, that is, coherently demodulated to obtain a second error signal (reflecting the degree of deviation of the 776nm laser). The PID controller of the 776nm laser 3 adjusts the driver of the 776nm laser 3 according to the second error signal to pull the laser frequency output by the 776nm laser 3 back to the locking point, thereby locking the laser frequency output by the 776nm laser 3 to the 5D state two-light EIT spectrum of the rubidium atom.

[0056] The EIA frequency locking system includes a signal generator 27 and a first mixer 24. The signal generator 27 outputs a sinusoidal signal to the first mixer 24. The two input ends of the first mixer 24 are connected to the output end of the signal generator 27 and the output end of the first photoelectric probe 21. The first photoelectric probe 21 outputs a third electrical signal to the first mixer 24. The sinusoidal signal and the third electrical signal are mixed (multiplied) by the first mixer 24, that is, coherently demodulated to obtain a third error signal (reflecting the degree of deviation of the 1260nm laser). The PID controller of the 1260nm laser 1 adjusts the driver of the 1260nm laser 1 according to the third error signal to pull the laser frequency output by the 1260nm laser 1 back to the locking point, thereby locking the laser frequency output by the 1260nm laser 1 to the Rydberg state three-light EIA spectrum of the rubidium atom.

[0057] The specific examples described herein are merely illustrative of the spirit of the present invention. Persons skilled in the art may make various modifications, additions, or substitutions to the described specific examples without departing from the spirit of the present invention or exceeding the scope of the appended claims.

Claims

1. A three-light atomic spectrum line frequency locking system for a rubidium atom Rydberg microwave electric field meter, comprising a 780 nm laser (2), characterized in that: The system also includes a 1260 nm laser (1), a 776 nm laser (3), an EIA detection system, and an EIA frequency locking system. The 780 nm laser beam output by the 780 nm laser (2) is split into a first 780 nm laser beam, a third 780 nm laser beam, and a fourth 780 nm laser beam. The 776 nm laser (3) outputs a split beam into a first 776 nm laser beam and a second 776 nm laser beam. The 1260nm laser output by the 1260nm laser (1), the 1260nm laser, the second 776nm laser, and the fourth 780nm laser are input into the EIA detection system. The EIA detection system outputs the 780nm laser carrying the Rydberg state three-light EIA spectrum signal of the rubidium atom. The EIA frequency locking system coherently demodulates the 780nm laser carrying the Rydberg state three-light EIA spectrum signal of the rubidium atom and outputs a third error signal to the PID controller of the 1260nm laser (1). The PID controller of the 1260nm laser (1) locks the laser frequency output by the 1260nm laser (1) to the Rydberg state three-light EIA spectrum of the rubidium atom according to the third error signal.

2. The three-light atomic spectral line frequency locking system for a rubidium atom Rydberg microwave electric field meter according to claim 1, characterized in that: The EIA detection system includes a third half-wave plate (9), a fourth half-wave plate (10), a third polarization beam splitter (13), a third rubidium atomic gas chamber (17), a fourth polarization beam splitter (14), a second reflector (20), and a first photoelectric probe (21); The second 776nm laser passes through the fourth half-wave plate (10) and the fourth polarization beam splitter (14) in sequence and then enters the third rubidium atomic gas chamber (17); The fourth 780nm laser passes through the third half-wave plate (9) and the third polarization beam splitter (13) in sequence and then enters the third rubidium atomic gas chamber (17); The 1260nm laser light outputted by the 1260nm laser (1) passes through the second reflector (20) and the third polarization beam splitter (13) in sequence and then enters the third rubidium atomic gas chamber (17); The 1260nm laser, the second 776nm laser, and the fourth 780nm laser are input into the third rubidium atom gas chamber (17) to obtain a seventh 780nm laser. The seventh 780nm laser is a 780nm laser that carries the Rydberg state three-light EIA spectrum signal of the rubidium atom. The seventh 780nm laser passes through the fourth polarization beam splitter (14) and is input into the first photoelectric probe (21). The first photoelectric probe (21) detects the seventh 780nm laser and converts it into a third electrical signal.

3. The three-light atomic spectral line frequency locking system for the rubidium atom Rydberg microwave electric field meter according to claim 2, characterized in that: The EIA frequency locking system includes a signal generator (27) and a first mixer (24), wherein the signal generator (27) outputs a sinusoidal signal to the first mixer (24), and the first photoelectric probe (21) outputs a third electrical signal to the first mixer (24), and the sinusoidal signal and the third electrical signal are mixed by the first mixer (24) to obtain a third error signal.

4. The three-light atomic spectral line frequency locking system for a rubidium atom Rydberg microwave electric field meter according to claim 1, characterized in that: The invention also includes a saturated absorption spectrum detection system and a saturated absorption spectrum frequency locking system. A first 780nm laser is input into the saturated absorption spectrum detection system. The saturated absorption spectrum detection system outputs a 780nm laser carrying a D1 line saturated absorption spectrum signal of rubidium atoms. The saturated absorption spectrum frequency locking system performs coherent demodulation on the 780nm laser carrying the D1 line saturated absorption spectrum signal of rubidium atoms and outputs a first error signal to a PID controller of the 780nm laser (2). The PID controller of the 780nm laser (2) locks the laser frequency output by the 780nm laser (2) to the D1 line saturated absorption spectrum of the rubidium atoms according to the first error signal.

5. The three-light atomic spectral line frequency locking system for a rubidium atom Rydberg microwave electric field meter according to claim 4, characterized in that: The saturation absorption spectrum detection system includes an electro-optical modulator (28), a first beam splitter (4), a first half-wave plate (7), a first polarization beam splitter (11), a first rubidium atomic gas chamber (15), a quarter-wave plate (18), a first reflector (19), and a second photoelectric probe (22). The 780nm laser output by the 780nm laser (2) is modulated by the electro-optical modulator (28) and outputs 780nm modulated light. The 780nm modulated light is then split into a first 780nm laser and a second 780nm laser by the first beam splitter (4). The first 780nm laser is sequentially split into the first and second 780nm lasers. A quarter-wave plate (7), a first polarization beam splitter (11), a first rubidium atomic gas chamber (15), a quarter-wave plate (18), and a first reflector (19) are provided. After being reflected by the first reflector (19), the light passes through the quarter-wave plate (18) and the first rubidium atomic gas chamber (15) in sequence to obtain a fifth 780nm laser. The fifth 780nm laser is a 780nm laser carrying a D1 line saturation absorption spectrum signal. The fifth 780nm laser passes through the first polarization beam splitter (11) and is input into the second photoelectric probe (22). The second photoelectric probe (22) detects the fifth 780nm laser and converts it into a first electrical signal.

6. The three-light atomic spectral line frequency locking system for a rubidium atom Rydberg microwave electric field meter according to claim 5, characterized in that: The saturated absorption spectrum frequency locking system includes a signal generator (27) and a second mixer (25), wherein the signal generator (27) outputs a sinusoidal signal to the second mixer (25), and the second photoelectric probe (22) outputs a first electrical signal to the second mixer (25), and the sinusoidal signal and the first electrical signal are mixed by the second mixer (25) to obtain a first error signal.

7. The three-light atomic spectral line frequency locking system for a rubidium atom Rydberg microwave electric field meter according to claim 1, characterized in that: The invention also includes an EIT detection system and an EIA frequency locking system. The first 776nm laser and the third 780nm laser are input into the EIT detection system. The EIT detection system outputs a 780nm laser carrying a 5D-state two-light EIT spectrum signal of rubidium atoms. The EIT frequency locking system coherently demodulates the 780nm laser carrying the 5D-state two-light EIT spectrum signal of rubidium atoms and outputs a second error signal to a PID controller of the 776nm laser (3). The PID controller of the 776nm laser (3) locks the laser frequency output by the 776nm laser (3) to the 5D-state two-light EIT spectrum of the rubidium atoms according to the second error signal.

8. The three-light atomic spectral line frequency locking system for a rubidium atom Rydberg microwave electric field meter according to claim 7, characterized in that: The EIT detection system comprises a third beam splitter (6), a second polarization beam splitter (12), a second half-wave plate (8), a second rubidium atomic gas chamber (16), and a second beam splitter (5); The 776 nm laser output by the 776 nm laser (3) is split into a first 776 nm laser and a second 776 nm laser by a third beam splitter (6), and the first 776 nm laser is sequentially input into the second rubidium atomic gas chamber (16) by a second polarization beam splitter (12) and a second half-wave plate (8); The second 780nm laser is sequentially split into a third 780nm laser and a fourth 780nm laser by a second beam splitter (5), and the third 780nm laser is input into the second rubidium atomic gas chamber (16); The first 776nm laser and the third 780nm laser are input into the second rubidium atom gas chamber (16) to obtain a sixth 780nm laser. The sixth 780nm laser is a 780nm laser carrying a 5D-state two-light EIT spectrum signal of the rubidium atom. The sixth 780nm laser passes through the second half-wave plate (8) and the second polarization beam splitter (12) in sequence and is input into the third photoelectric probe (23). The third photoelectric probe (23) detects the sixth 780nm laser and converts it into a second electrical signal.

9. The three-light atomic spectral line frequency locking system for a rubidium atom Rydberg microwave electric field meter according to claim 8, characterized in that: The EIT frequency locking system includes a signal generator (27) and a third mixer (26), wherein the signal generator (27) outputs a sinusoidal signal to the third mixer (26), and the third photoelectric probe (23) outputs a second electrical signal to the third mixer (26), and the sinusoidal signal and the second electrical signal are mixed by the third mixer (26) to obtain a second error signal.

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