Device and method for measuring wavelength of atomic substance wave

Abstract

The invention discloses an atomic substance wave length measuring device, which comprises a vacuum cavity, a first split beam and a second split beam which are obtained by light splitting of test laser penetrate through the vacuum cavity in a direction parallel to the height of the vacuum cavity and are detected by a first photoelectric detector after being combined, detection laser is further irradiated in the vacuum cavity, and the first photoelectric detector is connected with a second photoelectric detector through a second photoelectric detector. The test laser is split, the first split light and the second split light are combined to obtain combined light, and the shape defined by a middle light path is a rectangle. The invention also discloses an atomic substance wave wavelength measuring method, which comprises the following steps of: adjusting test laser into slit light, and actually measuring the flight time of a measured object; and adjusting the test laser to be continuous laser, and testing the actually measured flight distance of the measured object, thereby obtaining the actually measured flight speed and the wavelength of the substance wave of the measured object. The method is not influenced by the change of the initial position of the measured object, so that the flying speed measurement of the measured object can be improved, and the method is used for accurately measuring the wavelength of the substance wave.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of quantum sensing technology, and more particularly to an atomic matter wave wavelength measuring device and an atomic matter wave wavelength measuring method. The present application is suitable for the field of atomic interference precision measurement. BACKGROUND

[0002] Atomic interferometer is a new type of measuring instrument based on quantum technology, which can be used for precise measurement of inertial quantities such as rotation, gravity and gravity gradient. Compared with traditional interferometers, atomic interferometers have the advantages of high precision, good stability and calibration due to their shorter matter wave wavelength. High-precision atomic interferometers can be used in geodesy, geological exploration and inertial navigation.

[0003] The matter wave wavelength of an atom is an important parameter of an atomic interferometer, and accurate measurement of the matter wave wavelength of an atom helps to improve the measurement accuracy of an atomic interferometer. For example, for an atomic interference gyroscope, the matter wave wavelength of an atom determines the rotation scale factor, and its measurement accuracy directly determines the measurement accuracy of the atomic interference gyroscope. For atomic interference gravimeters and atomic interference gravity gradiometers, the measurement of the matter wave wavelength of an atom can improve the accuracy of system error evaluation.

[0004] Quantum mechanics indicates that the matter wave wavelength of an atom is inversely proportional to the product of the atomic mass and the flight speed. Among them, the atomic mass can be measured to an accuracy of 10 -11 orders of magnitude by ion traps and other technical means, which can meet the current requirements of atomic interferometers for wavelength accuracy. Therefore, the measurement of the matter wave wavelength of an atom mainly focuses on the accurate measurement of the flight speed.

[0005] The existing related articles and technical solutions for the application background of the present application are as follows:

[0006] Up to now, the measurement of flight speed can be realized by measuring the Doppler frequency or by measuring the flight time. Among them, the accuracy of the Doppler frequency measurement method is related to the measurement accuracy of the frequency, which is easily affected by factors such as optical frequency shift. In the flight time method, the flight speed measurement value is highly dependent on the initial position positioning of the atomic projection, and cannot give an absolute speed measurement value. The speed measurement accuracy of the above two methods is limited, and cannot meet the demand of atomic interferometers for high-precision measurement of atomic wavelength. High-precision atomic matter wave wavelength measurement is still a major technical bottleneck that limits the improvement of the measurement accuracy of high-precision atomic interferometers. SUMMARY

[0007] To address the limited accuracy of current flight speed measurements, this invention proposes an atomic matter wave wavelength measurement device and a method for measuring atomic matter wave wavelengths. Based on flight speed measurement, this invention enables the measurement of atomic matter wave wavelengths. To achieve flight speed measurement, this invention constructs an optical Michelson interferometer to measure laser distance, and simultaneously utilizes a Ramsey-type atomic interferometer to measure the evolution time and distance of atoms passing through the two beams of light, ultimately achieving precise flight speed measurement.

[0008] The above-mentioned objective of this invention is achieved through the following technical solution:

[0009] An atomic matter wave wavelength measurement device includes a vacuum cavity of an atomic interferometer. The length direction of the vacuum cavity is taken as the x-axis, and the height direction as the y-axis. A first-frequency laser and a second-frequency laser are combined using a beam combiner as the test laser. The test laser is split to obtain a first-splitter beam and a second-splitter beam. Both the first and second-splitter beams are incident parallel to the y-axis and pass through the vacuum cavity before being combined to obtain a combined beam. The combined beam is detected by a first photodetector. A detection laser also illuminates the vacuum cavity, and the second-splitter beam, the first-splitter beam, and the detection laser are arranged sequentially along the x-axis within the vacuum cavity. A second photodetector is positioned outside the vacuum cavity at a location corresponding to the detection laser.

[0010] In this process, the optical path is rectangular, from the moment the test laser is split into a first beam and a second beam, to the moment the first beam and the second beam are combined to obtain a combined beam.

[0011] Test the measured flight time of the test object At that time, the test laser passes through the slit and is then split. The direction from which the test object is ejected to the detection in the vacuum cavity is the positive x-axis. The second beam split, the first beam split, and the detection laser sequentially perform matter wave splitting, matter wave combining, and fluorescence excitation on the flying test object.

[0012] The measured flight distance of the test object At that time, the slit was removed, and the test laser was directly split.

[0013] As described above, the test laser undergoes polarization adjustment after passing through a first half-wave plate, and then is split by a first polarizing beam splitter to obtain a first split beam and a second split beam. The first split beam passes through the first polarizing beam splitter and the second quarter-wave plate in sequence, then passes through the vacuum cavity in a direction parallel to the y-axis, and is incident on the fourth polarizing beam splitter in a direction parallel to the y-axis. Simultaneously, the second split beam is reflected by the first polarizing beam splitter, then passes through a third half-wave plate in a direction parallel to the x-axis, and after being redirected by the second polarizing beam splitter, it also passes through the first quarter-wave plate in a direction parallel to the y-axis and passes through the vacuum cavity. After being reflected by the third polarizing beam splitter, it reaches the fourth polarizing beam splitter in a direction parallel to the x-axis. At the fourth polarizing beam splitter, the first and second split beams are combined to obtain a combined beam. The combined beam passes through a second half-wave plate and a fifth polarizing beam splitter and is incident on a first photodetector, which outputs an interference signal.

[0014] As mentioned above, the analyte is an atom, molecule, or ion.

[0015] A method for measuring the wavelength of atomic matter waves, utilizing the atomic matter wave wavelength measuring device described above, includes the following steps:

[0016] Step 1: Construct a device for measuring the wavelength of atomic matter waves;

[0017] Step 2: Both the first-frequency laser and the second-frequency laser are input into the beam combiner. A slit is placed after the beam combiner. The object to be tested is launched into the vacuum cavity of the atomic interferometer in the positive x-axis direction, and the measured flight time of the object is measured. ;

[0018] Step 3: Stop launching the object to be tested, remove the slit, and use the interference signal output by the first photodetector to measure the parallel distance between the first and second beams in the vacuum cavity, thereby obtaining the measured flight distance of the object to be tested after passing through the first and second beams. ;

[0019] Step 4: Based on the measured flight distance and measured flight time Obtain the measured flight speed .

[0020] The atomic matter wave wavelength measurement method described above further includes the following steps: Step 5: Obtain the matter wave wavelength using the following formula. Precise measurement value:

[0021] ,

[0022] in The wavelength of matter waves, is Planck's constant. The mass of the object being measured.

[0023] As described above, step 2 includes the following steps:

[0024] Step 2.1: After placing the beam combiner, position the slit to adjust the test laser to slit light;

[0025] Step 2.2: Adjust the corresponding Rabi frequency by adjusting the intensity of the test laser. , making This makes the first and second beams obtained from the test laser beam splitting equivalent to π / 2 pulses. The interaction time between the object under test and the beam splitter;

[0026] Step 2.3: Detuning of Raman two-photon signals Perform linear scanning, adjusting Raman two-photon mistuning each time. Each time the object to be tested is ejected, one round of Ramsey interferometry is completed, and the fluorescence signal of the corresponding object is collected, thereby obtaining the Ramsey interference fringes;

[0027] Step 2.4: Fit the Ramsey interference fringes based on the following formula:

[0028] ,

[0029] The independent variable in the fitting is Raman two-photon detuning. , Indicating Raman two-photon detuning The corresponding fluorescence signal intensity; The amplitude of the fluorescence signal intensity. For the initial phase, The measured flight time is the free evolution time of the object under test between the two split laser beams, and is the value to be solved. Raman two-photon detuning The corresponding interference phase shift, and the fitting process in step 2.4, yields the Raman two-photon detuning. The corresponding interference phase shift;

[0030] Step 2.5: From the fitting results, take the first Raman two-photon detuning. And the corresponding interference phase shift is denoted as Take the first Raman light two-photon detuning Second Raman two-photon mistuning with different values and the corresponding interference phase shift The measured flight time of the object under test is calculated based on the following formula. :

[0031] ,

[0032] Among them, the difference in interference phase shift It includes an integer part and a fractional part, with the integer part being the second Raman two-photon detuning. Corresponding interference phase shift Mistuned with the first Raman photon two-photon Corresponding interference phase shift Intervals Integer multiples of, decimal part is .

[0033] As described above, step 3 includes the following steps:

[0034] Step 3.1: Remove the slit and turn off either the first frequency laser or the second frequency laser;

[0035] Step 3.2: Extract the encapsulated phase from the interferometric electrical signal output from the first photodetector. Based on the package phase and the wavelength of the test laser The measured flight distance was obtained. Fractional distance :

[0036] ,

[0037] Step 3.3: Scan the test laser frequency at the set rate. The interference electrical signal output by the first photodetector is a time-beat frequency signal. Extract the distance between the portion of the first beam splitter in the vacuum cavity and the portion of the second beam splitter in the vacuum cavity from the time-beat frequency signal, as an approximation of the flight distance. ;

[0038] Step 3.4: Approximate flight distance Distance from decimal Obtain the measured flight distance :

[0039] .

[0040] As described above, step 4 includes the following steps:

[0041] Step 4.1: Measure the actual flight time. and the corresponding measured flight distance The actual flight times are recorded separately. and the corresponding measured flight distance ,in Indicates the number of loops. The initial value is 1;

[0042] Step 4.2, when the loop count... The preset number of cycles was not reached. When the parallel spacing between the first and second beams in the vacuum cavity is changed, return to step 2, and repeat the cycle a certain number of times. Add 1;

[0043] When the number of loops Reach the preset number of cycles At that time, the difference method was used to determine the time from all measured flight times. and the corresponding measured flight distance Obtain the measured flight speed of the test object. .

[0044] As described above, step 2.2 specifically includes the following steps:

[0045] Outside the vacuum chamber, either the first or second beam splitter is blocked, leaving one beam to scan the intensity of the test laser. Each time the intensity of the test laser is adjusted, the test object is simultaneously ejected to interact with one beam, and the corresponding fluorescence signal is detected using a probe laser and a second photodetector. When a complete Rabi oscillation is observed, the intensity of the test laser corresponding to half the maximum fluorescence signal intensity is fixed. Then, the beam splitter is removed.

[0046] As described above, step 2.3 of a single-round Ramsey interferometry includes the following steps:

[0047] Step 2.3.1: Cool and project the object under test using an atomic interferometer, projecting the object under test in the positive x-axis direction;

[0048] Step 2.3.2: The object under test passes through each beam of light in sequence, thereby sequentially splitting and combining the matter waves.

[0049] Step 2.3.3: After the matter waves are combined, the test object is excited by the detection laser to produce fluorescence, and the corresponding fluorescence signal is obtained by the second photodetector.

[0050] Compared with the prior art, the present invention has the following advantages:

[0051] 1. This invention utilizes optical paths and experimental arrangements to design a method for measuring the wavelength of atomic matter waves. Through optical interference, phase information is extracted from the interference signal and converted into position information, allowing for convenient and rapid extraction of the distance information between the first and second beams. An interference loop is constructed using matter wave interference, thereby accurately measuring the flight time of the measured matter. This invention proposes a novel method and experimental design for measuring the wavelength of matter waves.

[0052] 2. This invention is highly suitable for atomic interferometers. During the research of atomic interferometers, the flight speed also needs to be accurately measured, which can be decomposed into the precise measurement of atomic flight speed and flight distance. The atomic flight time can be accurately measured using Ramsey interference fringes, while the flight distance of the object under test is measured by the test laser path. These methods, unaffected by changes in the initial position of the object under test, improve measurement sensitivity through interferometer phase measurement. Therefore, it can improve the measurement of the object's flight speed and be used for the precise measurement of matter wave wavelengths. Attached Figure Description

[0053] Figure 1 This is a schematic diagram of the system for measuring laser spacing according to the present invention; wherein, the length direction of the vacuum cavity is the x-axis direction, the height direction of the vacuum cavity is the y-axis direction, and the thickness direction of the vacuum cavity is the z-axis direction; The measured flight distance of the object under test is equal to the distance between the first and second beams in the vacuum cavity;

[0054] Figure 2 A schematic diagram illustrating the use of an atomic interferometer for measuring the time-of-flight of an object under test.

[0055] In the diagram: P1 - First polarizing beam splitter, used for beam splitting; P2 - Second polarizing beam splitter, used to change the laser direction; P3 - Third polarizing beam splitter, used to change the laser direction; P4 - Fourth polarizing beam splitter, used for beam combining; P5 - Fifth polarizing beam splitter, used for signal extraction.

[0056] PD1 - First photodetector; PD2 - Second photodetector;

[0057] L1 - Probe laser; L2 - Test laser;

[0058] H1 - First half-wave plate; H2 - Second half-wave plate; H3 - Third half-wave plate;

[0059] Q1 - First quarter-wave plate; Q2 - Second quarter-wave plate;

[0060] D1 - Launch point; D2 - Beam splitting point; D3 - Beam combining point; D4 - Detection point;

[0061] C1 - Vacuum cavity. Detailed Implementation

[0062] To facilitate understanding and implementation of the present invention by those skilled in the art, the present invention will be further described in detail below with reference to embodiments. It should be understood that the embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0063] Example 1

[0064] A device for measuring the wavelength of atomic matter waves, such as Figure 1 As shown, the atomic interferometer includes a vacuum cavity C1, a test laser L2, a probe laser L1, a first photodetector PD1, a second photodetector PD2, and a beam splitting and combining system for the optical path (including a first polarizing beam splitter P1, a second polarizing beam splitter P2, a third polarizing beam splitter P3, a fourth polarizing beam splitter P4, a fifth polarizing beam splitter P5, a first half-wave plate H1, a second half-wave plate H2, a third half-wave plate H3, a first quarter-wave plate Q1, and a second quarter-wave plate Q2), specifically configured as follows:

[0065] Within the vacuum cavity C1, the length direction of the vacuum cavity C1 is taken as the x-axis, the height direction as the y-axis, and the thickness direction as the z-axis. The x-axis, y-axis, and z-axis are mutually perpendicular. The output light from the first and second frequency lasers, after passing through a beam combiner (such as a fiber optic combiner), serves as the test laser L2. The test laser L2, fixed by a coupling head, is split into a first beam and a second beam. Both the first and second beams are incident parallel to the y-axis and pass through the vacuum cavity C1 before being combined to obtain a combined beam. That is, the portions of the first and second beams within the vacuum cavity C1 are both parallel to the y-axis. The combined beam is detected by a first photodetector PD1. A detection laser L1 also illuminates the vacuum cavity C1, and the second beam, the first beam, and the detection laser L1 are arranged sequentially along the x-axis within the vacuum cavity C1. A second photodetector PD2 is installed outside the vacuum cavity C1 at a position corresponding to the probe laser L1.

[0066] To facilitate subsequent testing of the measured flight distance of the test object from the first beam splitter to the second beam splitter. This invention will measure the flight distance. The optical path difference associated with the two beams (the first beam and the second beam) is rectangular, from the moment the test laser L2 is split into the first and second beams to the moment the first and second beams are combined to obtain the combined beam. In this embodiment, the first beam is always parallel to the y-axis before combining. The second beam is split from the first beam in a direction perpendicular to the first beam (i.e., parallel to the x-axis), then passes through the vacuum cavity C1 parallel to the y-axis, and then combines with the first beam in a direction parallel to the x-axis. Specifically, the optical path is as follows: the test laser L2 first passes through the first half-wave plate H1 for polarization adjustment, thereby controlling the beam splitting ratio. Then, it passes through the first polarizing beam splitter P1 to obtain the first and second beams. The first beam passes through the first polarizing beam splitter P1 and the second quarter-wave plate Q2 in sequence, then passes through the vacuum cavity C1 of the atomic interferometer in a direction parallel to the y-axis, and then combines with the first beam in a direction parallel to the x-axis. The first beam is incident on the fourth polarizing beam splitter P4 along the x-axis. Simultaneously, the second beam is reflected by the first polarizing beam splitter P1, then passes through the third half-wave plate H3 parallel to the x-axis, and after being redirected by the second polarizing beam splitter P2, it also passes through the first quarter-wave plate Q1 parallel to the y-axis and through the vacuum cavity C1. After being reflected by the third polarizing beam splitter P3, it reaches the fourth polarizing beam splitter P4 parallel to the x-axis. At the fourth polarizing beam splitter P4, the first and second beams are combined to obtain a combined beam. The combined beam passes through the second half-wave plate H2 and the fifth polarizing beam splitter P5 and is then incident on the first photodetector PD1. The first photodetector PD1 outputs an interference signal.

[0067] The measured flight distance of the test object During the test, the test laser L2 is split after passing through the slit. The object under test is ejected from the ejection point D1 and begins its flight, interacting sequentially with the two split beams (the first and second split beams). Both the first and second split beams illuminate the object under test in a direction parallel to the y-axis, thus sequentially splitting and combining the matter waves. The location where the matter waves are split is denoted as the splitting point D2, and the location where the matter waves are combined is denoted as the combining point D3. Taking the direction from which the object under test is ejected to the detection point within the vacuum cavity C1 as the positive x-axis, the direction in which the object rises and falls is parallel to the y-axis. Inside the vacuum cavity C1, along the positive x-axis, after the combining point D3, the detection laser L1 is applied. A second photodetector PD2 is placed outside the vacuum cavity C1 at a position corresponding to the application of the detection laser L1. The location inside the vacuum cavity C1 where the detection laser L1 detects the object under test is denoted as the detection point D4. In this embodiment, the second beam splitter, the first beam splitter, and the probe laser L1 sequentially perform matter wave beam splitting, matter wave beam combining, and fluorescence excitation on the flying test object. The second beam splitter serves as the first Raman beam, and the first beam splitter serves as the second Raman beam. By constructing a double-slit Ramsey interference loop, the matter wave of the test object is split at the first Raman beam, thus initiating interference. After a certain flight time, the matter wave of the test object passes through the second Raman beam, completing the interference loop and forming interference. At this time, the fluorescence signal of the test object is detected using the second photodetector PD2 to measure the proportion of the energy states of the test object, obtaining Ramsey interference fringes, thereby obtaining the measured flight time of the test object from the first Raman beam to the second Raman beam. Related interferometric phase shifts. This is achieved by measuring the flight time. The relevant interferometric phase shift is converted into the measured flight time of the test object. The precise value.

[0068] When testing the actual flight distance of the object being tested The time (equivalent to measuring the parallel distance between the portion of the first beam splitter in vacuum cavity C1 and the portion of the second beam splitter in vacuum cavity C1) is achieved simply by removing the slit before the test laser L2 enters the first half-wave plate H1, allowing the test laser L2 to directly split into the first and second beams. The interference electrical signal obtained from the combined beam is acquired from the first photodetector PD1, from which the measured flight distance can be extracted. The relevant phase difference information allows for the extraction of the measured flight distance from the phase difference caused by the optical path difference between the two split beams. .

[0069] Because the parallel spacing between the portion of the first beam splitter in vacuum cavity C1 and the portion of the second beam splitter in vacuum cavity C1 is equivalent to the distance between the measured object and the measured time of flight. Corresponding measured flight distance Through actual flight time and measured flight distance The measured flight speed of the object was obtained. Thus, the wavelength of matter waves can be obtained. The precise measurement value.

[0070] The analyte is an atom, molecule, or ion.

[0071] Example 2

[0072] A method for measuring the wavelength of atomic matter waves, utilizing the atomic matter wave wavelength measuring device described in Example 1, specifically includes the following steps:

[0073] Step 1: Construct the atomic matter wave wavelength measurement device described in Example 1.

[0074] In this embodiment, based on the preset interference region length (corresponding to the preset parallel spacing between the first beam splitter and the second beam splitter in the vacuum cavity C1), the initial positions of the second polarizing beam splitter P2, the third polarizing beam splitter P3, and the first quarter-wave plate Q1 along the x-axis are set.

[0075] Step 2: Both the first frequency laser and the second frequency laser are input into the beam combiner. A slit is placed after the beam combiner. In this embodiment, the slit is placed between the beam combiner and the first half-wave plate H1, with a slit width of 1-10 mm. This adjusts the test laser L2 incident on the first half-wave plate H1 into slit light. In the atomic interferometer, the test object is projected in the positive x-axis direction, and the measured flight time of the test object is measured. :

[0076] Step 2.1: Place a slit after the beam combiner so that the test laser L2 is the slit light before beam splitting; In this embodiment, a slit is placed between the beam combiner and the first half-wave plate H1, and the test laser L2 incident on the first half-wave plate H1 is adjusted to be the slit light, so that the two split beams can be used as the first Raman light and the second Raman light in the double-slit Ramsey interference loop.

[0077] Step 2.2: Adjust the intensity of the test laser L2 so that the first and second beams obtained by the test laser L2 are equivalent to π / 2 pulses, ensuring that the substance under test passes through the interaction region.

[0078] In traditional interferometers, a π / 2 pulse is achieved by adjusting the timing of the laser pulse. This application reduces the spot size of the test laser L2, thereby decreasing the measured flight time caused by the time it takes for the object under test to pass through the spot. Extending the time, thereby increasing the acquisition of measured flight time. The accuracy.

[0079] The interaction time between the test object and the beam splitter is recorded as follows: Each time the test object passes through the beam splitter corresponding to the test laser L2, the interaction time between the test object and the beam splitter is recorded as follows: The corresponding Rabi frequency is adjusted by changing the intensity of the test laser L2. , making This makes the test laser L2 equivalent to a π / 2 pulse light.

[0080] In this embodiment, outside the vacuum cavity C1, either the first or second beam splitter is blocked, leaving one beam splitter. The intensity of the test laser L2 is scanned (the ratio of the intensity of the first frequency laser to the intensity of the second frequency laser is fixed). The intensity of the test laser L2 is adjusted each time, and the test object is ejected once to allow the test object to interact with one beam splitter. The corresponding fluorescence signal is detected using the detection laser L1 and the second photodetector PD2. When a complete Rabi oscillation is observed, the intensity of the test laser L2 corresponding to half of the maximum fluorescence signal intensity is fixed, and then the beam splitter blocking is removed. At this time, the first and second beam splitters are equivalent to π / 2 pulsed light.

[0081] Step 2.3: Detuning of Raman two-photon signals Perform linear scanning, adjusting Raman two-photon mistuning each time. One round of Ramsey interferometry is completed by ejecting the test object once, and the fluorescence signal of the corresponding test object is collected to obtain the Ramsey interference fringes, such as... Figures 1-2 As shown.

[0082] One round of Ramsey interferometry includes cooling and ejecting the test object; the test object sequentially passing through various beams of light for matter wave splitting and combining; and fluorescence excitation and detection after matter wave combining. Specifically, it includes the following processes:

[0083] Step 2.3.1: Cool and project the object under test using an atomic interferometer, projecting the object under test in the positive x-axis direction;

[0084] Step 2.3.2: The object under test passes through each beam of light in sequence, thereby sequentially splitting and combining the matter waves. In this embodiment, the object under test interacts with the second beam of light at the beam splitting point D2, thereby splitting the matter waves and starting interference. After flying for a certain period of time, the matter waves of the object under test pass through the first beam of light at the beam combining point D3, completing the interference loop and forming interference.

[0085] Step 2.3.3: After the matter waves are combined, they continue to fly and reach the detection point D4. The detection laser L1 is used to excite the analyte to produce fluorescence, and the corresponding fluorescence signal is detected by the second photodetector PD2.

[0086] When time-of-flight measurement is performed, the spatial position of the object being measured at the moment of interaction with the laser is the starting and ending point of the corresponding atomic flight time. Therefore, the atomic flight distance is determined, that is, the parallel distance between the first beam and the second beam in the vacuum cavity C1 is equivalent to the flight distance of the object being measured in the interference region of the vacuum cavity C1.

[0087] Step 2.4: Fit the Ramsey interference fringes based on the following formula:

[0088] ,

[0089] The independent variable in the fitting is Raman two-photon detuning. , Indicating Raman two-photon detuning The corresponding fluorescence signal intensity is positively correlated with the population of the analyte and serves as the dependent variable in the fit. The amplitude of the fluorescence signal intensity. For the initial phase, The measured flight time is the free evolution time of the object under test between the two split laser beams, and is the value to be solved. Raman two-photon detuning The corresponding interference phase shift, and the fitting process in step 2.4, yields the Raman two-photon detuning. The corresponding interference phase shift;

[0090] Step 2.5: From the fitting results, take the first Raman two-photon detuning. And the corresponding interference phase shift is denoted as (equal ), taking the first Raman light two-photon detuning Second Raman two-photon mistuning with different values and the corresponding interference phase shift (equal The measured flight time of the object is calculated based on the following formula. :

[0091] ,

[0092] Among them, the difference in interference phase shift It includes an integer part and a fractional part, with the integer part being the second Raman two-photon detuning. Corresponding interference phase shift Mistuned with the first Raman photon two-photon Corresponding interference phase shift Intervals Integer multiples of, decimal part is ∈ .

[0093] Step 3: Stop launching the object to be tested, remove the slit, and use the first photodetector PD1 to detect the interference signal output by the combined beam. Measure the parallel distance between the first and second beams in the vacuum cavity C1 to obtain the measured flight distance of the object after passing through the first and second beams. .

[0094] Step 3.1: Remove the slit and turn off one of the first frequency laser and the second frequency laser (or block the first frequency laser or the second frequency laser before the beam combiner). In this embodiment, the intensity of the test laser L2 is increased so that the interference fringes detected by the first photodetector PD1 can be observed later. At this time, there is no object ejected. The two beams (i.e., the first beam and the second beam) pass directly through the vacuum cavity C1 and are combined to reach the first photodetector PD1. The combined beam generates an interference signal on the first photodetector PD1, and the first photodetector PD1 outputs an interference electrical signal.

[0095] The first and second beams are coherent beams with the same frequency. After traveling through different paths, they generate a distance-dependent phase difference. The phase difference between the first and second beams is related to the measured flight distance. Correlation, phase difference Included in the interference signal. The phase difference between the first and second beams due to the difference in optical path length. for:

[0096] ,

[0097] This refers to the phase change of the optical path of the first beam splitter from beam splitting to beam combining with the second beam splitter, that is, the phase change of the first beam splitter from the first polarizing beam splitter P1 to the fourth polarizing beam splitter P4.

[0098] This refers to the phase change of the second beam from its initial split to its final combination with the first beam, corresponding to the optical path length variation. Specifically, it represents the phase change of the second beam as it passes sequentially from the first polarizing beam splitter P1 through the second polarizing beam splitter P2, the third polarizing beam splitter P3, and finally the fourth polarizing beam splitter P4. This refers to the phase change of the second beam splitter from the second polarizing beam splitter P2 to the third polarizing beam splitter P3; The phase change of the second beam splitter from the first polarizing beam splitter P1 to the second polarizing beam splitter P2 is described. The phase change of the second beam from the third polarizing beam splitter P3 to the fourth polarizing beam splitter P4 is due to the fact that the test laser L2 is split into the first and second beams, and then combined to form the combined beam. The shape of the intermediate optical path is rectangular. ,and ,but Phase difference middle Extract the integer multiples of the phase difference. It has the following forms:

[0099] ,

[0100] in, This indicates that the phase difference includes Quantity, For the wrapping phase.

[0101] Step 3.2: Extract the encapsulated phase from the interference electrical signal output by the first photodetector PD1. Based on the package phase and the wavelength of the test laser The measured flight distance was obtained. Fractional distance :

[0102] ,

[0103] Step 3.3: Scan the frequency of the test laser L2 at the set rate. The interference electrical signal output by the first photodetector PD1 is a time-beat frequency signal. Extract the distance between the portion of the first beam splitter in the vacuum cavity C1 and the portion of the second beam splitter in the vacuum cavity C1 from the time-beat frequency signal. Use this distance as an approximation of the flight distance of the test object from the beam splitting point D2 to the beam recombining point D3. .

[0104] Step 3.4: Approximate flight distance Distance from decimal Obtain the measured flight distance :

[0105] .

[0106] Step 4: Measured flight distance obtained from precise measurements and measured flight time Then, accurate measured flight speed was obtained. .

[0107] Perform steps 2-3 once, according to the formula. The measured flight speed was obtained. In existing time-of-flight measurement techniques, the measured flight speed is highly dependent on the positioning of the launch point D1, which has uncertainties, thus introducing errors. However, this invention focuses primarily on the path from the split point D2 to the rejoining point D3 during the flight of the object under test, so fluctuations in the launch point D1 will not affect the measurement results.

[0108] Furthermore, to reduce measurement errors, multiple pairs of measured flight times were obtained through repeated measurements. Corresponding measured flight distance The measured flight speed was obtained by combining the differential method. Specifically, it includes the following steps:

[0109] Step 4.1: Measure the actual flight time. and the corresponding measured flight distance The actual flight times are recorded separately. and measured flight distance ,in Indicates the number of loops. The initial value is 1;

[0110] Step 4.2, when the loop count... The preset number of cycles was not reached. hour( ( ), change the preset interference region length, that is, change the parallel spacing between the first beam splitter and the second beam splitter in the vacuum cavity C1, return to step 2, and repeat the cycle a certain number of times. Add 1;

[0111] In this embodiment, after changing the preset interference region length, the second polarizing beam splitter P2, the third polarizing beam splitter P3, and the first quarter-wave plate Q1 are translated along the x-axis direction to adjust the parallel spacing between the first beam splitter and the second beam splitter in the preset vacuum cavity C1; the translation distance is 1~5cm each time.

[0112] When the number of loops Reach the preset number of cycles At that time, the difference method was used to obtain all the measured flight times. and the corresponding measured flight distance Obtain the measured flight speed of the test object. :

[0113] ,

[0114] ,

[0115] in, Indicates the first The measured flight distance was obtained by sub-difference calculation.

[0116] Thanks to the precise measurement of flight distance and flight time, the measured flight speed The accuracy meets the requirements for measuring the wavelength of matter waves.

[0117] Step 5: Obtain the wavelength of the matter wave using the following formula. Precise measurement value:

[0118] ,

[0119] in The wavelength of matter waves, is Planck's constant. The mass of the object being measured.

[0120] Laser cooling of the analyte in an atomic interferometer and extraction of the interference phase shift after atomic interference are common techniques, which will not be discussed in detail in this invention.

[0121] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. An atomic matter wave wavelength measuring apparatus comprising a vacuum chamber (Cl) of an atomic interferometer, characterized in that, The length direction of the vacuum cavity (C1) is the x-axis direction, the height direction of the vacuum cavity (C1) is the y-axis direction, the output light of the first frequency laser and the second frequency laser through the beam combining device is the test laser (L2), the test laser (L2) is split into first split light and second split light, the first split light and the second split light are incident in the direction parallel to the y-axis and pass through the vacuum cavity (C1) to be combined to obtain combined light, the combined light is detected by the first photodetector (PD1), and the vacuum cavity (C1) is also irradiated with the probe laser (L1), and the second split light, the first split light and the probe laser (L1) in the vacuum cavity (C1) are arranged along the x-axis direction in sequence; a second photodetector (PD2) is arranged at a position corresponding to the probe laser (L1) outside the vacuum cavity (C1); Wherein, from the test laser (L2) being split into first split light and second split light to the first split light and the second split light being combined to obtain combined light, the shape surrounded by the intermediate light path is a rectangle; Test the measured object of the measured time of flight When the test laser (L2) passes through the slit and then is spectrally split, the direction from being projected to being detected of the measured object in the vacuum cavity (C1) is the positive direction of the x-axis, the second beam splitting, the first beam splitting light, and the detection laser (L1) sequentially perform the material wave beam splitting, the material wave beam combining, and the fluorescence excitation on the flying measured object; The measured flying distance of the test object is tested When the slit is removed, the test laser (L2) directly performs light splitting.

2. The apparatus of claim 1, wherein The test laser (L2) is polarized by the first half-wave plate (H1), and then split into first split light and second split light by the first polarizing beam splitter (P1), the first split light is transmitted through the first polarizing beam splitter (P1) and the second quarter-wave plate (Q2) in sequence, then passes through the vacuum cavity (C1) in the direction parallel to the y-axis, and is incident on the fourth polarizing beam splitter (P4) in the direction parallel to the y-axis; at the same time, the second split light is reflected by the first polarizing beam splitter (P1), then passes through the third half-wave plate (H3) in the direction parallel to the x-axis, and is transmitted through the first quarter-wave plate (Q1) in the direction parallel to the y-axis and the vacuum cavity (C1) after changing direction by the second polarizing beam splitter (P2), and then reflected by the third polarizing beam splitter (P3) in the direction parallel to the x-axis to reach the fourth polarizing beam splitter (P4); the first split light and the second split light are combined at the fourth polarizing beam splitter (P4) to obtain combined light; the combined light is incident on the first photodetector (PD1) after passing through the second half-wave plate (H2) and the fifth polarizing beam splitter (P5), and the first photodetector (PD1) outputs an interference electric signal.

3. The apparatus of claim 1, wherein The measured object is an atom or a molecule or an ion.

4. A method of measuring the wavelength of an atomic matter wave using the atomic matter wave wavelength measuring apparatus according to claim 1, characterized by, The method comprises the following steps: Step 1, building an atomic matter wave wavelength measurement device; Step 2, the first frequency laser and the second frequency laser are input into a beam combining device, a slit is placed after the beam combining device, and the measured object is projected to the positive direction of the x axis in a vacuum cavity (C1) of the atomic interferometer to measure the measured time of flight ; Step 3, stopping the projection of the measured object, removing the slit, and using the interference electrical signal output by the first photoelectric detector (PD1) to measure the parallel distance between the first split light and the second split light in the vacuum cavity (C1), thereby obtaining the actual flight distance of the measured object through the first split light and the second split light ; Step 4, measured flight distance and measured flight time to obtain measured flight speed .

5. The method of claim 4, wherein the wavelength of the atomic matter wave is measured by a method comprising: The method further comprises the following steps: Step 5, obtain the precise measurement of the wavelength of the matter wave by the equation λ = 2πh / p ， wherein is the wavelength of the matter wave, is Planck's constant, is the mass of the measured object.

6. The atomic matter-wave wavelength measurement method of claim 4, wherein The step 2 comprises the following steps: Step 2.1, placing a slit after the beam combining device to adjust the test laser (L2) to be slit light; Step 2.2, adjusting the corresponding Rabi frequency by adjusting the intensity of the test laser (L2) such that so that the first and second beamsplit light obtained by beamsplitting the test laser (L2) are equivalent to a π / 2 pulse light, is the interaction time of the object to be measured with the beamsplit light; Step 2.3, adjusting the Raman two-photon detuning performing linear scanning each time the Raman two-photon detuning is adjusted corresponding to launching a sample object, completing a round of Ramsey interference measurement, and collecting the fluorescence signal of the corresponding sample object, and then obtaining the Ramsey interference fringes; Step 2.4, fitting the Ramsey interference fringes based on the following formula: ， wherein the fitting independent variable is the Raman two-photon detuning , denotes the Raman two-photon detuning the corresponding fluorescence signal intensity; is the amplitude of the fluorescence signal intensity, is the initial phase, is the measured time-of-flight, i.e. the free evolution time of the measured object between the two split laser beams, and is the value to be solved for; is the Raman two-photon detuning the corresponding interference phase shift, the fitting process of step 2.4 yields the respective Raman two-photon detunings the corresponding interference phase shift; Step 2.5, from the fitting result, take the first Raman light two-photon detuning and the corresponding interference phase shift is recorded as , take the second Raman light two-photon detuning with a different value from the first Raman light two-photon detuning and the corresponding interference phase shift ; solve the measured flight time of the measured object based on the following formula : ， wherein the difference of the interference phase shifts comprises an integer part and a decimal part, the integer part being the two-photon detuning of the second Raman light corresponding interference phase shift the two-photon detuning of the first Raman light corresponding interference phase shift is an integer multiple of the difference between the integer part, the decimal part being .

7. The atomic matter-wave wavelength measurement method of claim 4, wherein The step 3 comprises the following steps: Step 3.1, removing the slit and turning off one of the first frequency laser and the second frequency laser; Step 3.

2. Extracting the wrapped phase from the interference electrical signal output from the first photodetector (PD1) Based on the wrapped phase and the wavelength of the test laser The measured flight distance is obtained : ， Step 3.3, scan the frequency of the test laser (L2) at a set rate, the interference electrical signal output by the first photodetector (PD1) is a time beat frequency signal, the distance between the part of the first split beam in the vacuum cavity (C1) and the part of the second split beam in the vacuum cavity (C1) is extracted from the time beat frequency signal as an approximation of the flight distance ; Step 3.4, approximation of the flight distance by a small number with a small number of decimal places obtaining the measured flight distance : 。 8. The atomic matter-wave wavelength measurement method of claim 4, wherein, The step 4 comprises the following steps: Step 4.1, measuring a measured flight time and a corresponding measured flight distance , respectively denoted measured flight time and corresponding measured flight distance , wherein denotes the number of loops, the initial value of which is 1; Step 4.2, when the cycle number reaches the preset cycle number , change the parallel distance between the first split light and the second split light in the vacuum cavity (C1), return to step 2, and increase the cycle number by 1; When the number of loops Reach the preset number of cycles At that time, the difference method was used to determine the time from all measured flight times. and the corresponding measured flight distance Obtain the measured flight speed of the test object. .

9. The method of claim 6, wherein the wavelength of the atomic matter wave is measured by a method comprising: The step 2.2 specifically comprises the following steps: Outside the vacuum cavity (C1), the first beam-splitting light or the second beam-splitting light is shielded, and one beam-splitting light is reserved to scan the intensity of the test laser (L2); each time the intensity of the test laser (L2) is adjusted, the measured object is projected once to make the measured object interact with one beam-splitting light, and the corresponding fluorescent signal is detected by using the probe laser (L1) and the second photodetector (PD2); when complete Rabi oscillation is observed, the intensity of the test laser (L2) corresponding to the fluorescent signal intensity being half of the maximum fluorescent signal intensity is fixed; and then the shielding of the beam-splitting light is removed.

10. The method of claim 6, wherein the wavelength of the atomic matter wave is measured by a method comprising: The one round of Ramsey interference measurement in step 2.3 includes the following steps: Step 2.3.1, cooling and projecting the measured object by using the atomic interferometer, and projecting the measured object to the positive direction of the x-axis; Step 2.3.2, the measured object sequentially passes through each beam-splitting light, so that the matter wave beam splitting and the matter wave beam combining are sequentially performed; Step 2.3.3, after the matter wave beam combining, the measured object is excited to generate fluorescence by using the probe laser (L1), and the corresponding fluorescent signal is detected by using the second photodetector (PD2).

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