A high-precision right-angle detection device and detection method

Abstract

The present invention discloses a high-precision right-angle detection device and a high-precision right-angle detection method. The present invention adopts two right-angle surfaces of an original part to be tested to reflect laser light, and uses incident laser light and outgoing laser light to measure the ion spectrum of metastable lithium ions to calculate the first-order Doppler effect of the incident laser light and the outgoing laser light. Then, the first-order Doppler effect is used to infer the angle between the incident laser light and the outgoing laser light, and finally the right-angle angle of the original part to be tested is calculated. The method of the present invention can improve the accuracy of angle measurement to within 0.01 arc seconds, reaching or even exceeding 10 ‑8 Radians; the present invention adopts the ion transition spectrum line frequency as a reference, which is a natural and stable reference source and does not require regular calibration. It can also use atomic transition spectrum lines or molecular transition spectrum lines as references. There are many ions, atoms, or molecules and corresponding spectrum lines available, and the wavelength coverage range is wide, which can be diversified.

Description

Technical Field

[0001] The present invention belongs to the technical field of angle precision measurement, and in particular relates to a high-precision right-angle detection device, and also relates to a high-precision right-angle detection method. Background Art

[0002] Angle measurement is of great significance and application in precision measurement and positioning. In precision machining in industrial manufacturing, such as aerospace, automobile manufacturing, and electronic component manufacturing, angle accuracy is crucial to the quality and performance of products. Small angle errors may lead to serious assembly problems or functional deviations; in the calibration of optical systems and equipment, such as laser equipment, optical instruments, photolithography machines, etc., high-precision angle measurement or evaluation directly affects imaging quality and measurement accuracy. In addition, in navigation and attitude control, metrology and standards, construction and engineering measurement, etc., high-precision angle measurement or evaluation is required to ensure the reliability and high precision of navigation, metrology, engineering, etc. In these fields, small angle deviations may cause serious problems. Therefore, high-precision angle measurement plays an important role in promoting technological progress, improving product quality and safety assurance.

[0003] In particular, the precise measurement of right angles is very important in many fields, especially in places where it is necessary to build or ensure the verticality, parallelism and geometric accuracy of structural components, optical paths, etc. For example, in high-precision optical equipment such as lithography machines or precision optical experiments, the verticality and parallelism between some components are directly related to the final equipment performance and the accuracy of research results. For example, right-angle mirrors and right-angle prisms are excellent tools for achieving parallel light paths. If an absolute right angle can be achieved, the absolute parallelism of the light paths can be achieved. Therefore, it is crucial to process or screen such components with right angles that are completely or infinitely close to 90°. At present, the most accurate angle measurement devices should be photoelectric autocollimators and laser interferometers. The photoelectric autocollimator calculates the change in angle by emitting a light comb and detecting the offset of the light beam after emission. The accuracy is usually in the sub-arc second level, 10 -6 The laser interferometer measures the angle by measuring the phase difference caused by the interference of laser beams, with an accuracy of 0.01 arc second. -7 radian. Summary of the invention

[0004] The purpose of the present invention is to provide a high-precision right angle detection device and a high-precision right angle detection method in view of the above-mentioned problems existing in the prior art.

[0005] The above-mentioned purpose of the present invention is achieved by the following technical means:

[0006] A high-precision right-angle detection device comprises an original part to be tested, an ion source, a laser modulation module, a fluorescence collection module, and a data processing module. The laser modulation module generates an incident laser that is injected into one of the right-angle surfaces of the original part to be tested, and after two reflections, an outgoing laser is reflected from the other right-angle surface. The ion source prepares ions and leads them out to form an ion beam with a set speed, and then the ion beam is collimated and the collimated ion beam is emitted in a direction perpendicular to the incident laser. The collimated ion beam passes through the incident laser and the outgoing laser. The incident laser and the outgoing laser excite ion transitions, and the ions emit fluorescence signals. The fluorescence collection module collects the fluorescence signals emitted by the ions and converts them into electrical signals and outputs them to the data processing module. The data processing module obtains the saturated absorption spectrum line type according to the electrical signal and the laser frequency output by the laser modulation module, and obtains the center frequency of the saturated absorption spectrum by fitting. The data processing module is also connected to the ion source, the laser modulation module, and the fluorescence collection module respectively through signal transmission lines.

[0007] As mentioned above, the incident laser is parallel to the angular bisector of the two right-angled surfaces of the original to be measured, and the plane where the incident laser and the outgoing laser are located is perpendicular to the angular bisector of the two right-angled surfaces of the original to be measured.

[0008] As described above, the laser modulation module includes a laser, an acousto-optic modulator, a first fiber coupling head, a second fiber coupling head, an optical fiber, and a horizontal displacement frame. The output end of the laser is connected to the laser input end of the acousto-optic modulator, the laser output end of the acousto-optic modulator is connected to one end of the optical fiber through the first fiber coupling head, the other end of the optical fiber is connected to the second fiber coupling head, the second fiber coupling head is arranged on the horizontal displacement frame, the second fiber coupling head and the original part to be tested are located at the same height, and the second fiber coupling head is aligned with one of the right-angle surfaces of the original part to be tested; the data processing module is also connected to the modulation input end of the acousto-optic modulator and the laser through a signal transmission line.

[0009] As mentioned above, the fluorescence collection module includes an imaging lens and a photomultiplier tube. The data processing module is also connected to the photomultiplier tube through a signal transmission line. The imaging lens focuses the fluorescence signal emitted by the ions onto the photosensitive surface of the photomultiplier tube. After the photomultiplier tube detects the fluorescence signal, it converts the fluorescence signal into a voltage pulse signal, and outputs the voltage pulse signal to the data processing module. The data processing module obtains the saturated absorption spectrum line shape according to the voltage pulse signal and the laser frequency output by the laser, and fits the center frequency of the saturated absorption spectrum.

[0010] As mentioned above, the ion source can be replaced by an atomic source or a molecular source.

[0011] A high-precision right angle detection method, using the high-precision right angle detection device as described above, comprises the following steps:

[0012] Step 1: The data processing module turns on the ion source, which prepares ions and draws out ions to form an ion beam at a set speed, and then outputs the collimated ion beam;

[0013] Step 2: Move the horizontal displacement frame, the data processing module turns on the laser and the acousto-optic modulator, the acousto-optic modulator outputs the incident laser to the first right-angle surface of the original part to be measured, and after two reflections, the outgoing laser is reflected from the second right-angle surface, and the first measurement is performed to obtain the saturated absorption spectrum line shape of the first measurement, and the center frequency of the first measurement is obtained according to the saturated absorption spectrum line shape of the first measurement. ;

[0014] Step 3, move the horizontal displacement frame again, the data processing module turns on the laser and the acousto-optic modulator, the acousto-optic modulator outputs the incident laser to the second right-angle surface of the original to be measured, and after two reflections, the outgoing laser is reflected from the first right-angle surface, and a second measurement is performed to obtain the saturated absorption spectrum line shape of the second measurement, and the center frequency of the second measurement is obtained according to the saturated absorption spectrum line shape of the second measurement. ;

[0015] Step 4: Based on the center frequency of the first measurement and the center frequency of the second measurement Calculate the angle of the original part to be measured ;

[0016] Step 5: Repeat steps 2 to 4 multiple times to obtain the angles of multiple original parts to be tested. , and then the angles of multiple original parts to be measured Perform weighted averaging to obtain the final angle of the original part to be measured.

[0017] As described above, the laser path of the first measurement is opposite to the laser path of the second measurement.

[0018] As mentioned above, step 4 calculates the angle of the original to be measured based on the following formula :

[0019] ,

[0020] ,

[0021] In the formula, is the angle between the incident laser and the outgoing laser, is the true frequency of ion transition, is the ratio of the ion velocity to the speed of light.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) The present invention uses the ion transition spectrum line frequency as a reference, which is a natural and stable reference source and does not require regular calibration. Atomic transition spectrum lines or molecular transition spectrum lines can also be used as references.

[0024] (2) The present invention uses an ion beam (which can also be replaced by an atomic beam or a molecular beam) for measurement. There are many ions (atoms or molecules) and corresponding spectral lines available for use, and the wavelength coverage range is wide, which can be diversified.

[0025] (3) The measurement accuracy of the present invention is high, exceeding 0.01 arc seconds. By optimizing the ion (atom or molecule) system and increasing the ion (atom or molecule) speed, the measurement accuracy can be further improved to 0.001 arc seconds, far exceeding the current traditional methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a flow chart of the method of the present invention;

[0027] Figure 2 is a schematic structural diagram of a device according to Embodiment 1 of the present invention;

[0028] FIG3 (a) is a schematic diagram of an incident laser beam incident on a first right-angle surface and reflected twice to be an outgoing laser beam from a second right-angle surface according to Embodiment 2 of the present invention;

[0029] FIG3( b ) is a schematic diagram of an incident laser beam hitting the second right-angle surface and reflecting the outgoing laser beam from the first right-angle surface after two reflections according to Embodiment 2 of the present invention;

[0030] FIG4( a ) is a transition spectrum diagram of metastable lithium ions in Example 2 of the present invention;

[0031] FIG4( b ) is a graph showing the residual error of the transition spectrum line type fitting of the metastable lithium ion in Example 2 of the present invention;

[0032] Reference numerals and corresponding component names:

[0033] 1—part to be tested; 101—first right-angled surface; 102—second right-angled surface; 201—incident laser; 203—exiting laser; 205—angle between incident laser and exiting laser; 301—photomultiplier tube; 302—imaging lens; 401—first reference surface; 402—angle between second right-angled surface and first reference surface; 403—second reference surface; 404—angle between first right-angled surface and second reference surface; 5—ion beam; 501—ion source; 602—data processing module; 603—laser; 604—acousto-optic modulator; 605—first optical fiber coupling head; 606—optical fiber; 607—second optical fiber coupling head; 608—horizontal displacement frame. DETAILED DESCRIPTION

[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. The embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0035] Embodiment 1:

[0036] A high-precision right-angle detection device includes a test element 1, an ion source (in this embodiment, an ion source of metastable lithium ions is selected), a laser modulation module, a fluorescence collection module, and a data processing module 602. The test element 1 includes two right-angle surfaces, and the right-angle angle between the two right-angle surfaces is the right-angle angle to be measured. The laser modulation module outputs a single-frequency single-mode incident laser 201, and the incident laser 201 is parallel to the angle bisector of the two right-angle surfaces of the test element 1. The incident laser 201 is incident on one of the right-angle surfaces of the test element 1, and after two reflections, an outgoing laser 203 is reflected from the other right-angle surface. The ion source of metastable lithium ions prepares metastable lithium ions and leads them out to form a set speed (in this embodiment, the set speed is 1.1×10 5 m / s), then collimate the ion beam and emit the collimated ion beam in a direction perpendicular to the incident laser 201, the collimated ion beam passes through the incident laser 201 and the exit laser 203, the incident laser 201 and the exit laser 203 excite the metastable lithium ions to transition and emit fluorescence signals, the fluorescence collection module collects the fluorescence signals emitted by the metastable lithium ions and converts them into electrical signals and outputs them to the data processing module 602, the data processing module 602 obtains the saturated absorption spectrum line shape according to the electrical signal and the laser frequency output by the laser modulation module, and obtains the center frequency of the saturated absorption spectrum by fitting, and the data processing module 602 is also connected to the ion source, the laser modulation module, and the fluorescence collection module through signal transmission lines.

[0037] The incident laser 201 is parallel to the angular bisector of the two right-angled surfaces of the original to be measured 1 , and the plane where the incident laser 201 and the outgoing laser 203 are located is perpendicular to the angular bisector of the two right-angled surfaces of the original to be measured 1 .

[0038] The lithium ion source in this embodiment may also be replaced by an ion source of other ions, or an atomic source, or a molecular source (such as a helium atomic beam source, a calcium atomic beam source, or an iodine molecular beam source).

[0039] The laser modulation module includes a laser 603, an acousto-optic modulator 604, a first fiber coupling head 605, a second fiber coupling head 607, an optical fiber 606, and a horizontal displacement frame 608. The output end of the laser 603 is connected to the laser input end of the acousto-optic modulator 604. The laser output end of the acousto-optic modulator 604 is connected to one end of the optical fiber 606 through the first fiber coupling head 605. The other end of the optical fiber 606 is connected to the second fiber coupling head 607. The second fiber coupling head 607 is arranged on the horizontal displacement frame 608. The second fiber coupling head 607 is located at the same height as the original component 1 to be tested. The second fiber coupling head 607 is aligned with one of the right-angle surfaces of the original component 1 to be tested. The data processing module 602 is also connected to the modulation input end of the acousto-optic modulator 604 and the laser 603 through a signal transmission line.

[0040] The fluorescence collection module includes an imaging lens 302 and a photomultiplier tube 301. The data processing module 602 is also connected to the photomultiplier tube 301 through a signal transmission line. The imaging lens 302 focuses the fluorescence signal emitted by the metastable lithium ions onto the photosensitive surface of the photomultiplier tube 301. After detecting the fluorescence signal, the photomultiplier tube 301 converts the fluorescence signal into a voltage pulse signal, and outputs the voltage pulse signal to the data processing module 602. The data processing module 602 obtains the saturated absorption spectrum line shape according to the voltage pulse signal and the laser frequency output by the laser 603, and obtains the center frequency of the saturated absorption spectrum by fitting.

[0041] The laser 603 is used to generate a single-frequency single-mode incident laser 201; the acousto-optic modulator 604 is used to scan the laser frequency output by the laser 603 and output a frequency-sweeping laser; the horizontal displacement frame 608 places the second coupling head at the same height as the right-angle surface of the original component 1 to be tested, and adjusts the horizontal position of the second coupling head, so that the incident laser 201 transmitted to the second coupling head can be horizontally incident on the first right-angle surface 101 or the second right-angle surface 102 of the original component 1 to be tested.

[0042] The metastable lithium ion transition emits an isotropic fluorescence signal, wherein the fluorescence signal reaching the imaging lens 302 is collected. The imaging lens 302 is used to focus the collected fluorescence signal to the photosensitive surface position of the photomultiplier tube 301 (PMT). After the photomultiplier tube 301 detects the fluorescence signal, it is converted into a voltage pulse signal.

[0043] The data processing module 602 (which may be an industrial computer) controls and adjusts the parameters (such as wavelength and power) of the laser 603; the data processing module 602 is connected to the acousto-optic modulator 604 to scan the laser frequency for spectrum scanning; the data processing module 602 is used to read the voltage pulse signal of the fluorescence signal and synchronize the time with the frequency scanning of the acousto-optic modulator 604; the data processing module 602 also adjusts the position of the horizontal moving frame, thereby adjusting the horizontal position of the second coupling head.

[0044] Embodiment 2:

[0045] A high-precision right-angle detection method, using a high-precision right-angle detection device described in Example 1, comprises the following steps:

[0046] The present invention uses two right-angled surfaces of the original part 1 to be tested to reflect laser light, and uses the incident laser 201 and the outgoing laser 203 to measure the ion spectrum of metastable lithium ions to calculate the first-order Doppler effect of the incident laser 201 and the outgoing laser 203, and then the first-order Doppler effect is used to infer the angle difference between the incident laser 201 and the outgoing laser 203 (that is, the angle 205 between the incident laser 201 and the outgoing laser 203), and finally the right angle of the original part 1 to be tested is calculated. The method of the present invention can improve the accuracy of angle measurement to within 0.01 arc seconds, reaching or even exceeding 10 -8 radian.

[0047] In this embodiment, an ion source of metastable lithium ions is used. The ion source of metastable lithium ions in this embodiment may also be replaced by an ion source of other ions, or an atomic source, or a molecular source.

[0048] Step 1: The data processing module 602 turns on the ion source of metastable lithium ions. The ion source of metastable lithium ions prepares metastable lithium ions and extracts the speed of forming metastable lithium ions. 1.1×10 5 m / s ion beam, and then output the collimated ion beam;

[0049] Step 2, move the horizontal displacement frame 608, the data processing module 602 turns on the laser 603 and the acousto-optic modulator 604, the acousto-optic modulator 604 outputs the incident laser 201 to the first right-angled surface 101 of the original part 1 to be measured, and after two reflections, the outgoing laser 203 is reflected from the second right-angled surface 102, and the first measurement is performed: the incident laser 201 and the outgoing laser 203 excite the metastable lithium ion transition and emit a fluorescence signal, and the photomultiplier tube 301 detects the fluorescence signal and converts the fluorescence signal into a voltage pulse signal, and outputs the voltage pulse signal to the data processing module 602, the data processing module 602 obtains the saturated absorption spectrum line shape of the first measurement according to the voltage pulse signal and the laser frequency output by the laser 603, and obtains the center frequency of the first measurement through Gaussian fitting according to the saturated absorption spectrum line shape of the first measurement According to the Doppler effect, we can get:

[0050] (1)

[0051] in, is the center frequency of the spectrum line obtained by fitting after the first measurement, is the true frequency of metastable lithium ion transition, ,Right now is the ion velocity of metastable lithium ions with the speed of light The ratio of is the angle 205 between the incident laser 201 and the outgoing laser 203 .

[0052] Step 3, move the horizontal displacement frame 608 again, the data processing module 602 turns on the laser 603 and the acousto-optic modulator 604, the acousto-optic modulator 604 outputs the incident laser 201 to the second right-angled surface 102 of the original part 1 to be measured, and after two reflections, the outgoing laser 203 is reflected from the first right-angled surface 101, and the second measurement is performed: the incident laser 201 and the outgoing laser 203 excite the metastable lithium ion transition and emit a fluorescence signal, and the photomultiplier tube 301 detects the fluorescence signal and converts the fluorescence signal into a voltage pulse signal, and outputs the voltage pulse signal to the data processing module 602, the data processing module 602 obtains the saturated absorption spectrum line shape of the second measurement according to the voltage pulse signal and the laser frequency output by the laser 603, and obtains the center frequency of the second measurement through Gaussian fitting according to the saturated absorption spectrum line shape of the second measurement According to the Doppler effect, we can get:

[0053] (2)

[0054] Step 4: Based on the center frequency of the first measurement and the center frequency of the second measurement Calculate the angle of the original part 1 to be tested ;

[0055] The center frequency of the spectrum line obtained after the first measurement is And the center frequency of the spectrum line obtained by fitting after the second measurement Do the difference and get , eliminated The term reduces the impact of inaccurate ion velocity, and we can get: (3)

[0056] As shown in FIG. 3( a ) and FIG. 3( b ), the first right-angled surface 101 of the original component 1 to be tested forms a right angle with the first reference surface 401 . Similarly, the second right-angled surface 102 of the original component 1 to be tested forms a right angle with the second reference surface 403 , then the angle 404 between the first right-angled surface 101 and the second reference surface 403 is exactly equal to the angle 402 between the second right-angled surface 102 and the first reference surface 401, and the angle 404 between the first right-angled surface 101 and the second reference surface 403 and the angle 402 between the second right-angled surface 102 and the first reference surface 401 are recorded as ,Depend on and The angle of the original part 1 to be tested can be obtained as: (4)

[0057] Step 5: Repeat steps 2 to 4 multiple times to obtain the angles of multiple original parts 1 to be tested. , and then the angles of the multiple original parts 1 to be tested are A weighted average is performed to further improve the precision and accuracy of the angle of the original part 1 to be measured, and the final angle of the original part 1 to be measured is obtained.

[0058] The present invention uses the saturation absorption spectrum of metastable lithium ions. The value is 546THz, The value is 3.4×10 -4 According to formula (3), the angle of the original part 1 to be tested is obtained The measurement accuracy is 5kHz / (546THz×3.4×10 -4 )=2.7×10 -8 radians, corresponding to 0.006 arc seconds.

[0059] The method of the present invention is to obtain a saturated absorption spectrum when the incident laser 201 and the outgoing laser 203 are parallel. The saturated absorption spectrum is the spontaneous emission fluorescence generated by the part of the ions whose moving speed is equal to the angle between the two beams of light (in this embodiment, the incident laser 201 and the outgoing laser 203) involved in the action. That is, the residual first-order Doppler frequency shift at the center of the obtained saturated absorption spectrum corresponds to the angle difference between the incident laser 201 and the outgoing laser 203, that is, the difference between the angle of the object to be measured and 90°, but the actual center frequency of the ion transition is Other system errors, such as the second-order Doppler frequency shift, are difficult to evaluate, so the angle difference cannot be determined by only one measurement. Therefore, a second measurement is introduced, that is, the object to be measured or the laser is moved so that the paths of the incident laser 201 and the outgoing laser 203 are reversed, so that another center frequency value can be obtained. The other error terms included in the center frequency values ​​of the two measurements are the same, and only the residual first-order Doppler term is equal and opposite. Therefore, the residual first-order Doppler term can be obtained based on the difference, and other errors are eliminated, and the laser angle difference is obtained, and finally the difference of the angle deviation of the original 1 to be measured from 90° is obtained.

[0060] The present invention In the visible light band, in the hundreds to thousands of terahertz (THz), the ion velocity is >10 5 m / s, corresponding to >3.3×10 -4 , The measurement accuracy can reach within kilohertz (kHz), so it can be deduced that The measurement accuracy is better than 1kHz / (100THz×3.3×10 -4 )=3×10 -8 Radians correspond to 0.007 arc seconds. The measurement accuracy exceeds the current mainstream angle measurement limit.

[0061] It should be noted that the embodiments described in the present invention are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the described embodiments or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the attached claims.

Claims

1. A high-precision right-angle detection method, characterized in that: The following steps are involved: Step 1, the data processing module (602) turns on the ion source (501), the ion source (501) prepares ions and extracts them to form an ion beam (5) with a set speed, and then outputs the collimated ion beam (5); Step 2: Move the horizontal displacement frame (608), the data processing module (602) turns on the laser (603) and the acousto-optic modulator (604), the acousto-optic modulator (604) outputs the incident laser (201) to the first right-angle surface (101) of the original component to be measured (1), and after two reflections, the outgoing laser (203) is reflected from the second right-angle surface (102), and the first measurement is performed to obtain the saturated absorption spectrum line shape of the first measurement, and the center frequency of the first measurement is obtained by fitting the saturated absorption spectrum line shape of the first measurement. ; Step 3, the horizontal displacement frame (608) is moved again, the data processing module (602) turns on the laser (603) and the acousto-optic modulator (604), the acousto-optic modulator (604) outputs the incident laser (201) to the second right-angle surface (102) of the original component (1) to be measured, and after two reflections, the outgoing laser (203) is reflected from the first right-angle surface (101), and a second measurement is performed to obtain the saturated absorption spectrum line shape of the second measurement, and the center frequency of the second measurement is obtained by fitting the saturated absorption spectrum line shape of the second measurement. ; Step 4: Based on the center frequency of the first measurement and the center frequency of the second measurement Calculate the angle of the original part (1) to be tested ; Step 5: Repeat steps 2 to 4 multiple times to obtain the angles of multiple original parts (1) to be tested. , and then the angles of the multiple original parts (1) to be tested are Perform weighted averaging to obtain the final angle of the original part (1) to be tested.

2. A high-precision right-angle detection method according to claim 1, characterized in that: The laser path of the first measurement is opposite to the laser path of the second measurement.

3. A high-precision right-angle detection method according to claim 2, characterized in that: The step 4 calculates the angle of the original part (1) to be tested based on the following formula: : ， ， In the formula, is the angle (205) between the incident laser (201) and the outgoing laser (203), is the true frequency of ion transition, is the ratio of the ion velocity to the speed of light.

4. A device for implementing the high-precision right-angle detection method according to claim 1, comprising a component to be tested (1), characterized in that: The invention also includes an ion source (501), a laser modulation module, a fluorescence collection module, and a data processing module (602). The laser modulation module generates an incident laser (201) which is injected into one of the right-angled surfaces of the original part (1) to be tested. After two reflections, an outgoing laser (203) is reflected from the other right-angled surface. The ion source (501) prepares ions and extracts them to form an ion beam (5) with a set speed. The ion beam (5) is then collimated and the collimated ion beam (5) is emitted in a direction perpendicular to the incident laser (201). The collimated ion beam (5) passes through the incident laser (2 01) and an outgoing laser (203), the incident laser (201) and the outgoing laser (203) excite ion transitions, and the ions emit fluorescence signals. The fluorescence collection module collects the fluorescence signals emitted by the ions and converts them into electrical signals and outputs them to the data processing module (602). The data processing module (602) obtains the saturated absorption spectrum line shape according to the electrical signal and the laser frequency output by the laser modulation module, and obtains the center frequency of the saturated absorption spectrum by fitting. The data processing module (602) is also connected to the ion source (501), the laser modulation module, and the fluorescence collection module through signal transmission lines.

5. The device according to claim 4, characterized in that: The incident laser (201) is parallel to the angular bisector of the two right-angled surfaces of the original part (1) to be tested, and the plane where the incident laser (201) and the outgoing laser (203) are located is perpendicular to the angular bisector of the two right-angled surfaces of the original part (1) to be tested.

6. The device according to claim 5, characterized in that: The laser modulation module comprises a laser (603), an acousto-optic modulator (604), a first optical fiber coupling head (605), a second optical fiber coupling head (607), an optical fiber (606), and a horizontal displacement frame (608); the output end of the laser (603) is connected to the laser input end of the acousto-optic modulator (604); the laser output end of the acousto-optic modulator (604) is connected to one end of the optical fiber (606) through the first optical fiber coupling head (605); the other end of the optical fiber (606) is connected to the second optical fiber coupling head (607); the second optical fiber coupling head (607) is arranged on the horizontal displacement frame (608); the second optical fiber coupling head (607) and the original component to be tested (1) are located at the same height; the second optical fiber coupling head (607) is aligned with one of the right-angled surfaces of the original component to be tested (1); The data processing module (602) is also connected to the modulation input end of the acousto-optic modulator (604) and the laser (603) via a signal transmission line.

7. The device according to claim 6, characterized in that: The fluorescence collection module comprises an imaging lens (302) and a photomultiplier tube (301); the data processing module (602) is also connected to the photomultiplier tube (301) via a signal transmission line; the imaging lens (302) focuses the fluorescence signal emitted by the ions onto a photosensitive surface of the photomultiplier tube (301); the photomultiplier tube (301) detects the fluorescence signal and converts the fluorescence signal into a voltage pulse signal, and outputs the voltage pulse signal to the data processing module (602); the data processing module (602) obtains a saturated absorption spectrum line shape according to the voltage pulse signal and the laser frequency output by the laser (603), and obtains the center frequency of the saturated absorption spectrum by fitting.

8. The device according to claim 7, characterized in that: The ion source (501) can be replaced by an atomic source or a molecular source.

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