Interferometer device for high-precision wavelength measurement

Abstract

The present invention discloses an interferometer device for high-precision wavelength measurement, which comprises a housing and an optical mechanism arranged inside the housing. The optical mechanism includes an independent interferometer and a combined interferometer arranged in parallel from left to right. The independent interferometer includes a rear cavity mirror of the No. V interferometer and a front cavity mirror of the No. V interferometer arranged in front of it. The combined interferometer includes a combined rear cavity mirror and a front cavity mirror of the combined interferometer arranged in front of it. The combined rear cavity mirror includes a rear cavity mirror of the No. I interferometer, a rear cavity mirror of the No. II interferometer, a rear cavity mirror of the No. III interferometer, and a rear cavity mirror of the No. IV interferometer stacked in sequence from bottom to top. The present invention provides an interferometer device for high-precision wavelength measurement, integrates five Fizeau interferometers in a sealed cavity, simplifies the measurement optical system, and at the same time proposes a simple wavelength measurement method, which can achieve a wavelength measurement accuracy of 10-7.

Description

Technical Field

[0001] The invention belongs to the field of high-precision wavelength measurement, and in particular relates to an interferometer device for high-precision wavelength measurement. Background Art

[0002] A large number of applications in scientific research and production fields such as spectral research and optical communications require high-precision wavelength measurement. Interference is the most commonly used method for wavelength measurement. The equal-thickness interference of the Fizeau interferometer can be used to measure the wavelength of pulsed lasers and continuous lasers. High-precision wavelength measurement requires the joint application of multiple Fizeau interferometers of different thicknesses. Usually, a more complex optical system is required to collimate and split the measurement light, or collimate it after splitting it, and input it into multiple interferometers at the same time, resulting in a more complex system optical path. Summary of the invention

[0003] The object of the present invention is to provide an interferometer device for high-precision wavelength measurement to solve one or more of the above-mentioned technical problems.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] An interferometer device for high-precision wavelength measurement comprises a shell and an optical mechanism arranged inside the shell, wherein the optical mechanism comprises an independent interferometer and a combined interferometer which are arranged in parallel on the left and right sides, wherein the independent interferometer comprises a No. V interferometer rear cavity mirror and a No. V interferometer front cavity mirror arranged in front of the independent interferometer; the combined interferometer comprises a combined rear cavity mirror and a combined interferometer front cavity mirror arranged in front of the combined rear cavity mirror, wherein the combined rear cavity mirror comprises a No. I interferometer rear cavity mirror, a No. II interferometer rear cavity mirror, a No. III interferometer rear cavity mirror and a No. IV interferometer rear cavity mirror which are stacked in sequence from bottom to top.

[0006] In the above technical solution, the shell includes a main frame, a cover plate arranged at both ends of the main frame, a light-transmitting window and a vacuum adjustment structure; a light-transmitting hole is formed in the middle of the cover plate; the light-transmitting window is arranged between the cover plate and the main frame; the vacuum adjustment structure includes an air hole and a vacuum valve stem formed on the top surface of the main frame, the air hole is a vertically arranged through hole, the vacuum valve stem is horizontally arranged and passes through the air hole, the vacuum valve stem is rotatably connected to the top surface of the main frame 1, and a connecting hole is formed thereon.

[0007] In the above technical solution, the main frame is a rectangular frame structure with both left and right ends open; the cover plate is fixedly connected to the main frame by screws.

[0008] In the above technical solution, a fixing groove is formed on the side of the cover plate that contacts the light-transmitting window, and the light-transmitting window is embedded in the fixing groove and bonded to the bottom of the fixing groove.

[0009] In the above technical solution, a sealing ring is arranged between the light-transmitting window and the main frame; a sealing groove is formed at the contact end surface of the main frame and the light-transmitting window, and the sealing ring is embedded in the sealing groove.

[0010] In the above technical solution, the surface of the vacuum valve stem and the surface of the air hole are sealed by vacuum grease.

[0011] In the above technical solution, the optical mechanism is installed on the inner bottom surface of the main frame through the optical base plate; a cushion block is arranged between the rear cavity mirror of the No. Ⅰ interferometer and the optical base plate.

[0012] In the above technical solution, the interferometer rear cavity mirror No. Ⅰ, the interferometer rear cavity mirror No. Ⅱ, the interferometer rear cavity mirror No. Ⅲ and the interferometer rear cavity mirror No. Ⅳ are arranged flush with the end faces of one side away from the combined interferometer front cavity mirror, and the lengths of the light beam directions of the four interferometer rear cavity mirrors are different; the distance between the interferometer rear cavity mirror No. Ⅴ and the interferometer front cavity mirror No. Ⅴ is greater than the distance between the front and rear cavity mirrors in any combined interferometer.

[0013] In the above technical scheme, the interferometer rear cavity mirror No. 11 and the interferometer rear cavity mirror No. 2, 12, the interferometer rear cavity mirror No. 2 and 13, the interferometer rear cavity mirror No. 3 and 14, as well as the interferometer rear cavity mirror No. 1 and the gasket, the gasket and the optical base plate, the interferometer rear cavity mirror No. 5 and the optical base plate, and the interferometer front cavity mirror No. 5 and the optical base plate are all bonded to each other by optical glue.

[0014] In the above technical solution, the optical mechanism is made of fused quartz glass.

[0015] The beneficial effects of the present invention are:

[0016] The present invention provides an interferometer device for high-precision wavelength measurement, which integrates five Fizeau interferometers in a sealed cavity, simplifies the measurement optical system, and can achieve 10 -7 Wavelength measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the external structure of the interferometer device for high-precision wavelength measurement of the present invention;

[0018] Figure 2 is a cross-sectional view of an interferometer device for high-precision wavelength measurement of the present invention;

[0019] Figure 3 It is a schematic diagram of the structure of the optical mechanism in the interferometer device for high-precision wavelength measurement of the present invention.

[0020] in:

[0021] 1 Main frame 2 Cover plate

[0022] 3 light holes 4 air holes

[0023] 5 Sealing groove 6 Vacuum valve stem

[0024] 7 connecting hole 8 light-transmitting window

[0025] 9 optical base plate 10 cushion block

[0026] 11 Interferometer back cavity mirror No. 12 Interferometer back cavity mirror No. 2

[0027] 13. Interferometer rear cavity mirror No. Ⅲ 14. Interferometer rear cavity mirror No. Ⅳ

[0028] 15 combined interferometer front cavity mirror 16 No. Ⅴ interferometer back cavity mirror

[0029] Interference fringes of No. 17Ⅴ interferometer front cavity mirror No. 18Ⅰ

[0030] Interference fringes No. 19Ⅱ.

[0031] For ordinary technicians in this field, other relevant drawings can be obtained based on the above drawings without any creative work. DETAILED DESCRIPTION

[0032] In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0033] like Figures 1 to 3 As shown, an interferometer device for high-precision wavelength measurement includes a shell and an optical mechanism arranged inside the shell.

[0034] The shell includes a main frame 1, cover plates 2 arranged at both ends of the main frame 1, light-transmitting windows 8 and a vacuum adjustment structure.

[0035] The main frame 1 is a rectangular frame structure with both left and right ends open; the cover plate 2 is fixedly connected to the main frame 1 by screws, and a light-transmitting hole 3 is formed in the middle of the cover plate 2; the light-transmitting window 8 is arranged between the cover plate 2 and the main frame 1.

[0036] In this embodiment, in order to ensure the stable installation of the light-transmitting window 8, a fixing groove is formed on the side of the cover plate 2 that contacts the light-transmitting window 8, and the light-transmitting window 8 is embedded in the fixing groove and bonded to the bottom of the fixing groove.

[0037] In this embodiment, in order to further improve the sealing performance inside the housing, a sealing ring is provided between the light-transmitting window 8 and the main frame 1 .

[0038] In this embodiment, in order to facilitate the fixing of the sealing ring, a sealing groove 5 is formed at the contact end surface of the main frame 1 and the light-transmitting window 8 , and the sealing ring is embedded in the sealing groove 5 .

[0039] The vacuum adjustment structure includes an air vent 4 formed on the top surface of the main frame 1 and a vacuum valve stem 6. The air vent 4 is a vertically arranged through hole that connects the inner cavity of the main frame 1 with the external space. The vacuum valve stem 6 is horizontally arranged and passes through the air vent 4. The vacuum valve stem 6 is rotatably connected to the top surface of the main frame 1, and a connecting hole 7 is formed thereon. When the connecting hole 7 is rotated to be parallel to the air vent 4, the inner cavity of the main frame 1 is connected to the atmosphere, and the inner cavity of the main frame 1 can be evacuated. After the evacuation is completed, the vacuum valve stem 6 is rotated so that the connecting hole 7 deviates from the air vent 4, thereby achieving sealing of the inner cavity of the main frame 1.

[0040] In this embodiment, in order to improve the sealing performance of the inner cavity of the main frame 1, the surface of the vacuum valve stem 6 and the surface of the air hole 4 are sealed by vacuum grease.

[0041] In this embodiment, in order to reduce the impact of the environment on the measurement, 10 -7 The measurement accuracy requires that when the inner cavity of the main frame 1 is evacuated, the evacuation pressure should be at the Pa level.

[0042] The optical mechanism is installed on the inner bottom surface of the main frame 1 through an optical bottom plate 9; the optical mechanism includes an independent Fizeau interferometer and a combined Fizeau interferometer arranged in parallel on the left and right sides.

[0043] The combined Feszew interferometer includes a combined rear cavity mirror and a combined interferometer front cavity mirror 15 arranged in front of the combined rear cavity mirror. The combined rear cavity mirror includes interferometer rear cavity mirror No. Ⅰ 11, interferometer rear cavity mirror No. Ⅱ 12, interferometer rear cavity mirror No. Ⅲ 13 and interferometer rear cavity mirror No. Ⅳ 14 stacked in sequence from bottom to top, thereby forming four interferometers No. Ⅰ to Ⅳ F1 to F4 sharing the same front cavity mirror.

[0044] The interferometer rear cavity mirror No. 1 11, the interferometer rear cavity mirror No. 2 12, the interferometer rear cavity mirror No. 3 13 and the interferometer rear cavity mirror No. 4 14 are arranged flush with the end faces on one side away from the combined interferometer front cavity mirror 15, and the lengths of the four interferometer rear cavity mirrors are different, that is, the distances from the end faces on one side of the interferometer rear cavity mirror No. 1 1, the interferometer rear cavity mirror No. 2 12, the interferometer rear cavity mirror No. 3 13 and the interferometer rear cavity mirror No. 4 14 close to the combined interferometer front cavity mirror 15 to the combined interferometer front cavity mirror 15 are not the same.

[0045] The interferometer back cavity mirror No. 11, the interferometer back cavity mirror No. 2, the interferometer back cavity mirror No. 3, the interferometer back cavity mirror No. 4, the interferometer back cavity mirror No. 13, and the interferometer back cavity mirror No. 4 can be stacked in any order. In this embodiment, the interferometer back cavity mirror No. 11, the interferometer back cavity mirror No. 2, the interferometer back cavity mirror No. 3, the interferometer back cavity mirror No. 4 ...12, the interferometer back cavity mirror No. 13, and the interferometer back cavity mirror No. 4 are stacked in order from long to short. The design wavelength accuracy of the interferometer back -3 , each interferometer is improved by 10 times in turn.

[0046] The independent Fizeau interferometer includes a No. V interferometer rear cavity mirror 16 and a No. V interferometer front cavity mirror 17, and the distance between the two is greater than the distance between the front and rear cavity mirrors in any combination of Fizeau interferometers. The accuracy of the independent Fizeau interferometer is 10 -7 The independent Fizeau interferometer is the interferometer No. V in the optical mechanism of the present invention.

[0047] The bottom surface and cavity surface of the combined interferometer front cavity mirror 15 and the No. V interferometer front cavity mirror 17 have an angle of 90°±100 milliradians, so that the first to fifth interferometers form a wedge angle of 100 milliradians.

[0048] The optical mechanism adopts fused quartz glass to reduce the temperature coefficient of the interferometer, and each cavity mirror is a rectangular parallelepiped structure.

[0049] In this embodiment, a spacer 10 is provided between the interferometer No. Ⅰ rear cavity mirror 11 and the optical base plate 9 to provide a certain height.

[0050] In this embodiment, the interferometer rear cavity mirror No. 11 and the interferometer rear cavity mirror No. 2, 12, the interferometer rear cavity mirror No. 2 and the interferometer rear cavity mirror No. 3, 13 and the interferometer rear cavity mirror No. 4, 14, as well as the interferometer rear cavity mirror No. 1 and the gasket 10, the gasket 10 and the optical base plate 9, the interferometer rear cavity mirror No. 5 and the optical base plate 9, and the interferometer front cavity mirror No. 5 and the optical base plate 9 are all bonded to each other by optical glue.

[0051] Working process of the present invention:

[0052] The collimated light beam is incident into the interferometer through the light-transmitting hole 3 of the front cover, wherein the combined Fessau interferometer formed by interferometers I to IV forms interference fringes I 18, the height of the rear cavity mirrors I to IV is designed to be 7 mm, the interference fringes 18 formed by interferometers I to IV are 28 mm high, and a linear array CCD is used for fringing collection. An independent Fessau interferometer forms an independent interference fringes II 19, and an independent linear CCD is used for fringing collection.

[0053] The wavelength calculation principle of the present invention is:

[0054] The rough wavelength of interferometer I is calculated based on the interference fringe spacing between the measurement light and the reference light: Where es and er are the bright fringe spacings of the measured wavelength and the reference wavelength, λ r The reference wavelength is used for interferometers II to V. The wavelength is calculated by using the measured wavelength of the previous stage as the rough wavelength. The rough wavelength is first used to determine the interference order, and then the precise wavelength of each stage is obtained by combining the fringe phase. The wavelength accuracy of interferometer I is 10 -3Each additional interferometer increases the accuracy by one order of magnitude. The wavelength measurement accuracy of interferometer V can reach 10 -7 .

[0055] The specific calculation process is as follows:

[0056] Using interferometer F1, we get the approximate wavelength of Where es1 and er1 are the bright fringe spacings between the measured laser wavelength and the reference laser wavelength on interferometer F1, λ r is the reference laser wavelength, λ 0 The accuracy is better than 10 -2 .

[0057] Using Lambda 0 Calculate the interference order of the measured laser at the bright fringe on interferometer F1 No. Ⅰ: Int[] indicates rounding within the middle number. r1 is the thickness of the interferometer at the reference light fringe adjacent to the measured light, is the pre-calibrated thickness, Δe 1 e is the distance between the adjacent bright fringes of the measured light and the reference light, r1 is the reference light fringe spacing.

[0058] The precise wavelength obtained by using interferometer F1 is Its relative accuracy is 10 -3 .

[0059] The precise wavelength λ obtained by interferometer F1 1 As the rough wavelength for wavelength measurement using interferometer II, calculate the interference order of the measured laser at the bright fringe on interferometer F2: h r2 is the thickness of the interferometer at the reference light fringe adjacent to the measured light, is the pre-calibrated thickness, Δe 2 e is the distance between the adjacent bright fringes of the measured light and the reference light, r2 is the reference light fringe spacing.

[0060] The precise wavelength obtained by using interferometer F2 is Its relative accuracy is 10 -4 .

[0061] By analogy, we can use F3, F4 and F5 to get the precision of 10 -5 , 10 -6 and 10 -7 The wavelength measurement value.

[0062] The present invention integrates five interferometers from thin to thick in a sealed cavity, and can output two sets of interference fringes through a collimated beam, thereby improving the integration level and effectively simplifying the optical system. At the same time, the measurement process is simple and the accuracy is guaranteed, which can achieve 10 -7 Wavelength measurement accuracy.

[0063] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. An interferometer device for high-precision wavelength measurement, Features: The invention comprises a shell and an optical mechanism arranged inside the shell, wherein the optical mechanism comprises an independent interferometer and a combined interferometer arranged in parallel on the left and right sides, wherein the independent interferometer comprises a No. V interferometer rear cavity mirror (16) and a No. V interferometer front cavity mirror (17) arranged in front of the independent interferometer; the combined interferometer comprises a combined rear cavity mirror and a combined interferometer front cavity mirror (15) arranged in front of the independent interferometer; the combined rear cavity mirror comprises a No. I interferometer rear cavity mirror (11), a No. II interferometer rear cavity mirror (12), a No. III interferometer rear cavity mirror (13) and a No. IV interferometer rear cavity mirror (14) stacked in sequence from bottom to top.

2. The high-precision wavelength measurement interferometer device according to claim 1, Features: The shell comprises a main frame (1), a cover plate (2) arranged at both ends of the main frame (1), a light-transmitting window (8) and a vacuum adjustment structure; a light-transmitting hole (3) is formed in the middle of the cover plate (2); the light-transmitting window (8) is arranged between the cover plate (2) and the main frame (1); the vacuum adjustment structure comprises an air hole (4) and a vacuum valve stem (6) formed on the top surface of the main frame (1); the air hole (4) is a vertically arranged through hole; the vacuum valve stem (6) is horizontally arranged and passes through the air hole (4); the vacuum valve stem (6) is rotatably connected to the top surface of the main frame (1), and a connecting hole (7) is formed on the vacuum valve stem (6).

3. The high-precision wavelength measurement interferometer device according to claim 2, Features: The main frame (1) is a rectangular frame structure with both left and right ends open; the cover plate (2) is fixedly connected to the main frame (1) by means of screws.

4. The high-precision wavelength measurement interferometer device according to claim 2, Features: A fixing groove is formed on the side of the cover plate (2) that contacts the light-transmitting window (8), and the light-transmitting window (8) is embedded in the fixing groove and bonded to the bottom of the fixing groove.

5. The high-precision wavelength measurement interferometer device according to claim 2, Features: A sealing ring is arranged between the light-transmitting window (8) and the main frame (1); a sealing groove (5) is formed at the contact end surfaces of the main frame (1) and the light-transmitting window (8), and the sealing ring is embedded in the sealing groove (5).

6. The high-precision wavelength measurement interferometer device according to claim 2, Features: The surface of the vacuum valve stem (6) and the surface of the air vent (4) are sealed by vacuum grease.

7. The high-precision wavelength measurement interferometer device according to claim 1, Features: The optical mechanism is installed on the inner bottom surface of the main frame (1) through an optical bottom plate (9); a cushion block (10) is arranged between the No. 1 interferometer rear cavity mirror (11) and the optical bottom plate (9).

8. The high-precision wavelength measurement interferometer device according to claim 1, Features: The interferometer rear cavity mirror No. Ⅰ (11), the interferometer rear cavity mirror No. Ⅱ (12), the interferometer rear cavity mirror No. Ⅲ (13) and the interferometer rear cavity mirror No. Ⅳ (14) are arranged flush with the end faces of one side away from the combined interferometer front cavity mirror (15), and the lengths of the light beam directions of the four interferometer rear cavity mirrors are different; the distance between the interferometer rear cavity mirror No. Ⅴ (16) and the interferometer front cavity mirror No. Ⅴ (17) is greater than the distance between the front and rear cavity mirrors in any combined interferometer.

9. The high-precision wavelength measurement interferometer device according to claim 1, Features: The interferometer rear cavity mirror (11) No. 1 and the interferometer rear cavity mirror (12) No. 2, the interferometer rear cavity mirror (12) No. 3 and the interferometer rear cavity mirror (13), the interferometer rear cavity mirror (13) No. 4 and the interferometer rear cavity mirror (14), as well as the interferometer rear cavity mirror (11) No. 1 and the cushion block (10), the cushion block (10) and the optical base plate (9), the interferometer rear cavity mirror (16) No. 5 and the optical base plate (9), and the interferometer front cavity mirror (17) No. 5 and the optical base plate (9) are all bonded to each other by means of optical glue.

10. The high-precision wavelength measurement interferometer device according to claim 1, Features: The optical mechanism is made of fused quartz glass.

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