A quadruple optical path interferometer

Abstract

The application discloses a four-fold optical path interferometer, wherein a first single-face total reflection mirror and a second single-face total reflection mirror are respectively arranged on a linear displacement platform and are perpendicular to each other; a beam splitter and a first target mirror are located on two sides of a double-face total reflection mirror, the first target mirror is perpendicular to the moving direction of the linear displacement platform; the first single-face total reflection mirror and a detector are located on two sides of the beam splitter, the first single-face total reflection mirror is parallel to the beam splitter; the second single-face total reflection mirror and a second target mirror are located on two sides of the double-face total reflection mirror, the second target mirror is parallel to the moving direction of the linear displacement platform, and the second single-face total reflection mirror is parallel to the double-face total reflection mirror; when the vertical distance between the center point of the double-face total reflection mirror and the linear displacement platform is a first distance, the vertical distance between the center point of the double-face total reflection mirror and the first target mirror is a second distance, and the vertical distance between the center point of the double-face total reflection mirror and the second target mirror is the sum of the second distance and 2 times the first distance.

Description

Technical Field

[0001] This application relates to the field of spectrometer technology, and more specifically, to a four-times optical path interferometer. Background Technology

[0002] Fourier Transform Infrared (FTIR) spectrometers are optical instruments that use an interferometer as their core. They extract the intensity of incident light at different frequencies by interfering with two beams of light through the principle of optical interference. They are commonly used for the rapid identification of compounds and are widely applicable in many fields, including chemistry, life sciences, and environmental monitoring.

[0003] There are various types of interferometers for FTIR, the most common of which is the Michelson interferometer. For example... Figure 1 As shown, the Michelson interferometer includes two planar total internal reflection mirrors, M1 and M2, a beam splitter G1, and a compensation plate G2. M1 is a fixed mirror, and M2 is a movable mirror connected to a precision screw; rotating the drum allows it to move forward and backward. The right surface of G1 is coated with a semi-transparent, semi-reflective film, splitting the incident light into two beams of equal intensity (reflected light and transmitted light). G2 is made of the same material and has the same thickness as G1, and is mounted parallel to each other. This ensures that the two beams participating in the interference pass through the glass plate an equal number of times, preventing any additional optical path difference introduced by the glass medium when they reach the observation area E. M1 and M2 are perpendicular, and G1 and G2 are parallel, with G1 and G2 forming 45-degree angles with M1 and M2, respectively. After the light source is projected onto G1 at an incident angle of 45 degrees, it splits into two beams. One beam is reflected light, which is reflected back to G1 through M1. The other beam is transmitted light, which passes through G2 and M2 and then returns to G1 along the same path. After these two beams return to G1, they interfere to reach the observation area E.

[0004] However, traditional Michelson interferometers are double optical path difference interferometers, meaning the optical path difference D changes with the moving mirror M2 by the formula D = 2d. Therefore, providing a higher optical path difference interferometer to reduce the moving distance and thus the overall structure size is a pressing issue. Summary of the Invention

[0005] This application provides a four-times optical path difference interferometer, which can provide an optical path difference interferometer with a higher magnification, thereby reducing the moving distance and thus reducing the overall size of the structure.

[0006] The specific technical solution is as follows:

[0007] In a first aspect, embodiments of this application provide a four-times optical path interferometer, the interferometer comprising: a semi-reflective and semi-transmissive beam splitter, a first single-sided total reflection mirror, a second single-sided total reflection mirror, a first target reflection mirror, a second target reflection mirror, a double-sided total reflection mirror, a linear displacement platform, and a detector, wherein the first target reflection mirror and the second target reflection mirror are both reflection mirrors capable of reflecting all light rays;

[0008] The first single-sided total reflection mirror and the second single-sided total reflection mirror are respectively tilted and disposed on the linear displacement platform, and the first single-sided total reflection mirror and the second single-sided total reflection mirror are perpendicular to each other;

[0009] The first single-sided total reflection mirror and the detector are located on opposite sides of the beam splitter, and the center points of the first single-sided total reflection mirror, the detector and the beam splitter are on the same straight line. The first single-sided reflection mirror is parallel to the beam splitter.

[0010] The second single-sided reflector and the second target reflector are located on opposite sides of the double-sided total reflection mirror, and the center points of the second single-sided reflector, the second target reflector and the double-sided total reflection mirror are on the same straight line. The second target reflector is perpendicular to the moving direction of the linear displacement platform, and the second single-sided total reflection mirror is parallel to the double-sided total reflection mirror.

[0011] The beam splitter and the first target mirror are located on opposite sides of the double-sided total reflection mirror, and the center points of the beam splitter, the first target mirror and the double-sided total reflection mirror are on the same straight line. The first target mirror is parallel to the moving direction of the linear displacement platform.

[0012] When the initial distance between the center point of the double-sided total reflection mirror and the center point of the second single-sided total reflection mirror is the first distance, and the vertical distance from the center point of the double-sided total reflection mirror to the first target reflection mirror is the second distance, the vertical distance from the center point of the double-sided total reflection mirror to the second target reflection mirror is the sum of the second distance and twice the first distance;

[0013] In this process, after the light source enters the beam splitter perpendicular to the direction of movement, it splits into a reflected beam path and a transmitted beam path. The reflected beam path passes sequentially through the first single-sided total reflection mirror, the second single-sided total reflection mirror, the double-sided total reflection mirror, and the first target reflection mirror, and is reflected back to the beam splitter along the original path. The transmitted beam path passes sequentially through the double-sided total reflection mirror and the second target reflection mirror, and is reflected back to the beam splitter along the original path. Finally, the light from the two paths interferes and reaches the detector.

[0014] In one possible implementation, the first target reflector is a corner reflector or a single-sided total reflection mirror, and / or the second target reflector is a corner reflector or a single-sided total reflection mirror.

[0015] In one possible implementation, the beam splitter, the first single-sided total reflection mirror, the second single-sided total reflection mirror, and the double-sided total reflection mirror are tilted at 45 degrees.

[0016] In one possible implementation, the beam splitter is made of any one of calcium fluoride, potassium bromide, and zinc selenide; and / or,

[0017] The detector includes any one of the following: mercury cadmium telluride detector, indium antimonide detector, lead selenide detector, DTGS detector, and indium gallium arsenide detector.

[0018] Secondly, this application provides a four-times optical path interferometer, which includes: a semi-reflective and semi-transmissive beam splitter, a first single-sided total reflection mirror, a second single-sided total reflection mirror, a first target reflection mirror, a second target reflection mirror, a linear displacement platform, and a detector. The first target reflection mirror and the second target reflection mirror are both reflection mirrors that can reflect all light.

[0019] The first single-sided total reflection mirror and the second single-sided total reflection mirror are respectively tilted and disposed on the linear displacement platform, and the first single-sided total reflection mirror and the second single-sided total reflection mirror are perpendicular to each other;

[0020] The first single-sided total reflection mirror and the detector are located on opposite sides of the beam splitter, and the center points of the first single-sided total reflection mirror, the detector and the beam splitter are on the same straight line. The first single-sided reflection mirror is parallel to the beam splitter.

[0021] The second target reflector is perpendicular to the moving direction of the linear displacement platform, the center lines of the beam splitter and the first target reflector are on the same straight line, and the first target reflector is located between the linear displacement platform and the second target reflector;

[0022] In this process, after the light source enters the beam splitter perpendicular to the direction of movement, it splits into a reflected beam path and a transmitted beam path. The reflected beam path passes sequentially through a first single-sided total reflection mirror, a second single-sided total reflection mirror, and a second target reflection mirror, and is reflected back to the beam splitter along the original path. The transmitted beam path passes sequentially through the first target reflection mirror and the second target reflection mirror, and is reflected back to the beam splitter along the original path. Alternatively, the transmitted beam path may only pass through the first target reflection mirror and is reflected back to the beam splitter along the original path. Finally, the light rays from the two paths interfere with each other and reach the detector.

[0023] The distance between the center point of the beam splitter and the center point of the first target reflector is such that the optical path difference between the reflected beam path and the transmitted beam path is four times the moving distance of the first single-sided total reflection mirror or the second single-sided total reflection mirror.

[0024] In one possible implementation, when the first target mirror is parallel to the second single-sided total reflection mirror, the transmitted beam passes sequentially through the first target mirror and the second target mirror in the optical path, and the distance between the center point of the beam splitter and the center point of the first target mirror is the sum of the third distance and twice the first distance.

[0025] The first distance is the initial distance between the center point of the beam splitter and the center point of the first single-sided total reflection mirror;

[0026] The third distance is the distance between the center point of the first single-sided total reflection mirror and the center point of the second single-sided total reflection mirror.

[0027] In one possible implementation, when the first target mirror is perpendicular to the second target mirror, the transmitted beam passes only through the first target mirror in the optical path, and the distance between the center point of the beam splitter and the center point of the first target mirror is 2 * first distance + second distance + third distance.

[0028] The first distance is the initial distance between the center point of the beam splitter and the center point of the first single-sided total reflection mirror;

[0029] The second distance is the perpendicular distance from the center point of the first target reflector to the second target reflector;

[0030] The third distance is the distance between the center point of the first single-sided total reflection mirror and the center point of the second single-sided total reflection mirror.

[0031] In one possible implementation, the first target reflector is a corner reflector or a single-sided total reflection mirror, and / or the second target reflector is a corner reflector or a single-sided total reflection mirror.

[0032] In one possible implementation, the beam splitter, the first single-sided total reflection mirror, and the second single-sided total reflection mirror are tilted at 45 degrees.

[0033] In one possible implementation, the beam splitter is made of any one of calcium fluoride, potassium bromide, and zinc selenide; and / or,

[0034] The detector includes any one of the following: mercury cadmium telluride detector, indium antimonide detector, lead selenide detector, DTGS detector, and indium gallium arsenide detector.

[0035] As described above, this invention provides a four-times optical path interferometer. This interferometer introduces two movable, mutually perpendicularly placed single-sided total internal reflection mirrors, allowing the optical path of the reflected beam to include a four-times moving distance. Furthermore, by setting the positions and distances of the first target mirror, the second target mirror, and the double-sided total internal reflection mirror (which may or may not be included), the optical path difference between the reflected and transmitted beam paths can be mutually canceled out at other distances, retaining only the four-times moving distance, thus achieving a four-times optical path interferometer. Compared to a traditional Michelson interferometer, to achieve the same optical path difference, the moving distance of the interferometer in this embodiment is 1 / 4 of the optical path difference, which is 1 / 2 of the moving distance of the Michelson interferometer. This indicates that, when applied to FTIR, the interferometer in this embodiment can achieve twice the spectral resolution of the Michelson interferometer with the same moving mirror moving distance. Moreover, the reduced moving distance also helps to reduce the volume of the linear displacement stage and miniaturize the overall structure.

[0036] The innovative aspects of this application's embodiments include:

[0037] 1. This invention provides a four-times optical path interferometer. By introducing two movable, mutually perpendicular single-sided total internal reflection mirrors, the optical path of the reflected beam can include a four-times moving distance. Furthermore, by setting the positions and distances of the first target mirror, the second target mirror, and the double-sided total internal reflection mirror (which may also be excluded), the optical path difference between the reflected beam and the transmitted beam can be mutually canceled at other distances, retaining only the four-times moving distance, thereby realizing a four-times optical path interferometer.

[0038] 2. This application embodiment implements a four-times optical path interferometer by setting the following structure:

[0039] The first and second single-sided total reflection mirrors are respectively tilted and mounted on the linear displacement platform, and the first and second single-sided total reflection mirrors are perpendicular to each other.

[0040] The first single-sided total reflection mirror and the detector are located on both sides of the beam splitter, and the center points of the first single-sided total reflection mirror, the detector and the beam splitter are on the same straight line. The first single-sided reflection mirror is parallel to the beam splitter.

[0041] The second single-sided reflector and the second target reflector are located on both sides of the double-sided total reflection mirror, and the center points of the second single-sided reflector, the second target reflector and the double-sided total reflection mirror are on the same straight line. The second target reflector is perpendicular to the moving direction of the linear displacement platform, and the second single-sided total reflection mirror is parallel to the double-sided total reflection mirror.

[0042] The beam splitter and the first target mirror are located on opposite sides of the double-sided total reflection mirror, and the center points of the beam splitter, the first target mirror and the double-sided total reflection mirror are on the same straight line. The first target mirror is parallel to the direction of movement of the linear displacement platform.

[0043] When the initial distance between the center point of the double-sided total reflection mirror and the center point of the second single-sided total reflection mirror is the first distance, and the perpendicular distance from the center point of the double-sided total reflection mirror to the first target reflection mirror is the second distance, the perpendicular distance from the center point of the double-sided total reflection mirror to the second target reflection mirror is the sum of the second distance and twice the first distance.

[0044] 3. This application embodiment implements another type of four-times optical path interferometer by setting the following structure:

[0045] The first and second single-sided total reflection mirrors are respectively tilted and mounted on the linear displacement platform, and the first and second single-sided total reflection mirrors are perpendicular to each other.

[0046] The first single-sided total reflection mirror and the detector are located on both sides of the beam splitter, and the center points of the first single-sided total reflection mirror, the detector and the beam splitter are on the same straight line. The first single-sided reflection mirror is parallel to the beam splitter.

[0047] The second target mirror is perpendicular to the direction of movement of the linear displacement platform. The center lines of the beam splitter and the first target mirror are on the same straight line, and the first target mirror is located between the linear displacement platform and the second target mirror.

[0048] In this process, after the light source enters the beam splitter perpendicular to the direction of movement, it is split into a reflected beam path and a transmitted beam path. The reflected beam path passes sequentially through the first single-sided total reflection mirror, the second single-sided total reflection mirror, and the second target reflection mirror, and is reflected back to the beam splitter along the original path. The transmitted beam path passes sequentially through the first target reflection mirror and the second target reflection mirror, and is reflected back to the beam splitter along the original path. Alternatively, the transmitted beam path passes only through the first target reflection mirror and is reflected back to the beam splitter along the original path. Finally, the light from the two paths interferes and reaches the detector.

[0049] The distance between the center point of the beam splitter and the center point of the first target reflector is such that the optical path difference between the reflected beam path and the transmitted beam path is four times the moving distance of the first or second single-sided total reflection mirror.

[0050] Specifically, when the first target reflector is parallel to the second single-sided total reflection mirror, the transmitted beam passes sequentially through the first target reflector and the second target reflector on its optical path. The distance between the center point of the beam splitter and the center point of the first target reflector is the sum of the second distance and twice the first distance. The first distance is the initial distance between the center point of the beam splitter and the center point of the first single-sided total reflection mirror. The second distance is the distance between the center points of the first single-sided total reflection mirror and the center points of the second single-sided total reflection mirror.

[0051] When the first target mirror is perpendicular to the second target mirror, the transmitted beam only passes through the first target mirror in its path, and the distance between the center point of the beam splitter and the center point of the first target mirror is 2 * first distance + second distance + third distance; the first distance is the initial distance between the center point of the beam splitter and the center point of the first single-sided total reflection mirror of the linear displacement platform; the second distance is the distance between the center points of the first and second single-sided total reflection mirrors; and the third distance is the perpendicular distance from the center point of the first target mirror to the second target mirror. Attached Figure Description

[0052] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0053] Figure 1 A schematic diagram of the structure of a Michelson interferometer provided for the present technology;

[0054] Figure 2 A schematic diagram of a four-times optical path interferometer provided in this application embodiment;

[0055] Figure 3 A schematic diagram of another four-way optical path interferometer provided in this application embodiment;

[0056] Figure 4 A schematic diagram of another four-way optical path interferometer provided in this application embodiment;

[0057] Figure 5 This is a schematic diagram of another four-times optical path interferometer provided in an embodiment of this application. Detailed Implementation

[0058] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0059] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The terms "comprising" and "having," and any variations thereof, in the embodiments and drawings of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or devices.

[0060] Because FTIR has a wide range of applications and there are many types of spectrometers, different spectrometer performance indicators are required for different applications. Among the more important performance indicators are: spectral range, signal-to-noise ratio, wavenumber accuracy, and sampling time.

[0061] "Spectral range" refers to the frequency range that FTIR can measure. FTIR spectral ranges are typically divided into near-infrared (NIR), mid-infrared (MIR), and far-infrared (FIR). Spectral range is a crucial indicator for evaluating FTIR performance and its applications. Because different molecules have different vibrational and rotational energy levels, they can be used to identify different substances. Different instruments have different spectral ranges, which directly determine the application scenarios of an FTIR instrument. The spectral range of an FTIR instrument is affected by many components, requiring consideration of the selection of infrared light source emission power and wavelength, as well as the choice of beam splitter and reflector, etc.

[0062] The signal-to-noise ratio (SNR) is the ratio of the signal strength measured by FTIR to the noise strength, reflecting the stability and reliability of the instrument. A higher SNR results in a more accurate FTIR spectral signal and more reliable spectral data.

[0063] "Spectral resolution" refers to the smallest wavelength or wavenumber difference that an FTIR instrument can resolve, which is the smallest distance between two adjacent peaks in the spectrum. Spectral resolution reflects the instrument's accuracy and sensitivity; higher resolution means clearer spectral details and a higher signal-to-noise ratio. Spectral resolution is inversely proportional to the maximum optical path difference. Therefore, to achieve high spectral resolution, an FTIR instrument with a large optical path difference must be selected. This leads to two problems: the large size of the FTIR instrument and a decrease in its signal-to-noise ratio. The large size significantly limits the applicability of the FTIR instrument.

[0064] To reduce the optical path difference in FTIR and decrease the size of FTIR, such as... Figure 2 As shown, this application provides a four-times optical path interferometer, which includes: a semi-reflective and semi-transparent beam splitter 11, a first single-sided total reflection mirror 12, a second single-sided total reflection mirror 13, a first target reflection mirror 14, a second target reflection mirror 15, a double-sided total reflection mirror 16, a linear displacement platform 17, and a detector 18. The first target reflection mirror 14 and the second target reflection mirror 15 are both reflection mirrors that can reflect all light.

[0065] The first single-sided total reflection mirror 12 and the second single-sided total reflection mirror 13 are respectively tilted on the linear displacement platform 17, and the first single-sided total reflection mirror 12 and the second single-sided total reflection mirror 13 are perpendicular to each other.

[0066] The beam splitter 11 and the first target mirror 14 are located on both sides of the double-sided total reflection mirror 16, and the center points of the beam splitter 11, the first target mirror 14 and the double-sided total reflection mirror 16 are on the same straight line. The first target mirror 14 is parallel to the moving direction of the linear displacement platform 17.

[0067] The first single-sided total reflection mirror 12 and the detector 18 are located on both sides of the beam splitter 11, and the center points of the first single-sided total reflection mirror 12, the detector 18 and the beam splitter 11 are on the same straight line. The first single-sided reflection mirror is parallel to the beam splitter 11.

[0068] The second single-sided reflector 13 and the second target reflector 15 are located on both sides of the double-sided total reflection mirror 16, and the center points of the second single-sided reflector 13, the second target reflector 15 and the double-sided total reflection mirror 16 are on the same straight line. The second target reflector 15 is perpendicular to the moving direction of the linear displacement platform 17, and the second single-sided total reflection mirror 13 is parallel to the double-sided total reflection mirror 16.

[0069] When the initial distance between the center point of the double-sided total reflection mirror 16 and the center point of the second single-sided reflection mirror 13 is the first distance, and the vertical distance from the center point of the double-sided total reflection mirror 16 to the first target reflection mirror 14 is the second distance, the vertical distance from the center point of the double-sided total reflection mirror 16 to the second target reflection mirror 15 is the sum of the second distance and twice the first distance.

[0070] The light source enters the beam splitter 11 perpendicular to the direction of movement and is split into a reflected beam path and a transmitted beam path. The reflected beam path passes sequentially through the first single-sided total reflection mirror 12, the second single-sided total reflection mirror 13, the double-sided total reflection mirror 16, and the first target reflection mirror 14, and is reflected back to the beam splitter 11 along the original path. The transmitted beam path passes sequentially through the double-sided total reflection mirror 16 and the second target reflection mirror 15, and is reflected back to the beam splitter 11 along the original path. Finally, the light from the two paths interferes and reaches the detector 18.

[0071] like Figure 3 As shown, if the first distance is represented by d1, the second distance by d2, and the moving distance of the linear displacement platform 17 by d, then the distance between the first single-sided total reflection mirror 12 and the beam splitter 11 is d+d1, and the distance between the second single-sided total reflection mirror 13 and the double-sided total reflection mirror 16 is d+d1. When the distance between the center points of the first single-sided total reflection mirror 12 and the second single-sided total reflection mirror 13 is the third distance d3, the distance between the center points of the beam splitter 11 and the double-sided total reflection mirror 16 is also d3. The optical path length of the reflected beam is 4d1+2d2+2d3+4d, the optical path length of the transmitted beam is 4d1+2d2+2d3, and the optical path difference between the two is D=4d.

[0072] It should be added that the first single-sided total reflection mirror 12 and the second single-sided total reflection mirror 13 move simultaneously.

[0073] This invention provides a four-times optical path interferometer. By introducing two movable, mutually perpendicularly placed single-sided total internal reflection mirrors, the optical path of the reflected beam includes a four-times moving distance. Furthermore, by setting the positions and distances of the first target mirror, the second target mirror, and the double-sided total internal reflection mirror, the optical path difference between the reflected and transmitted beams can be canceled out at other distances, retaining only the four-times moving distance, thus achieving a four-times optical path interferometer. Compared to a traditional Michelson interferometer, to achieve the same optical path difference, the moving distance of the interferometer in this embodiment is 1 / 4 of the optical path difference, which is half the moving distance of the Michelson interferometer. For example, the original 1cm moving distance is now reduced to only 0.25-0.5mm. This indicates that, when applied to FTIR, the interferometer of this embodiment can achieve twice the spectral resolution of the Michelson interferometer with the same moving mirror moving distance. Moreover, the reduced moving distance also helps to reduce the size of the linear displacement stage and miniaturize the overall structure.

[0074] In one embodiment, the first target reflector 14 is a corner reflector or a single-sided total reflection mirror, and / or the second target reflector 15 is a corner reflector or a single-sided total reflection mirror.

[0075] In one embodiment, the beam splitter 11, the first single-sided total reflection mirror 12, the second single-sided total reflection mirror 13, and the double-sided total reflection mirror 16 are tilted at 45 degrees.

[0076] When the tilt angle of the beam splitter 11, the first single-sided total reflection mirror 12, the second single-sided total reflection mirror 13, and the double-sided total reflection mirror 16 is 45 degrees, it can be ensured that the optical paths of the reflected beam and the transmitted beam only include two types of light rays: those parallel to the direction of movement and those perpendicular to the direction of movement, thereby improving the accuracy of the four-way optical path interferometer.

[0077] In one embodiment, the material of the beam splitter 11 includes any one of calcium fluoride (CaF2), potassium bromide (KBr), and zinc selenide (ZnSe); and / or,

[0078] The detector 18 includes any one of the following: mercury cadmium telluride (MCT) detector 18, indium antimonide (InSb) detector 18, lead selenide (PbSe) detector 18, DTGS detector 18, and indium gallium arsenide (InGaAs) detector 18.

[0079] Among them, the DTGS detector 18 is an infrared detector made using the temperature-dependent polarization characteristic of triglycine sulfate crystal (TGS), which is called DTGS after deuteration treatment. The surfaces of the various reflectors mentioned above may or may not be coated. The wavelength range of the light source is between 300 nm and 20 μm.

[0080] Figure 4 and Figure 5 A four-way optical path interferometer is provided for another embodiment of this application. The interferometer includes: a semi-reflective and semi-transparent beam splitter 21, a first single-sided total reflection mirror 22, a second single-sided total reflection mirror 23, a first target reflection mirror 24, a second target reflection mirror 25, a linear displacement platform 26, and a detector 27. The first target reflection mirror 24 and the second target reflection mirror 25 are both reflection mirrors that can reflect all light.

[0081] The first single-sided total reflection mirror 22 and the second single-sided total reflection mirror 23 are respectively tilted on the linear displacement platform 26, and the first single-sided total reflection mirror 22 and the second single-sided total reflection mirror 23 are perpendicular to each other.

[0082] The first single-sided total reflection mirror 22 and the detector 27 are located on both sides of the beam splitter 21, and the center points of the first single-sided total reflection mirror 22, the detector 27 and the beam splitter 21 are on the same straight line. The first single-sided reflection mirror is parallel to the beam splitter 21.

[0083] The second target reflector 25 is perpendicular to the moving direction of the linear displacement platform 26, the center lines of the beam splitter 21 and the first target reflector 24 are on the same straight line, and the first target reflector 24 is located between the linear displacement platform 26 and the second target reflector 25.

[0084] Among them, such as Figure 4 As shown, after the light source enters the beam splitter 21 perpendicular to the direction of movement, it is split into a reflected beam path and a transmitted beam path. The reflected beam path passes sequentially through the first single-sided total internal reflection mirror 22, the second single-sided total internal reflection mirror 23, and the second target mirror 25, and is reflected back to the beam splitter 21 along the original path. The transmitted beam path passes sequentially through the first target mirror 24 and the second target mirror 25, and is reflected back to the beam splitter 21 along the original path. Or, as... Figure 5 As shown, the transmitted beam passes only through the first target reflector 24 in the optical path and is reflected back to the beam splitter 21 along the original path. Finally, the light rays from the two optical paths interfere and reach the detector 27.

[0085] The distance between the center point of the beam splitter 21 and the center point of the first target reflector 24 is such that the optical path difference between the reflected beam path and the transmitted beam path is four times the moving distance of the first single-sided total reflection mirror 22 or the second single-sided total reflection mirror 23.

[0086] This invention provides a four-times optical path interferometer. By introducing two movable, mutually perpendicularly placed single-sided total internal reflection mirrors, the optical path of the reflected beam includes a four-times moving distance. Furthermore, by setting the positions and distances of the first and second target mirrors, the optical path difference between the reflected and transmitted beams cancels out at other distances, retaining only the four-times moving distance, thus achieving a four-times optical path interferometer. Compared to a traditional Michelson interferometer, to achieve the same optical path difference, the moving distance of the interferometer in this embodiment is 1 / 4 of the optical path difference, which is 1 / 2 of the moving distance of the Michelson interferometer. This indicates that, when applied to FTIR, the interferometer of this embodiment can achieve twice the spectral resolution of the Michelson interferometer with the same moving mirror moving distance. Moreover, the reduced moving distance also helps to reduce the volume of the linear displacement stage and miniaturize the overall structure.

[0087] In one possible implementation, such as Figure 4 As shown, when the first target reflector 24 is parallel to the second single-sided total reflection mirror 23, the transmitted beam passes through the first target reflector 24 and the second target reflector 25 in sequence on the optical path, and the distance between the center point of the beam splitter 21 and the center point of the first target reflector 24 is the sum of the third distance and twice the first distance.

[0088] The first distance is the initial distance between the center point of the beam splitter 21 and the center point of the first single-sided total reflection mirror 22;

[0089] The third distance is the distance between the center point of the first single-sided total reflection mirror 22 and the center point of the second single-sided total reflection mirror 23.

[0090] like Figure 4 As shown, if the first distance is represented by d1, the second distance by d2, the third distance by d3, and the moving distance of the linear displacement platform 26 by d, then the distance between the first single-sided total reflection mirror 22 and the beam splitter 21 is d+d1, the distance between the second single-sided total reflection mirror 23 and the second target reflector 25 is d+d1+d2, and the distance between the beam splitter 21 and the first target reflector 24 is 2d1+d3. The optical path length of the reflected beam is 4d1+2d2+2d3+4d, the optical path length of the transmitted beam is 4d1+2d2+2d3, and the optical path difference between the two is D=4d.

[0091] In one possible implementation, such as Figure 5 As shown, when the first target reflector 24 is perpendicular to the second target reflector 25, the transmitted beam only passes through the first target reflector 24 in the optical path, and the distance between the center point of the beam splitter 21 and the center point of the first target reflector 24 is 2*first distance + second distance + third distance.

[0092] The first distance is the initial distance between the center point of the beam splitter 21 and the center point of the first single-sided total reflection mirror 22;

[0093] The second distance is the vertical distance from the center point of the first target reflector 24 to the second target reflector 25;

[0094] The third distance is the distance between the center point of the first single-sided total reflection mirror 22 and the center point of the second single-sided total reflection mirror 23.

[0095] In one possible implementation, the first target reflector 24 is a corner reflector or a single-sided total reflection mirror, and / or the second target reflector 25 is a corner reflector or a single-sided total reflection mirror.

[0096] like Figure 5 As shown, if the first distance is represented by d1, the second distance by d2, the third distance by d3, and the moving distance of the linear displacement platform 26 by d, then the distance between the first single-sided total reflection mirror 22 and the beam splitter 21 is d+d1, the distance between the second single-sided total reflection mirror 23 and the second target reflector 25 is d+d1+d2, and the distance between the beam splitter 21 and the first target reflector 24 is 2d1+d2+d3. The optical path length of the reflected beam is 4d1+2d2+2d3+4d, the optical path length of the transmitted beam is 4d1+2d2+2d3, and the optical path difference between the two is D=4d.

[0097] In one possible implementation, the beam splitter 21, the first single-sided total reflection mirror 22, and the second single-sided total reflection mirror 23 are tilted at 45 degrees.

[0098] When the tilt angle of the beam splitter 21, the first single-sided total reflection mirror 22, and the second single-sided total reflection mirror 23 is 45 degrees, it can be ensured that the optical paths of the reflected beam and the transmitted beam only include two types of light rays: those parallel to the direction of movement and those perpendicular to the direction of movement, thereby improving the accuracy of the four-times optical path interferometer.

[0099] In one possible implementation, the material of the beam splitter 21 includes any one of calcium fluoride, potassium bromide, and zinc selenide; and / or,

[0100] The detector 27 includes any one of the following: mercury cadmium telluride detector 27, indium antimonide detector 27, lead selenide detector 27, DTGS detector 27, and indium gallium arsenide detector 27.

[0101] Those skilled in the art will understand that the accompanying drawings are merely schematic diagrams of one embodiment, and the modules or processes shown in the drawings are not necessarily essential for implementing this application.

[0102] Those skilled in the art will understand that the modules in the apparatus of the embodiments can be distributed in the apparatus of the embodiments as described in the embodiments, or they can be located in one or more devices different from this embodiment with corresponding changes. The modules of the above embodiments can be combined into one module, or they can be further divided into multiple sub-modules.

[0103] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A quadruple optical path interferometer, characterized in that, The interferometer comprises a half-reflective half-transmissive beam splitter, a first single-surface total reflector, a second single-surface total reflector, a first target reflector, a second target reflector, a double-surface total reflector, a linear displacement platform, and a detector, wherein the first target reflector and the second target reflector are both totally reflective reflectors; The first single-surface total reflector and the second single-surface total reflector are both arranged on the linear displacement platform in a tilted manner, and the first single-surface total reflector and the second single-surface total reflector are perpendicular to each other; The first single-surface total reflector and the detector are both located on the two sides of the beam splitter, and the center points of the first single-surface total reflector, the detector, and the beam splitter are on the same straight line, and the first single-surface total reflector is parallel to the beam splitter; The second single-surface total reflector and the second target reflector are both located on the two sides of the double-surface total reflector, and the center points of the second single-surface total reflector, the second target reflector, and the double-surface total reflector are on the same straight line, and the second target reflector is perpendicular to the moving direction of the linear displacement platform, and the second single-surface total reflector is parallel to the double-surface total reflector; The beam splitter and the first target reflector are both located on the two sides of the double-surface total reflector, and the center points of the beam splitter, the first target reflector, and the double-surface total reflector are on the same straight line, and the first target reflector is parallel to the moving direction of the linear displacement platform; When the initial distance between the center point of the double-surface total reflector and the center point of the second single-surface total reflector is a first distance, and the vertical distance from the center point of the double-surface total reflector to the first target reflector is a second distance, the vertical distance from the center point of the double-surface total reflector to the second target reflector is the sum of the second distance and twice the first distance. After the light source is incident on the beam splitter perpendicularly to the moving direction, the light is divided into a reflected beam light path and a transmitted beam light path, the reflected beam light path sequentially passes through the first single-surface total reflector, the second single-surface total reflector, the double-surface total reflector, and the first target reflector, and is reflected back to the beam splitter along the original path, the transmitted beam light path sequentially passes through the double-surface total reflector and the second target reflector, and is reflected back to the beam splitter along the original path, and the light on the two light paths reaches the detector through interference.

2. The quadruple optical path interferometer according to claim 1, characterized in that The first target reflector is a corner reflector or a single-surface total reflector, and / or the second target reflector is a corner reflector or a single-surface total reflector.

3. The quadruple optical path interferometer of claim 1, wherein, The inclination angles of the beam splitter, the first single-surface total reflector, the second single-surface total reflector, and the double-surface total reflector are all 45 degrees.

4. The quadruple optical path interferometer according to any one of claims 1-3, characterized in that, The material of the beam splitter comprises any one of calcium fluoride, potassium bromide, and zinc selenide; and / or, The detector comprises any one of a mercury cadmium telluride detector, an indium antimonide detector, a lead selenide detector, a DTGS detector, and an indium gallium arsenide detector.

5. A quadruple optical path interferometer characterized in that, The interferometer comprises a half-reflecting half-transmitting beam splitter, a first single-face total reflection mirror, a second single-face total reflection mirror, a first target mirror, a second target mirror, a linear displacement platform and a detector, and the first target mirror and the second target mirror are both mirrors capable of totally reflecting light; The first single-face total reflection mirror and the second single-face total reflection mirror are respectively arranged in a tilted manner on the linear displacement platform, and the first single-face total reflection mirror and the second single-face total reflection mirror are perpendicular to each other; The first single-face total reflection mirror and the detector are respectively located on two sides of the beam splitter, and the center point of the first single-face total reflection mirror, the detector and the beam splitter are on the same straight line, and the first single-face mirror is parallel to the beam splitter; The second target mirror is perpendicular to the moving direction of the linear displacement platform, the center line of the beam splitter and the first target mirror are on the same straight line, and the first target mirror is located between the linear displacement platform and the second target mirror; After the light source is incident into the beam splitter perpendicularly to the moving direction, the light is divided into a reflected beam light path and a transmitted beam light path, the reflected beam light path sequentially passes through the first single-face total reflection mirror, the second single-face total reflection mirror and the second target mirror, and is reflected back to the beam splitter along the original path, the transmitted beam light path sequentially passes through the first target mirror and the second target mirror, and is reflected back to the beam splitter along the original path, or the transmitted beam light path only passes through the first target mirror, and is reflected back to the beam splitter along the original path, and the light of the last two light paths reaches the detector through interference; The distance between the center point of the beam splitter and the center point of the first target mirror can make the optical path difference of the reflected beam light path and the transmitted beam light path be four times the moving distance of the first single-face total reflection mirror or the second single-face total reflection mirror.

6. The quadruple optical path interferometer according to claim 5, characterized in that When the first target mirror is parallel to the second single-face total reflection mirror, the transmitted beam light path sequentially passes through the first target mirror and the second target mirror, and the distance between the center point of the beam splitter and the center point of the first target mirror is the sum of a second distance and twice a first distance; The first distance is the initial distance between the center point of the beam splitter and the center point of the first single-face total reflection mirror; The second distance is the distance between the center point of the first single-face total reflection mirror and the center point of the second single-face total reflection mirror.

7. The quadruple optical path interferometer according to claim 5, characterized in that When the first target mirror is perpendicular to the second target mirror, the transmitted beam light path only passes through the first target mirror, and the distance between the center point of the beam splitter and the center point of the first target mirror is 2*first distance+second distance+third distance; The first distance is the initial distance between the center point of the beam splitter and the center point of the first single-face total reflection mirror; The second distance is the distance between the center point of the first single-face total reflection mirror and the center point of the second single-face total reflection mirror; The third distance is the distance between the center point of the first target mirror and the center point of the second target mirror. The third distance is the vertical distance from the center point of the first target mirror to the second target mirror.

8. The quadruple optical path interferometer of claim 5, wherein, The first target mirror is a corner cube mirror or a single surface total reflection mirror, and / or the second target mirror is a corner cube mirror or a single surface total reflection mirror.

9. The quadruple optical path interferometer of claim 5, wherein, The inclination angles of the beam splitter, the first single surface total reflection mirror and the second single surface total reflection mirror are 45 degrees respectively.

10. The quadruple optical path interferometer according to any one of claims 5-9, characterized in that, The material of the beam splitter comprises any one of calcium fluoride, potassium bromide and zinc selenide; and / or, The detector comprises any one of a mercury cadmium telluride detector, an indium antimonide detector, a lead selenide detector, a DTGS detector and an indium gallium arsenide detector.

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