A dual-band Fourier transform spectrometer

Abstract

The application discloses a double-waveband Fourier transform spectrometer, and relates to the technical field of spectrometers. The spectrometer comprises a first Michelson interference optical path assembly and a second Michelson interference optical path assembly. The first Michelson interference optical path and the second Michelson optical path use the front and back surfaces of a same moving mirror as phase modulators. The coating materials of the front and back surfaces of the moving mirror are different. The reflected light beams of the front and back surfaces of the moving mirror have different wavebands. The application improves the signal quality of the spectrometer when detecting wavebands or measuring across wavebands through the double-path Michelson interference optical path assembly of the shared moving mirror.

Description

Technical Field

[0001] This application relates to the field of spectrometer technology, and in particular to a dual-band Fourier transform spectrometer. Background Technology

[0002] Fourier transform spectrometers are widely used in spectral analysis because of their high light throughput and lack of interference from stray light generated by dispersive devices, while also being able to produce full-spectrum spectra without the need for array detectors. However, their high hardware costs, especially the core component, the vertically shifted phase modulation mirror, limit their application to scientific research. Fourier transform spectrometers typically cover the mid-infrared range of 2500nm-10000nm or the near-infrared range of 1000-2500nm. Limited by optical and detector material constraints, the detection range cannot be further expanded. The current spectrometer market favors multi-band joint analysis, with near-infrared-visible spectral joint modeling analysis receiving increasing attention. Currently, wide-band spectrometers on the market are constructed by stitching together multiple spectrometers, resulting in high hardware costs. Furthermore, inconsistencies in optical paths and acquisition times between different spectrometers lead to inconsistent data, severely impacting the accuracy of modeling data. Therefore, there is an urgent need to develop a Fourier transform spectrometer with lower hardware costs that can achieve wide-band and cross-band coverage. Summary of the Invention

[0003] The purpose of this application is to provide a dual-band Fourier transform spectrometer that can improve signal quality during wide-band or cross-band measurements.

[0004] To achieve the above objectives, this application provides the following solution: This application provides a dual-band Fourier transform spectrometer, including a first Michelson interferometer optical path assembly and a second Michelson interferometer optical path assembly sharing a common moving mirror; The first sample light enters the first Michelson interferometer optical path component for beam splitting, interference and phase modulation, and outputs the first interference beam to the first detector; The second sample light enters the second Michelson interferometer optical path component for beam splitting, interference and phase modulation, and outputs the second interference beam to the second detector; The coating materials on the front and back sides of the moving mirror are different; The wavelengths of the output beams reflected by the different coating materials on the front and back of the moving mirror are different; The front or back of the moving mirror is the phase modulator of the first Michelson interference optical path component; The reverse or front side of the moving mirror is the phase modulator of the first Michelson interference optical path component.

[0005] Optionally, the moving mirror is a MEMS moving mirror or a motor-driven mechanical moving mirror; the MEMS moving mirror is an electrothermal MEMS, electromagnetic MEMS, piezoelectric MEMS or electrostatic MEMS.

[0006] Optionally, when the coating material of the reflective surface of the moving mirror is gold, the light beam reflected and output by the reflective surface of the moving mirror can be near-infrared light; the reflective surface is the front or back of the moving mirror. When the coating material of the reflective surface of the moving mirror is aluminum, the light beam output after reflection by the reflective surface of the moving mirror can be ultraviolet light; the reflective surface is the front or back of the moving mirror.

[0007] Optionally, the first Michelson interferometer assembly includes: a first beam splitter and a first fixing lens; The second Michelson interferometer assembly includes: a second beam splitter and a second fixed mirror; The first detector, the first beam splitter, the moving mirror, the second beam splitter, and the second detector are arranged along a first straight line; The first beam splitter and the first fixed mirror are arranged along the second straight line; The second beam splitter and the second fixed mirror are arranged along a third straight line; Both the second and third lines are perpendicular to the first line; The first sample light enters the first Michelson interferometer optical path assembly, is split by the first beam splitter to the first fixed mirror and the moving mirror, and after reflection, returns to the first beam splitter and is combined into the first interference beam, which is then output to the first detector. The second sample light enters the second Michelson interferometer optical path assembly, is split by the second beam splitter to the second fixed mirror and the moving mirror, and after reflection, returns to the second beam splitter and is combined into the second interference beam, which is then output to the second detector. The moving mirror is moved along the first straight line to change the phase difference between the two beams after the first beam splitter splits the beam, thereby achieving phase modulation; at the same time, the phase difference between the two beams after the second beam splitter splits the beam is also changed to achieve phase modulation.

[0008] Optionally, the dual-band Fourier transform spectrometer further includes: Spectral sample beam splitter input device; The spectral sample beam splitter input device is disposed on the input optical path of the first Michelson interferometer and the second Michelson interferometer; The spectral sample light beam splitting input device is used to split the sample light into a first sample light and a second sample light.

[0009] Optionally, the spectral sample beam splitter input device includes: Dichroic mirrors and reflecting mirrors; The dichroic mirror is disposed in the input optical path of the first Michelson interferometer; the dichroic mirror is disposed in the input optical path of the reflector; the reflector is disposed in the input optical path of the second Michelson interferometer. The dichroic mirror is used to split the sample light into a first sample light and a second sample light, and outputs the first sample light and the second sample light to the first Michelson interferometer component, and outputs the second sample light to the reflector. The mirror is used to reflect the second sample light to the second Michelson interferometer.

[0010] Optionally, the spectral sample beam splitter input device is a Y-type optical fiber; The Y-shaped optical fiber is used to output a first sample light to the first Michelson interferometer and a second sample light to the second Michelson interferometer.

[0011] Optionally, the spectral sample beam splitter input device includes: First optical fiber and second optical fiber; The first optical fiber is used to output the first sample light to the first Michelson interferometer assembly; The second optical fiber is used to output the second sample light to the second Michelson interferometer.

[0012] According to the specific embodiments provided in this application, the following technical effects are disclosed: This application provides a dual-band Fourier transform spectrometer in which the first and second Michelson interferometers in the dual-path Michelson interferometer optical path assembly share the moving mirror, effectively increasing the value of one spectrometer to that of two, thereby reducing hardware technology costs.

[0013] Furthermore, this application utilizes a dichroic mirror to split broadband light into two beams with different wavelengths, achieving lossless spectral splitting to ensure luminous flux at each wavelength without reducing the signal-to-noise ratio. This application can cover a wide spectral range, and the combined analysis of the two spectral bands can achieve a synergistic effect (1+1>2). Simultaneously, because this spectrometer does not involve switching optical paths during spectrum output (compared to commercially available broadband spectrometers which are almost entirely composed of multiple spliced ​​spectrometers), it achieves simultaneous acquisition of dual-band spectra in a single operation, possessing high application and research value. The spectral information from the two spectral bands acquired using this integrated device exhibits high consistency, avoiding data errors caused by inconsistent acquisition times and optical paths in spliced ​​spectrometers. Current optical and optoelectronic materials are selective for light wavelengths, meaning signal quality varies depending on the wavelength; no single device or material can cover the entire spectrum with high quality. Therefore, this type of dual-band spectrometer can flexibly select the cutoff wavelength according to the target spectral band, and the two interferometers can select specific optical components, enabling high-quality signals to be obtained in both bands. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of the dual-band Fourier transform spectrometer structure in the embodiments of this application.

[0016] Figure 2 This is a schematic diagram of the dual-band Fourier transform spectrometer structure in Embodiment 1 of this application.

[0017] Figure 3 This is a schematic diagram of the dual-band Fourier transform spectrometer structure in Embodiment 2 of this application.

[0018] Figure 4 This is a schematic diagram of the dual-band Fourier transform spectrometer structure in Embodiment 3 of this application.

[0019] Figure 5 This is a schematic diagram of the dual-band Fourier transform spectrometer structure in Embodiment 4 of this application.

[0020] Figure 6 This is a schematic diagram of the dual-band Fourier transform spectrometer structure in Embodiment 5 of this application.

[0021] Figure reference numerals: 1-First detector; 2-First beam splitter; 3-First fixed mirror; 4-Moving mirror; 5-Second beam splitter; 6-Second detector; 7-Second fixed mirror. Detailed Implementation

[0022] 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 some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0023] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] Example 1 like Figure 1 and Figure 2This embodiment provides a dual-band Fourier transform spectrometer, including a first Michelson interferometer optical path assembly and a second Michelson interferometer optical path assembly sharing a moving mirror 4; a first sample light enters the first Michelson interferometer optical path assembly for beam splitting, interference, and phase modulation, and outputs a first interference beam to a first detector 1; a second sample light enters the second Michelson interferometer optical path assembly for beam splitting, interference, and phase modulation, and outputs a second interference beam to a second detector 7; the front and back surfaces of the moving mirror have different coating materials; the output beams reflected by the different coating materials on the front and back surfaces of the moving mirror have different wavelengths; the front or back surface of the moving mirror is a phase modulator of the first Michelson interferometer optical path assembly; the back or front surface of the moving mirror is a phase modulator of the first Michelson interferometer optical path assembly.

[0025] The moving mirror is a MEMS moving mirror, which can be an electrothermal MEMS, electromagnetic MEMS, piezoelectric MEMS or electrostatic MEMS.

[0026] When the coating material of the reflecting surface of the moving mirror is gold, the light beam reflected from the reflecting surface can be near-infrared light; the reflecting surface can be either the front or back of the moving mirror. When the coating material of the reflecting surface of the moving mirror is aluminum, the light beam reflected from the reflecting surface can be ultraviolet light; the reflecting surface can also be either the front or back of the moving mirror. Correspondingly, other optical components of the Michelson interferometer optical paths for the first and second bands also need to be adapted according to the optical requirements of the dual-band system. The correspondence between the coating materials of the front and back surfaces of the moving mirror and the corresponding bands is shown in Table 1.

[0027] Table 1. Reflection bands and reflectivity of the coating material for the moving mirror

[0028] In practical applications, reflectivity can vary due to factors such as coating thickness, substrate material, and incident angle. Certain materials (such as SiO2, TiO2, and MgF2) are commonly used in antireflection coatings; therefore, the table shows reflectivity or transmittance in typical applications. Multilayer dielectric films can be designed to have very high reflectivity (>99%) in specific wavelength bands, but this design is specific to a particular application.

[0029] The first Michelson interferometer assembly includes a first beam splitter 2 and a first fixed mirror 3; the second Michelson interferometer assembly includes a second beam splitter 5 and a second fixed mirror 6; a first detector, a first beam splitter, a moving mirror, a second beam splitter, and a second detector are arranged along a first straight line; the first beam splitter and the first fixed mirror are arranged along a second straight line; the second beam splitter and the second fixed mirror are arranged along a third straight line; both the second and third straight lines are perpendicular to the first straight line; a first sample light enters the first Michelson interferometer optical path assembly, is split by the first beam splitter to the first fixed mirror and the moving mirror, and after reflection, returns to the first beam splitter and is combined into a first interference beam, which is then output to the first detector; a second sample light enters the second Michelson interferometer optical path assembly, is split by the second beam splitter to the second fixed mirror and the moving mirror, and after reflection, returns to the second beam splitter and is combined into a second interference beam, which is then output to the second detector; moving the moving mirror along the first straight line changes the phase difference between the two beams after splitting by the first beam splitter to achieve phase modulation; simultaneously changing the phase difference between the two beams after splitting by the second beam splitter also achieves phase modulation.

[0030] The first Michelson interferometer optical path assembly may include other collimating, focusing, or other auxiliary lenses to improve interference efficiency or for other applications.

[0031] In addition, the dual-band Fourier transform spectrometer also includes: a spectral sample light beam splitting input device; the spectral sample light beam splitting input device is disposed on the input optical path of the first Michelson interferometer and the second Michelson interferometer; the spectral sample light beam splitting input device is used to split the sample light into the first sample light and the second sample light.

[0032] Specifically, the spectral sample light beam splitting input device includes: a dichroic mirror and a reflector; the dichroic mirror is disposed in the input light path of the first Michelson interferometer; the dichroic mirror is disposed in the input light path of the reflector; the reflector is disposed in the input light path of the second Michelson interferometer; the dichroic mirror is used to split the sample light into a first sample light and a second sample light, outputting the first sample light and the second sample light to the first Michelson interferometer, and outputting the second sample light to the reflector; the reflector is used to reflect the second sample light to the second Michelson interferometer.

[0033] like Figure 2As shown, the dual-band Fourier transform spectrometer comprises two axisymmetric Michelson interferometers, which are organically combined with dichroic mirrors and reflecting mirrors to analyze synchronous broadband spectra. The sample broadband light first reaches the dichroic mirror. Light in band 1 passes through the dichroic mirror and enters the upper Michelson interferometer path, while light in band 2 is reflected by the dichroic mirror to the lower reflecting mirror, and then reflected again to enter the lower Michelson interferometer path parallel to the sample light. The Michelson interferometer path splits the incoming light into two beams by a beam splitter: one beam passes through the beam splitter to the fixed mirror, which then reflects it back to the beam splitter; the other beam is reflected by the beam splitter to the moving mirror, which then reflects it back to the beam splitter. These two beams are combined by the beam splitter and reach the detection system, where they interfere. Because the position of the moving mirror causes an optical path difference between the two beams, phase modulation can be achieved by controlling the moving mirror, thus realizing a Fourier transform analytical spectrum.

[0034] Example 2 This embodiment provides a dual-band Fourier transform spectrometer, such as... Figure 3 The difference between this embodiment and embodiment 1 is that the moving mirror in this embodiment is a mechanical moving mirror driven by a motor.

[0035] Furthermore, the moving mirror can be a vertically large-displacement MEMS micromirror, a traditional moving mirror, or a MEMS micromirror. By adjusting the materials on the front and back of the moving mirror, cross-spectral spectrometers such as UV-Vis / NIR, UV-Vis / Mid-Infrared, NIR / Mid-Infrared, and Mid-Infrared / Far-Infrared can be achieved, which has high application value, especially UV-Vis / NIR dual-band spectrometers. Certain specific scenarios have clear requirements for spectrometers with specific band combinations. This application, through an innovative dual-band Fourier transform spectrometer with a shared moving mirror, truly improves the detection signal range (segmented spectrometers on the market suffer from spectral asynchrony issues, which greatly limits many scenarios requiring modeling), indirectly reducing hardware costs and showing broad application prospects.

[0036] Example 3 This embodiment provides a dual-band Fourier transform spectrometer, such as... Figure 4 The difference between this embodiment and embodiment 1 is that the spectral sample light beam splitting input device in this embodiment is a Y-type optical fiber; the Y-type optical fiber is used to output the first sample light to the first Michelson interferometer component and the second sample light to the second Michelson interferometer component.

[0037] Example 4 This embodiment provides a dual-band Fourier transform spectrometer, such as... Figure 5The difference between this embodiment and embodiment 1 is that the spectral sample light beam splitting input device in this embodiment includes: a first optical fiber and a second optical fiber; the first optical fiber is used to output the first sample light to the first Michelson interferometer component; and the second optical fiber is used to output the second sample light to the second Michelson interferometer component.

[0038] Example 5 This embodiment provides a dual-band Fourier transform spectrometer, such as... Figure 6 The difference between this embodiment and embodiment 1 is that the spectral sample beam splitting input device in this embodiment uses other waveguide methods.

[0039] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A dual band Fourier transform spectrometer, characterized by, Including the first Michelson interferometer optical path assembly and the second Michelson interferometer optical path assembly that share a moving mirror; The first sample light enters the first Michelson interferometer optical path component for beam splitting, interference and phase modulation, and outputs the first interference beam to the first detector; The second sample light enters the second Michelson interferometer optical path component for beam splitting, interference and phase modulation, and outputs the second interference beam to the second detector; The coating materials on the front and back sides of the moving mirror are different; The wavelengths of the output beams reflected by the different coating materials on the front and back of the moving mirror are different; The front or back of the moving mirror is the phase modulator of the first Michelson interference optical path component; The reverse or front side of the moving mirror is the phase modulator of the first Michelson interference optical path component.

2. The dual-band Fourier transform spectrometer according to claim 1, characterized in that, The moving mirror is a MEMS moving mirror or a motor-driven mechanical moving mirror; the MEMS moving mirror is an electrothermal MEMS, electromagnetic MEMS, piezoelectric MEMS or electrostatic MEMS.

3. The dual-band Fourier transform spectrometer according to claim 1, characterized in that, When the coating material of the reflective surface of the moving mirror is gold, the light beam reflected and output by the reflective surface of the moving mirror can be near-infrared light; the reflective surface can be the front or back of the moving mirror. When the coating material of the reflective surface of the moving mirror is aluminum, the light beam output after reflection by the reflective surface of the moving mirror can be ultraviolet light; the reflective surface is the front or back of the moving mirror.

4. The dual-band Fourier transform spectrometer according to claim 1, characterized in that, The first Michelson interferometer assembly includes: a first beam splitter and a first fixed mirror; The second Michelson interferometer assembly includes: a second beam splitter and a second fixed mirror; The first detector, the first beam splitter, the moving mirror, the second beam splitter, and the second detector are arranged along a first straight line; The first beam splitter and the first fixed mirror are arranged along the second straight line; The second beam splitter and the second fixed mirror are arranged along a third straight line; Both the second and third lines are perpendicular to the first line; The first sample light enters the first Michelson interferometer optical path assembly, is split by the first beam splitter to the first fixed mirror and the moving mirror, and after reflection, returns to the first beam splitter and is combined into the first interference beam, which is then output to the first detector. The second sample light enters the second Michelson interferometer optical path assembly, is split by the second beam splitter to the second fixed mirror and the moving mirror, and after reflection, returns to the second beam splitter and is combined into the second interference beam, which is then output to the second detector. The moving mirror is moved along the first straight line to change the phase difference between the two beams after the first beam splitter splits the beam, thereby achieving phase modulation; at the same time, the phase difference between the two beams after the second beam splitter splits the beam is also changed to achieve phase modulation.

5. The dual-band Fourier transform spectrometer according to claim 1, characterized in that, The dual-band Fourier transform spectrometer also includes: Spectral sample beam splitter input device; The spectral sample beam splitter input device is disposed on the input optical path of the first Michelson interferometer and the second Michelson interferometer; The spectral sample light beam splitting input device is used to split the sample light into a first sample light and a second sample light.

6. The dual-band Fourier transform spectrometer according to claim 5, characterized in that, The spectral sample beam splitter input device includes: Dichroic mirrors and reflecting mirrors; The dichroic mirror is disposed in the input optical path of the first Michelson interferometer; the dichroic mirror is disposed in the input optical path of the reflector; the reflector is disposed in the input optical path of the second Michelson interferometer. The dichroic mirror is used to split the sample light into a first sample light and a second sample light, and outputs the first sample light and the second sample light to the first Michelson interferometer component, and outputs the second sample light to the reflector. The mirror is used to reflect the second sample light to the second Michelson interferometer.

7. The dual-band Fourier transform spectrometer according to claim 5, characterized in that, The optical beam splitter input device for the spectral sample is a Y-type optical fiber; The Y-shaped optical fiber is used to output a first sample light to the first Michelson interferometer and a second sample light to the second Michelson interferometer.

8. The dual-band Fourier transform spectrometer according to claim 5, characterized in that, The spectral sample beam splitter input device includes: First optical fiber and second optical fiber; The first optical fiber is used to output the first sample light to the first Michelson interferometer assembly; The second optical fiber is used to output the second sample light to the second Michelson interferometer.

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