Raman spectrometer

Abstract

This Raman spectroscopy device (1) comprises a first light disperser (44), a second light disperser (46), and a photodetector (50). The first light disperser (44) disperses first Raman scattered light (31). The second light disperser (46) disperses second Raman scattered light (33) having a shorter wavelength than the first Raman scattered light (31). The photodetector (50) receives first Raman scattered light (31) and second Raman scattered light (33). The second light disperser (46) is configured from more dispersion optical elements than the first light disperser (44).

Description

Technical Field

[0001] The present disclosure relates to a Raman spectrometer.

Background Art

[0002] U.S. Patent No. 8,873,041 (Patent Document 1) discloses a Raman spectrometer using two excitation wavelengths.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present disclosure is to provide a Raman spectrometer that can expand the measurement frequency range of a Raman spectrum for Raman scattered light emitted from a sample by irradiating the sample with an excitation light beam having a shorter wavelength among a plurality of excitation wavelengths and that has a reduced cost.

Means for Solving the Problems

[0005] The Raman spectrometer of the present disclosure includes a spectroscopic optical system and a photodetector. The spectroscopic optical system includes a first spectroscope and a second spectroscope. The first spectroscope spectroscopically analyzes first Raman scattered light emitted from a sample when the sample is irradiated with a first excitation light beam. The second spectroscope spectroscopically analyzes second Raman scattered light that is emitted from the sample when the sample is irradiated with a second excitation light beam having a wavelength shorter than that of the first excitation light beam and that has a wavelength shorter than that of the first Raman scattered light. The photodetector receives the first Raman scattered light and the second Raman scattered light output from the spectroscopic optical system. A second incident optical path of the second Raman scattered light to the second spectroscope in the spectroscopic optical system is different from a first incident optical path of the first Raman scattered light to the first spectroscope in the spectroscopic optical system. The second spectroscope is composed of a larger number of spectroscopic optical elements than the first spectroscope.

Advantages of the Invention

[0006] The Raman spectrometer of the present disclosure can expand the measurement frequency range of the Raman spectrum for second Raman scattered light emitted from a sample by irradiating the sample with a second excitation light beam having a wavelength shorter than that of the first excitation light beam, and has a reduced cost.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0008] Hereinafter, embodiments of the present disclosure will be described. The same components are denoted by the same reference numerals, and the description thereof will not be repeated.

[0009] Referring to FIGS. 1 and 2, the Raman spectrometer 1 of the embodiment will be described. The Raman spectrometer 1 includes a first excitation light source 10, a second excitation light source 12, a sample support portion 25a, a spectroscopic optical system 40, a photodetector 50, a signal processor 55, mirrors 15, 16, 19, 21, 22, 26, low-pass filters 17, 18, a dichroic mirror 20, condenser lenses 27, 28, and slits 29, 30. The Raman spectrometer 1 may further include an illumination light source 60, an objective lens 24, a half mirror 23, an imaging lens 62, and a camera 63.

[0010] The first excitation light source 10 outputs a first excitation light beam 11. The second excitation light source 12 outputs a second excitation light beam 13 having a wavelength shorter than that of the first excitation light beam 11. The first wavelength of the first excitation light beam 11 may differ from the second wavelength of the second excitation light beam 13 by 40 nm or more, 100 nm or more, or 200 nm or more. In one example, the first wavelength of the first excitation light beam 11 is 785 nm, and the second wavelength of the second excitation light beam 13 is 532 nm. In another example, the first wavelength of the first excitation light beam 11 is 1064 nm, and the second wavelength of the second excitation light beam 13 is 532 nm. The first excitation light source 10 and the second excitation light source 12 are, for example, laser light sources, and the first excitation light beam 11 and the second excitation light beam 13 are, for example, laser beams. The first excitation light source 10 and the second excitation light source 12 are, for example, diode laser-excited solid-state lasers, helium-neon lasers, titanium-sapphire lasers, or Nd:YAG lasers.

[0011] The sample 25 is supported by a sample support part 25a such as a sample stage. Depending on the sample 25, either one of the first excitation light beam 11 and the second excitation light beam 13 is irradiated onto the sample 25. The shorter the excitation wavelength, the higher the efficiency of Raman scattering. Therefore, when increasing the intensity of the Raman scattered light, the sample 25 is irradiated with the second excitation light beam 13 instead of the first excitation light beam 11. If the sample 25 emits strong fluorescence when irradiated with the second excitation light beam 13, the sample 25 is irradiated with the first excitation light beam 11 instead of the second excitation light beam 13. Therefore, the Raman spectrum of the sample 25 can be obtained without being affected by fluorescence.

[0012] The first excitation light beam 11 output from the first excitation light source 10 is reflected by the mirrors 15 and 16 and enters the low-pass filter 17. The low-pass filter 17 reflects the first excitation light beam 11 and transmits the first Raman scattered light 31. The first excitation light beam 11 is reflected by the low-pass filter 17 and enters the dichroic mirror 20. The dichroic mirror 20 transmits the first excitation light beam 11 and the first Raman scattered light 31 and reflects the second excitation light beam 13 and the second Raman scattered light 33. The first excitation light beam 11 passes through the dichroic mirror 20. The first excitation light beam 11 is reflected by the mirrors 21 and 22. The first excitation light beam 11 is irradiated onto the sample 25 through the half mirror 23 and the objective lens 24.

[0013] The second excitation light beam 13 output from the second excitation light source 12 is reflected by the mirrors 15 and 16 and enters the low-pass filter 18. The low-pass filter 18 reflects the second excitation light beam 13 and transmits the second Raman scattered light 33. The second excitation light beam 13 is reflected by the low-pass filter 18, the mirror 19, and the dichroic mirror 20. The second excitation light beam 13 is reflected by the mirrors 21 and 22. The second excitation light beam 13 is irradiated onto the sample 25 through the half mirror 23 and the objective lens 24.

[0014] When the sample 25 is irradiated with the first excitation light beam 11, the first Raman scattered light 31 is emitted from the sample 25. The first Raman scattered light 31 has a wavelength longer than that of the first excitation light beam 11. The first Raman scattered light 31 is reflected by the mirrors 21 and 22 through the objective lens 24 and the half mirror 23. The first Raman scattered light 31 passes through the dichroic mirror 20 and the low-pass filter 17 and is reflected by the mirror 26. The first Raman scattered light 31 is condensed by the condenser lens 27, passes through the slit 29, and enters the spectroscopic optical system 40.

[0015] When the sample 25 is irradiated with the second excitation light beam 13, the second Raman scattered light 33 is emitted from the sample 25. The second Raman scattered light 33 has a wavelength longer than that of the second excitation light beam 13. The second Raman scattered light 33 has a wavelength shorter than that of the first Raman scattered light 31. That is, the first Raman scattered light 31 is long-wavelength Raman scattered light, and the second Raman scattered light 33 is short-wavelength Raman scattered light. The second Raman scattered light 33 is reflected by the mirrors 21 and 22 through the objective lens 24 and the half mirror 23. The second Raman scattered light 33 is reflected by the dichroic mirror 20 and the mirror 19. The second Raman scattered light 33 passes through the low-pass filter 18 and is reflected by the mirror 26. The second Raman scattered light 33 is condensed by the condenser lens 28, passes through the slit 30, and enters the spectroscopic optical system 40. The position of the opening of the slit 30 is different from the position of the opening of the slit 29.

[0016] The spectroscopic optical system 40 includes collimator lenses 42 and 43, a first spectroscope 44, a second spectroscope 46, and a condenser optical element 49. The spectroscopic optical system 40 may further include a mirror 41.

[0017] The first Raman scattered light 31 is reflected by the mirror 41 and enters the collimator lens 42. The collimator lens 42 collimates the first Raman scattered light 31. The first Raman scattered light 31 passes through the collimator lens 42 and enters the first spectroscope 44. The first spectroscope 44 disperses the first Raman scattered light 31. The first Raman scattered light 31 dispersed by the first spectroscope 44 passes through the condensing optical element 49 and enters the photodetector 50. The condensing optical element 49 is, for example, a condensing lens. The condensing optical element 49 condenses the first Raman scattered light 31 dispersed by the first spectroscope 44 onto the light receiving surface 51 of the photodetector 50 as a plurality of first beam spots 32 (see FIG. 2).

[0018] The second Raman scattered light 33 is reflected by the mirror 41 and enters the collimator lens 43. The collimator lens 43 collimates the second Raman scattered light 33. The second Raman scattered light 33 passes through the collimator lens 43 and enters the second spectroscope 46. The second incident optical path 33i of the second Raman scattered light 33 to the second spectroscope 46 in the spectroscopic optical system 40 is different from the first incident optical path 31i of the first Raman scattered light 31 to the first spectroscope 44 in the spectroscopic optical system 40. The second spectroscope 46 disperses the second Raman scattered light 33. The second Raman scattered light 33 dispersed by the second spectroscope 46 passes through the condensing optical element 49 and enters the photodetector 50. The condensing optical element 49 condenses the second Raman scattered light 33 dispersed by the second spectroscope 46 onto the light receiving surface 51 of the photodetector 50 as a plurality of second beam spots 34 (see FIG. 2).

[0019] The second spectroscope 46 is composed of a larger number of spectroscopic optical elements than the first spectroscope 44. The spectroscopic optical element is, for example, a grating or a prism. The first spectroscope 44 is composed of one first spectroscopic optical element 45. The second spectroscope 46 is composed of two second spectroscopic optical elements 47, 48.

[0020] The photodetector 50 receives the first Raman scattered light 31 and the second Raman scattered light 33 output from the spectroscopic optical system 40. The photodetector 50 is, for example, a CCD detector. As shown in FIG. 2, the photodetector 50 has a light receiving surface 51 extending in a first direction (x direction) and a second direction (y direction) intersecting the first direction. The photodetector 50 includes a plurality of photodetection elements 52. The plurality of photodetection elements 52 are, for example, a plurality of CCD chips. The plurality of photodetection elements 52 are two-dimensionally arranged. Specifically, the plurality of photodetection elements 52 are arranged along the first direction (x direction) and the second direction (y direction) on the light receiving surface 51. The second direction is the wave number decomposition direction of the first Raman scattered light 31 by the first spectroscope 44 on the light receiving surface 51, and is also the wave number decomposition direction of the second Raman scattered light 33 by the second spectroscope 46 on the light receiving surface 51. The plurality of first beam spots 32 are separated from each other in the first direction (x direction). The plurality of second beam spots 34 are separated from each other in the first direction (x direction).

[0021] When the optical path of the second Raman scattered light 33 is displaced, the positions of the plurality of second beam spots 34 on the light receiving surface 51 of the photodetector 50 may be displaced from the positions of the plurality of first beam spots 32 (see, for example, the plurality of second beam spots 34b, 34c in FIG. 2). However, since the plurality of photodetection elements 52 are two-dimensionally arranged, even if the optical path of the second Raman scattered light 33 is displaced and the positions of the plurality of second beam spots 34 are displaced, the photodetector 50 can more reliably receive the second Raman scattered light 33 (the plurality of second beam spots 34). Similarly, even if the optical path of the first Raman scattered light 31 is displaced and the positions of the plurality of first beam spots 32 on the light receiving surface 51 of the photodetector 50 are displaced, the photodetector 50 can more reliably receive the first Raman scattered light 31 (the plurality of first beam spots 32).

[0022] Referring to FIG. 1, the signal processor 55 is connected to the photodetector 50. It processes a plurality of electrical signals output from the plurality of photodetection elements 52. The signal processor 55 is, for example, a microcomputer including a processor, a storage device such as a RAM (Random Access Memory), and a ROM (Read Only Memory). As the processor, for example, a CPU (Central Processing Unit) can be adopted. The RAM functions as a working memory that temporarily stores data processed by the processor. The storage device stores, for example, programs executed by the processor. By the processor executing the programs stored in the storage device, the signal processor 55 processes a plurality of electrical signals output from the plurality of photodetection elements 52. Various processes in the signal processor 55 are not limited to being executed by software and may be executed by dedicated hardware (electronic circuits).

[0023] The signal processor 55, for example, performs binning processing on a plurality of electrical signals output from the plurality of photodetection elements 52. Binning processing means collectively processing the electrical signals output from the photodetection elements 52 for each of a plurality of photodetection element groups 53a - 53k (see FIG. 2) among the plurality of photodetection elements 52. For example, each of the plurality of photodetection element groups 53a - 53k includes the photodetection elements 52 for two rows among the plurality of photodetection elements 52. The signal processor 55 may, for example, calculate the sum of the electrical signals output from the photodetection elements 52 for each of the plurality of photodetection element groups 53a - 53k, or may calculate the average of the electrical signals output from the photodetection elements 52 for each of the plurality of photodetection element groups 53a - 53k.

[0024] Even if the first Raman scattered light 31 and the second Raman scattered light 33 are weak, the binning process can surely obtain electrical signals for the first Raman scattered light 31 and the second Raman scattered light 33. Also, even if the optical path of the second Raman scattered light 33 is displaced and the positions of the plurality of second beam spots 34 on the light receiving surface 51 of the photodetector 50 are displaced (for example, refer to the plurality of second beam spots 34b, 34c in FIG. 2), the binning process enables obtaining the exact light intensity of each of the plurality of second beam spots 34. The binning process can obtain a more accurate Raman spectrum of the second Raman scattered light 33. Similarly, even if the optical path of the first Raman scattered light 31 is displaced and the positions of the plurality of first beam spots 32 on the light receiving surface 51 of the photodetector 50 are displaced, the binning process can obtain a more accurate Raman spectrum of the first Raman scattered light 31.

[0025] The Raman spectroscopic apparatus 1 may further include an illumination light source 60, an objective lens 24, a camera 63, and an imaging lens 62, and may be a Raman spectroscopic microscope.

[0026] The illumination light source 60 emits illumination light 61 that illuminates the sample 25. The illumination light source 60 is, for example, a light emitting diode (LED). The illumination light 61 is, for example, visible light. The illumination light 61 irradiated on the sample 25 is reflected by the half mirror 23 through the objective lens 24. The illumination light 61 enters the camera 63 through the imaging lens 62. The imaging lens 62 forms an image of the sample 25 on the light receiving surface 64 of the camera 63. The camera 63 includes, for example, a CMOS sensor.

[0027] The operation of the Raman spectroscopic apparatus 1 of the present embodiment will be described while comparing it with the Raman spectroscopic apparatuses of the first to third comparative examples.

[0028] The Raman spectroscopic apparatus of the first comparative example includes a first condensing optical element and a first photodetector for the first Raman scattered light 31, and a second condensing optical element and a second photodetector for the second Raman scattered light 33. In contrast, in the Raman spectroscopic apparatus 1 of the present embodiment, the condensing optical element 49 and the photodetector 50 are used for both the first Raman scattered light 31 and the second Raman scattered light 33. The Raman spectroscopic apparatus 1 of the present embodiment includes a smaller number of condensing optical elements and a smaller number of photodetectors than the Raman spectroscopic apparatus of the first comparative example. Therefore, the cost of the Raman spectroscopic apparatus 1 of the present embodiment is reduced compared to the Raman spectroscopic apparatus of the first comparative example.

[0029] Since the second wavelength of the second excitation light beam 13 is shorter than the first wavelength of the first excitation light beam 11, the wavelength range of the second Raman scattered light 33 corresponding to a certain measurement frequency range is narrower than the wavelength range of the first Raman scattered light 31 corresponding to the same measurement frequency range. In order to expand the measurement frequency range of the Raman spectrum for the second Raman scattered light 33, for example, to be about the same as the measurement frequency range of the Raman spectrum for the first Raman scattered light 31, it is necessary to make the angular dispersion of the second spectroscope 46 larger than the angular dispersion of the first spectroscope 44.

[0030] In the Raman spectroscopic apparatus of the second comparative example, the first spectroscope 44 and the second spectroscope 46 are composed of the same number of spectroscopic optical elements, and the spectroscopic optical elements constituting the second spectroscope 46 have a larger angular dispersion than the spectroscopic optical elements constituting the first spectroscope 44. However, as the wavelength resolution of the spectroscopic optical element increases, the cost of the spectroscopic optical element increases rapidly. Therefore, in the Raman spectroscopic apparatus of the second comparative example, when trying to expand the measurement frequency range of the Raman spectrum for the second Raman scattered light 33, for example, to be about the same as the measurement frequency range of the Raman spectrum for the first Raman scattered light 31, the cost of the Raman spectroscopic apparatus of the second comparative example increases.

[0031] On the other hand, in the Raman spectroscopic apparatus 1 of the present embodiment, the second spectroscope 46 is composed of a larger number of spectroscopic optical elements than the first spectroscope 44. Therefore, while using inexpensive spectroscopic optical elements for each of the plurality of spectroscopic optical elements constituting the second spectroscope 46, the angular dispersion of the second spectroscope 46 can be made larger than the angular dispersion of the first spectroscope 44. Therefore, even if the measurement frequency range of the Raman spectrum for the second Raman scattered light 33 is expanded to, for example, the same level as the measurement frequency range of the Raman spectrum for the first Raman scattered light 31, the cost of the Raman spectroscopic apparatus 1 of the present embodiment is reduced compared to the cost of the Raman spectroscopic apparatus of the second comparative example.

[0032] In the Raman spectroscopic apparatus of the third comparative example, the second incident optical path 33i of the second Raman scattered light 33 to the second spectroscope 46 in the spectroscopic optical system 40 is the same as the first incident optical path 31i of the first Raman scattered light 31 to the first spectroscope 44 in the spectroscopic optical system 40. Therefore, the Raman spectroscopic apparatus of the third comparative example requires a moving mechanism for switching between the first spectroscope 44 and the second spectroscope 46.

[0033] On the other hand, in the Raman spectroscopic apparatus 1 of the present embodiment, the second incident optical path 33i of the second Raman scattered light 33 to the second spectroscope 46 in the spectroscopic optical system 40 is different from the first incident optical path 31i of the first Raman scattered light 31 to the first spectroscope 44 in the spectroscopic optical system 40. Therefore, the Raman spectroscopic apparatus 1 can omit the moving mechanism for moving the first spectroscope 44 and the second spectroscope 46. The cost of the Raman spectroscopic apparatus 1 of the present embodiment is reduced compared to the cost of the Raman spectroscopic apparatus of the third comparative example. The Raman spectroscopic apparatus 1 of the present embodiment can accurately and stably obtain the Raman spectrum of the first Raman scattered light 31 and the Raman spectrum of the second Raman scattered light 33 compared to the Raman spectroscopic apparatus of the third comparative example.

[0034] In the Raman spectroscopic apparatus 1 according to a modification of the present embodiment, the number of excitation light sources may be three or more.

[0035] [Aspect] Those skilled in the art will understand that the above-described exemplary embodiments are specific examples of the following aspects.

[0036] (Item 1) A Raman spectroscopic apparatus according to one aspect includes a spectroscopic optical system and a photodetector. The spectroscopic optical system includes a first spectroscope and a second spectroscope. The first spectroscope spectroscopically analyzes first Raman scattered light emitted from a sample when the sample is irradiated with a first excitation light beam. The second spectroscope spectroscopically analyzes second Raman scattered light emitted from the sample when the sample is irradiated with a second excitation light beam having a wavelength shorter than that of the first excitation light beam and having a wavelength shorter than that of the first Raman scattered light. The photodetector receives the first Raman scattered light and the second Raman scattered light output from the spectroscopic optical system. A second incident optical path of the second Raman scattered light to the second spectroscope in the spectroscopic optical system is different from a first incident optical path of the first Raman scattered light to the first spectroscope in the spectroscopic optical system. The second spectroscope is composed of a larger number of spectroscopic optical elements than the first spectroscope.

[0037] The photodetector is used for both the first Raman scattered light and the second Raman scattered light. Therefore, the cost of the Raman spectroscopic apparatus is reduced. Further, since the second spectroscope is composed of a larger number of spectroscopic optical elements than the first spectroscope, while using low-cost spectroscopic optical elements as the spectroscopic optical elements constituting the second spectroscope, the angular dispersion of the second spectroscope can be increased. Therefore, the measurement frequency range of the Raman spectrum for the second Raman scattered light can be expanded and the cost of the Raman spectroscopic apparatus is reduced. Furthermore, the second incident optical path of the second Raman scattered light to the second spectroscope in the spectroscopic optical system is different from the first incident optical path of the first Raman scattered light to the first spectroscope in the spectroscopic optical system. Therefore, the Raman spectroscopic apparatus can omit a moving mechanism for moving the first spectroscope and the second spectroscope. The cost of the Raman spectroscopic apparatus is reduced.

[0038] (Item 2) In the Raman spectroscopic apparatus according to Item 1, the first spectroscope is composed of one spectroscopic optical element. The second spectroscope is composed of two spectroscopic optical elements.

[0039] Therefore, the number of spectroscopic optical elements that make up the first spectroscope and the second spectroscope can be minimized. The cost of the Raman spectroscopic apparatus is reduced.

[0040] (Item 3) In the Raman spectroscopic apparatus according to Item 1 or Item 2, the spectroscopic optical system includes a condensing optical element. The condensing optical element condenses the first Raman scattered light output from the first spectroscope and the second Raman scattered light output from the second spectroscope onto a photodetector.

[0041] The condensing optical element is used for both the first Raman scattered light and the second Raman scattered light. Therefore, the cost of the Raman spectroscopic apparatus is reduced.

[0042] (Item 4) In the Raman spectroscopic apparatus according to any one of Items 1 to 3, the photodetector includes a plurality of photodetection elements arranged two-dimensionally.

[0043] Therefore, even if the optical path of the first Raman scattered light or the optical path of the second Raman scattered light is displaced, the photodetector can more reliably receive the first Raman scattered light and the second Raman scattered light. The Raman spectroscopic apparatus can more reliably obtain a Raman spectrum. The degree of freedom in the design of the optical system of the Raman spectroscopic apparatus is improved.

[0044] (Item 5) The Raman spectroscopic apparatus according to Item 4 further includes a signal processor connected to the photodetector. The signal processor performs binning processing on a plurality of electrical signals output from the plurality of photodetection elements.

[0045] Therefore, even if the first Raman scattered light and the second Raman scattered light are weak, electrical signals regarding the first Raman scattered light and the second Raman scattered light can be reliably obtained. Even if the optical path of the first Raman scattered light or the optical path of the second Raman scattered light is displaced, the Raman spectrum of the first Raman scattered light and the Raman spectrum of the second Raman scattered light can be obtained more accurately.

[0046] The embodiments and their modifications disclosed this time should be considered to be illustrative in all respects and not restrictive. The scope of the present disclosure is indicated by the claims rather than the above description, and is intended to include all modifications within the meaning and scope equivalent to the claims.

Explanation of Reference Numerals

[0047] 1 Raman spectrometer, 10 first excitation light source, 11 first excitation light beam, 12 second excitation light source, 13 second excitation light beam, 15, 16, 19, 21, 22, 26, 41 mirrors, 17, 18 low-pass filters, 20 dichroic mirror, 23 half mirror, 24 objective lens, 25 sample, 25a sample support, 27, 28 condenser lenses, 29, 30 slits, 31 first Raman scattered light, 31i first incident optical path, 32 first beam spot, 33 second Raman scattered light, 33i second incident optical path, 34, 34b, 34c second beam spots, 40 spectroscopic optical system, 42, 43 collimator lenses, 44 first spectroscope, 45 first spectroscopic optical element, 46 second spectroscope, 47, 48 second spectroscopic optical elements, 49 condensing optical element, 50 photodetector, 51 light receiving surface, 52 photodetection element, 53a - 53k photodetection element group, 55 signal processor, 60 illumination light source, 61 illumination light, 62 imaging lens, 63 camera, 64 light receiving surface.

Claims

1. A spectroscopic optical system and, a photodetector, and the spectroscopic optical system includes a first spectrometer that spectrally analyzes first Raman scattered light radiated from the sample when the sample is irradiated with a first excitation light beam, and a second spectrometer that spectrally analyzes second Raman scattered light radiated from the sample when the sample is irradiated with a second excitation light beam having a wavelength shorter than that of the first excitation light beam and having a wavelength shorter than that of the first Raman scattered light, the photodetector receives the first Raman scattered light and the second Raman scattered light output from the spectroscopic optical system, and the second spectrometer is composed of a larger number of spectroscopic optical elements than the first spectrometer, a Raman spectroscopic apparatus.

2. the first spectrometer is composed of one spectroscopic optical element, and the second spectrometer is composed of two spectroscopic optical elements, the Raman spectroscopic apparatus according to claim 1.

3. the spectroscopic optical system includes a condensing optical element, and the condensing optical element condenses the first Raman scattered light output from the first spectrometer and the second Raman scattered light output from the second spectrometer onto the photodetector, the Raman spectroscopic apparatus according to claim 1.

4. the photodetector includes a plurality of photodetection elements arranged two-dimensionally, the Raman spectroscopic apparatus according to claim 1.

5. further includes a signal processor connected to the photodetector, and the signal processor performs binning processing on a plurality of electrical signals output from the plurality of photodetection elements, the Raman spectroscopic apparatus according to claim 4.

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