JP2015094728A - Spectrometer and confocal scanning type microscope including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology that enables light of a desired wavelength to be detected with high detection efficiency.SOLUTION: A spectrometer 10 comprises: a reflection type VPH diffraction grating 20 that spectrally separates light IL for each wavelength; a converging optical system 50 that allows primary-order diffraction light generated due to diffraction by the reflection type VPH diffraction grating 20 to be converged; an optical detector 60 that is disposed at a position where the primary-order diffraction light is converged by the converging optical system 50; and a mirror 30 that allows 0-order diffraction light generated by the reflection type VPH diffraction grating 20 to be incident upon the reflection type VPH diffraction grating 20 by reflecting the 0-order diffraction light. The mirror 30 has a reflection surface 31 parallel to a grating surface of the reflection type VPH diffraction grating 20, and the mirror is disposed so that the reflection surface 31 is located at a position upon which the 0-order diffraction light is incident and the primary-order diffraction light is not incident.

Description

  The present invention relates to a spectroscopic device and a confocal scanning microscope including the spectroscopic device.

  At present, in the field of fluorescence microscopes, a microscope equipped with a spectroscopic device that acquires wavelength information of light by spectroscopically detecting light from a specimen has become mainstream. And since the fluorescence detected by fluorescence observation is very weak, high detection efficiency is calculated | required by the spectroscopic apparatus contained in a fluorescence microscope.

  In a spectroscopic device, in general, light is split by a diffraction grating designed so that the diffraction efficiency of first-order diffracted light (hereinafter referred to as first-order diffraction efficiency) is high. In recent years, a spectroscopic device has been developed that achieves a detection efficiency as high as about 80 percent by employing a diffraction grating having a high first-order diffraction efficiency.

  In addition, a technique for realizing a spectroscopic device with high detection efficiency has been studied from a viewpoint different from the improvement of the single unit performance of the diffraction grating. For example, Patent Document 1 discloses a technique for reusing zero-order diffracted light generated in a diffraction grating. The spectrum analysis unit disclosed in Patent Document 1 has a configuration in which the 0th-order diffracted light beam is circulated by causing the 0th-order diffracted light beam generated by the diffraction grating to enter the diffraction grating again with a mirror.

JP 2007-286043 A

  Incidentally, the diffraction grating has a characteristic that the peak wavelength of the diffraction efficiency changes depending on the incident angle. Therefore, in order to detect fluorescence with a desired wavelength corresponding to a fluorescent substance with high efficiency, it is desirable that the spectroscopic device has a configuration that can change the incident angle by rotating the diffraction grating.

  However, since the spectrum analysis unit disclosed in Patent Document 1 is not configured to change the incident angle by rotating the diffraction grating, it is difficult to detect light with a desired wavelength with high efficiency.

  In view of the above circumstances, it is an object of the present invention to provide a spectroscopic device that can detect light of a desired wavelength with high detection efficiency and a confocal scanning microscope including the spectroscopic device.

  According to a first aspect of the present invention, there is provided a reflective diffractive element that separates light for each wavelength, a condensing optical system that condenses diffracted light of a specific order generated by diffraction at the diffractive element, and the specific order of A photodetector arranged at a position where diffracted light is collected by the condensing optical system, and a zero-order diffracted light generated by the diffractive element having a reflecting surface and incident from a predetermined direction, and the specific A reflecting member that is arranged so that the reflecting surface is positioned parallel to the grating surface of the diffractive element at a position where the diffracted light of the order is not incident, and that reflects the zero-order diffracted light and enters the diffractive element. Providing the device.

  According to a second aspect of the present invention, there is provided the spectroscopic device according to the first aspect, wherein the diffractive element is rotatably arranged so that an incident angle of light incident on the diffractive element changes. provide.

  According to a third aspect of the present invention, in the spectroscopic device according to the second aspect, the reflection member is rotatable so as to rotate by the same angle in the same direction as the diffraction element as the diffraction element rotates. A spectroscopic device is provided.

  According to a fourth aspect of the present invention, in the spectroscopic device according to the third aspect, the diffraction element has a periodic structure in a first direction parallel to the grating surface, and is parallel to the grating surface. A spectroscopic device having a rotation axis in a direction perpendicular to the first direction is provided.

  According to a fifth aspect of the present invention, in the spectroscopic device according to the fourth aspect, the diffractive element is arranged such that light incident on the diffractive element has a velocity component parallel to the rotation axis. I will provide a.

  According to a sixth aspect of the present invention, in the spectroscopic device according to any one of the first to fifth aspects, the light exits from the diffraction element between the diffraction element and the reflecting member. There is provided a spectroscopic device comprising a λ / 4 plate disposed at a position where the zeroth-order diffracted light is incident and the zeroth-order diffracted light reflected by the reflecting member is incident.

  A seventh aspect of the present invention is the spectroscopic device according to any one of the first to sixth aspects, wherein the diffraction element is periodically refracted in a first direction parallel to the grating plane. A volume hologram layer that diffracts incident light, a second reflecting member disposed on one surface of the volume hologram layer, a parallel plate that transmits light disposed on the other surface of the volume hologram layer, and A spectroscopic device that is a reflective volume hologram diffraction grating is provided.

  According to an eighth aspect of the present invention, in the spectroscopic device according to any one of the first to seventh aspects, the photodetector detects the diffracted light of the specific order in a different wavelength band. A spectroscopic device including a plurality of light detection elements is provided.

  According to a ninth aspect of the present invention, there is provided a confocal scanning microscope comprising the spectroscopic device according to any one of the first to eighth aspects.

  ADVANTAGE OF THE INVENTION According to this invention, the spectroscopic device which can detect the light of a desired wavelength with high detection efficiency, and a confocal scanning microscope provided with the same can be provided.

1 is a diagram illustrating a configuration of a confocal scanning microscope according to Example 1. FIG. 1 is a diagram illustrating a configuration of a spectroscopic device according to Example 1. FIG. 3 is a plan view of a diffraction unit according to Embodiment 1. FIG. 6 is a diagram for explaining the operation of the diffraction element according to Embodiment 1. FIG. It is a figure for demonstrating the relationship between an incident angle and a diffraction angle. 6 is a diagram illustrating a configuration of a diffraction unit according to Example 2. FIG. 6 is a plan view of a diffraction unit according to Embodiment 2. FIG. 6 is a diagram illustrating a configuration of a diffraction unit according to Example 3. FIG.

  FIG. 1 is a diagram illustrating the configuration of a confocal scanning microscope 1 according to the present embodiment. A confocal scanning microscope 1 illustrated in FIG. 1 is a fluorescence microscope provided with a spectroscopic device 10 that spectrally detects fluorescence from a specimen S.

  The confocal scanning microscope 1 includes a laser 2 that emits laser light that is excitation light on an illumination optical path, a dichroic mirror 3 that reflects the laser light emitted from the laser 2 and transmits fluorescence from the specimen S, and A galvanometer mirror 4 that is a scanning unit for scanning the sample S with laser light, and a scanning optical system 5 that irradiates the sample S with laser light are provided.

  The confocal scanning microscope 1 includes a confocal lens 6 that condenses the fluorescence transmitted through the dichroic mirror 3 in addition to the scanning optical system 5, the galvanometer mirror 4, and the dichroic mirror 3 on the detection optical path. A confocal stop 7 in which a focal pinhole 8 is formed; a collimating lens 9 for collimating the fluorescence that has passed through the confocal pinhole 8; and a spectroscopic device 10 on which the fluorescence from the collimating lens 9 enters as a parallel light beam. ing. The dichroic mirror 3, the galvanometer mirror 4, and the scanning optical system 5 are provided on a common optical path that is an illumination optical path and a detection optical path.

  In the confocal scanning microscope 1, the laser light emitted from the laser 2 is irradiated onto the sample S by the scanning optical system 5 via the dichroic mirror 3 and the galvanometer mirror 4. Here, since the galvanometer mirror 4 is disposed at the pupil position (or pupil conjugate position) of the scanning optical system 5, the laser beam is positioned on the sample S in accordance with the direction in which the galvanometer mirror 4 deflects the laser beam. Is irradiated. Therefore, by controlling the operation of the galvanometer mirror 4, the specimen S can be scanned with the laser light.

  In the sample S irradiated with the laser light, fluorescence is generated. The fluorescence generated from the specimen S is transmitted through the dichroic mirror 3 incident through the scanning optical system 5 and the galvanometer mirror 4, and is condensed on the confocal stop 7 by the confocal lens 6. Since the confocal pinhole 8 is formed in the confocal stop 7 at a position optically conjugate with the front focal position of the scanning optical system 5, the front side of the scanning optical system 5 on or in the specimen S is formed. Only the fluorescence generated from the focal position passes through the confocal pinhole 8 and the confocal stop 7. The fluorescence that has passed through the confocal stop 7 is then converted into a parallel light beam by the collimator lens 9 and enters the spectroscopic device 10.

FIG. 2 is a diagram illustrating the configuration of the spectroscopic device 10 according to the present embodiment. FIG. 3 is a plan view of the diffraction unit 40 included in the spectroscopic device 10 according to the present embodiment. The XYZ coordinate system shown in FIGS. 2 and 3 is an orthogonal coordinate system provided for convenience of direction reference.
First, the configuration and operation of the spectroscopic device 10 will be outlined with reference to FIG.

  The spectroscopic device 10 is a device that spectrally detects and detects light IL (fluorescence) converted into a parallel light beam by the collimating lens 9. As illustrated in FIG. 2, the spectroscopic device 10 includes a reflective volume hologram (volume phase holographic, hereinafter referred to as VPH) diffraction grating 20 and a reflective member, which are reflective diffractive elements that split incident light for each wavelength. The diffraction unit 40 including the mirror 30, the condensing optical system 50 that condenses the first-order diffracted light generated by the diffraction at the reflective VPH diffraction grating 20, and the first-order diffracted light is condensed by the condensing optical system 50. And a light detector 60 including a plurality of light detecting elements 61 that detect the first-order diffracted light in different wavelength bands, each disposed at a position.

  In the spectroscopic device 10 configured as described above, the light IL incident on the spectroscopic device 10 as a parallel light beam first enters the diffraction unit 40. The light IL incident on the diffraction unit 40 is diffracted by the diffraction unit 40, separated into 0th-order diffracted light L0 and diffracted light of each order, and is emitted from the diffraction unit 40. At this time, the diffracted light of each order is emitted from the reflective VPH diffraction grating 20 at a different angle for each wavelength. In FIG. 2, only the 0th-order diffracted light L0, the red first-order diffracted light L1r, and the blue first-order diffracted light L1b are shown. The first-order diffracted light (first-order diffracted light L1r, first-order diffracted light L1b) emitted from the diffraction unit 40 is incident on the condensing optical system 50 disposed on the optical path at different angles for each wavelength. The light is condensed for each wavelength on the photodetector 60 arranged on the focal plane. As a result, the first-order diffracted light is detected by the light detecting element 61 that is different for each wavelength band, and the wavelength information of the light IL is obtained.

Next, the configuration and operation of the diffraction unit 40 included in the spectroscopic device 10 will be described in more detail with reference to FIGS. 2 and 3.
The diffraction unit 40 includes a reflective VPH diffraction grating 20 and a mirror 30.

  The reflection type VPH diffraction grating 20 has a three-layer structure, and a transmission type VPH layer 21 that diffracts light IL incident on the reflection type VPH diffraction grating 20 as a parallel light beam from a predetermined direction; The mirror 22 which is a reflecting member which contacts and is arrange | positioned on one surface of the VPH layer 21 and the protective glass 23 which contacts the VPH layer 21 and is arrange | positioned on the other surface of the VPH layer 21 are included. The reflective VPH diffraction grating 20 is configured to sandwich the VPH layer 21 between the mirror 22 and the protective glass 23, and the protective glass 23, the VPH layer 21, and the mirror 22 are arranged in this order from the light IL incident side. Yes.

  The VPH layer 21 has a constant thickness in the Y direction and has a refractive index that periodically differs in the X direction. With this structure, the VPH layer 21 has specific wavelength dispersion characteristics in the X direction, and can split the incident light IL in the X direction and emit it in different directions for each wavelength. More specifically, the VPH layer 21 diffracts the light IL and emits diffracted light at different angles for each wavelength with respect to a plane whose normal is the X direction. Hereinafter, the X direction is referred to as the lattice direction as necessary, and the plane of the VPH layer 21 that is parallel to the lattice direction (XZ plane in this embodiment) is referred to as the lattice plane.

  The VPH layer 21 is basically the same as the VPH layer of the conventional transmission type VPH diffraction grating. However, the thickness of the VPH layer 21 (that is, the width in the Y direction) may be about half of the thickness of the VPH layer of the conventional transmission type VPH diffraction grating. This is because light incident on the VPH layer 21 is reflected by the mirror 22 and reciprocates through the VPH layer 21 as will be described later.

  The mirror 22 is a reflecting member whose reflecting surface is a plane in contact with the VPH layer 21. Hereinafter, in order to distinguish from the mirror 30 which is also a reflecting member, the mirror 22 is also referred to as a second reflecting member as necessary.

  The protective glass 23 is a protective member that protects the VPH layer 21 and is a parallel plate that transmits light (at least light having a wavelength to be detected). An antireflection film may be formed on the surface of the protective glass 23.

  The mirror 30 is a reflecting member for reflecting the 0th-order diffracted light L0 emitted from the reflection type VPH diffraction grating 20 generated by the reflection type VPH diffraction grating 20 and making it enter the reflection type VPH diffraction grating 20 again. The mirror 30 is disposed such that the reflection surface 31 is in contact with the surface of the protective glass 23, and is fixed to the protective glass 23. For this reason, the reflecting surface 31 is parallel to the grating surface of the reflective VPH diffraction grating 20.

  As shown in FIG. 3, the reflective VPH diffraction grating 20 has a reflective surface 31 at a position where the 0th-order diffracted light L0 generated by the reflective VPH diffraction grating 20 (VPH layer 21) is incident and the first-order diffracted light is not incident. The mirror 30 is disposed on a part of the surface of the protective glass 23 so as to be parallel to the lattice plane (XZ plane) of the (VPH layer 21).

  Further, the reflection type VPH diffraction grating 20 is rotatably arranged so that the incident angle of the light IL incident on the reflection type VPH diffraction grating 20 from a predetermined direction changes. More specifically, the reflective VPH diffraction grating 20 has a rotation axis AR in the Z direction that is parallel to the grating surface (XZ plane) and perpendicular to the grating direction (X direction), and is parallel to the Z direction. It is arranged so as to be rotatable with respect to the rotation axis AR.

  Further, since the mirror 30 is fixed to the reflection type VPH diffraction grating 20 (protective glass 23), the same direction as the reflection type VPH diffraction grating 20 in the spectroscopic device 10 as the reflection type VPH diffraction grating 20 rotates. Are rotatably arranged so as to rotate by the same angle. That is, in the diffraction unit 40, the parallel positional relationship between the reflection surface 31 and the grating surface is maintained regardless of the rotation (direction) of the reflection type VPH diffraction grating 20. Further, the reflection type VPH diffraction grating 20 is arranged in the spectroscopic device 10 so that the light IL incident on the reflection type VPH diffraction grating 20 has a velocity component (Z direction component) parallel to the rotation axis AR. That is, the light IL is arranged so as not to be parallel to a plane having the rotation axis AR as a normal line.

  In the diffraction unit 40 configured as described above, the light IL incident on the diffraction unit 40 as a parallel light beam is incident on the protective glass 23 and is diffracted by the VPH layer 21 incident through the protective glass 23.

  The first-order diffracted light diffracted by the VPH layer 21 passes through the VPH layer 21 and is emitted toward the mirror 22, but immediately is regularly reflected by the mirror 22. For this reason, as shown in FIG. 4, the first-order diffracted light (first-order diffracted light L1r, first-order diffracted light L1b) obtained by the reflection type VPH diffraction grating 20 is defined as the emission direction determined by the wavelength dispersion characteristics of the VPH layer 21. It proceeds in a direction symmetric with respect to the 22 reflecting surfaces. Thereafter, the first-order diffracted light reflected by the mirror 22 passes through the VPH layer 21 and the protective glass 23 and is emitted toward the condensing optical system 50 at different angles for each wavelength.

  The light that has not been diffracted by the VPH layer 21, that is, the 0th-order diffracted light L 0 generated by the diffraction by the VPH layer 21 travels straight through the VPH layer 21. Thereafter, the light is regularly reflected by the reflecting surface of the mirror 22 and the reflecting surface of the mirror 30, and enters the VPH layer 21 again. At this time, since the grating surface, the reflecting surface of the mirror 22, and the reflecting surface 31 of the mirror 30 are parallel, the 0th-order diffracted light L0 that reenters the VPH layer 21 enters the VPH layer 21 at the same angle as the light IL. For this reason, the first-order diffracted light generated by the re-incident zero-order diffracted light L0 being diffracted by the VPH layer 21 is the same angle for each wavelength as the first-order diffracted light generated by the light IL being diffracted by the VPH layer 21. The light is emitted from the diffraction unit 40 toward the condensing optical system 50. The 0th-order diffracted light L0 that has not been diffracted by re-incidence is regularly reflected by the reflecting surface of the mirror 22 and is emitted from the diffraction unit 40 in a direction deviating from the condensing optical system 50.

  Therefore, in the spectroscopic device 10 and the confocal scanning microscope 1 according to the present embodiment, the first-order diffracted light generated when the light IL is diffracted by the VPH layer 21 and the re-entered zero-order diffracted light L0 are diffracted by the VPH layer 21. The first-order diffracted light generated by this is condensed on the same light detecting element 61 for each wavelength by the condensing optical system 50 and detected. For this reason, according to the spectroscopic device 10 and the confocal scanning microscope 1, the diffraction unit 40 can guide the first-order diffracted light to the condensing optical system 50 with an efficiency equal to or higher than the diffraction efficiency of the VPH layer 21. Folding light can be detected with high detection efficiency.

  In addition, since the protective glass 23 is provided on the reflective VPH diffraction grating 20, regular reflection may occur at the interface between the protective glass 23 and the VPH layer 21. However, the reflected light regularly reflected at this interface is reflected by the reflecting surface 31 of the mirror 30 and is incident on the VPH layer 21 in the same manner as the 0th-order diffracted light L0. For this reason, a part of the reflected light regularly reflected at the interface can be detected as the first-order diffracted light. This contributes to improvement in the detection efficiency of the first-order diffracted light.

As shown in FIG. 5, θ is an incident angle that is an angle formed by the normal NL of the lattice plane of the VPH layer 21 and the light IL, β is a diffraction angle of the first-order diffracted light L1, and λ is the first-order diffracted light. When the wavelength of L1 and N are the lattice constant of the VPH layer 21, the emission direction of the first-order diffracted light for each wavelength determined by the wavelength dispersion characteristic of the VPH layer 21 can be calculated by the equation (1). Further, the incident angle θ1 at which the efficiency of the first-order diffracted light with the wavelength λp is maximized can be calculated by the equation (2).
sin θ + sin β = Nλ (1)
sin θ1 = Nλp / 2 (2)

  The direction of the first-order diffracted light L1 emitted from the diffractive unit 40 is different from the emission direction of the first-order diffracted light L1 indicated by the diffraction angle β in FIG. Symmetric direction. Therefore, if the light IL is incident from the first region shown in FIG. 5, the first-order diffracted light L1 is emitted to the first region. In contrast, the 0th-order diffracted light L0 is emitted to the fourth region shown in FIG. Accordingly, in the spectroscopic device 10 and the confocal scanning microscope 1 according to the present embodiment, the first-order diffracted light L1 and the 0th-order diffracted light L0 are emitted in different directions, so that the 0th-order diffracted light L0 is not detected together with the first-order diffracted light L1. Can be easily realized.

  As shown in FIG. 3, the diffraction unit 40 is arranged so that the light IL has a velocity component parallel to the rotation axis AR. For this reason, according to the spectroscopic device 10 and the confocal scanning microscope 1 according to the present embodiment, the light IL and the first-order diffracted light can be separated in a direction parallel to the rotation axis AR. A configuration that does not act on the light IL can be easily realized.

  Furthermore, in the spectroscopic device 10 and the confocal scanning microscope 1 according to the present embodiment, the wavelength of the first-order diffracted light having the maximum diffraction efficiency can be adjusted by rotating the diffraction unit 40 with respect to the rotation axis AR. it can. In addition, since the parallel relationship between the reflecting surface 31 and the grating surface is always maintained, the 0th-order diffracted light L0 can be reincident on the VPH layer 21 at the same incident angle as that of the light IL regardless of the rotation (direction) of the diffraction unit 40. it can. Therefore, according to the spectroscopic device 10 and the confocal scanning microscope 1 according to the present embodiment, light having a desired wavelength can be detected with high detection efficiency.

  FIG. 6 is a diagram illustrating the configuration of the diffraction unit 80 according to the present embodiment. FIG. 7 is a plan view of the diffraction unit 80 according to the present embodiment. The XYZ coordinate system shown in FIGS. 6 and 7 is an orthogonal coordinate system provided for convenience of direction reference. The confocal scanning microscope and the spectroscopic device according to the present embodiment are the same as the confocal scanning microscope 1 and the spectroscopic device 10 according to the first embodiment, except that the diffraction unit 80 is included instead of the diffraction unit 40. is there.

  The configuration of the diffraction unit 80 according to the present embodiment is different from the configuration of the diffraction unit 40 according to the first embodiment in that a mirror 70 is provided instead of the mirror 30. Since other configurations are the same as those of the diffraction unit 40 according to the embodiment, the same components are denoted by the same reference numerals and description thereof is omitted.

  Similar to the mirror 30, the mirror 70 reflects the 0th-order diffracted light emitted from the reflective VPH diffraction grating 20 generated by the reflective VPH diffraction grating 20 and re-enters the reflective VPH diffraction grating 20. It is. Further, the mirror 70 is disposed such that the reflecting surface 31 is in contact with the surface of the protective glass 23 and is fixed to the protective glass 23, a point disposed on a part of the surface of the protective glass 23, and the reflecting surface 71. Is the same as the mirror 30 in that the 0th-order diffracted light generated by the VPH layer 21 is incident and the first-order diffracted light is not incident on the lattice plane (XZ plane) of the VPH layer 21. is there.

  6 and 7, the mirror 70 is configured such that the 0th-order diffracted light L0 generated in the VPH layer 21 is incident on the reflecting surface 71 of the mirror 70 a plurality of times (here, twice). The point is different from the mirror 30. More specifically, the mirror 70 has a side parallel to the light IL projected on the XZ plane so that the zero-order diffracted light L0 is incident on the mirror 70 a plurality of times and the first-order diffracted light is not blocked by the mirror 70. doing.

  According to the spectroscopic device and the confocal scanning microscope provided with the diffraction unit 80 configured as described above, the first time with higher detection efficiency than the spectroscopic device 10 and the confocal scanning microscope 1 according to the first embodiment. Folding light can be detected. Other effects are the same as those of the spectroscopic device 10 and the confocal scanning microscope 1 according to the first embodiment.

  FIG. 8 is a diagram illustrating the configuration of the diffraction unit 100 according to the present embodiment. The XYZ coordinate system shown in FIG. 8 is an orthogonal coordinate system provided for convenience of direction reference. The confocal scanning microscope and the spectroscopic device according to the present embodiment are the same as the confocal scanning microscope 1 and the spectroscopic device 10 according to the first embodiment, except that the diffraction unit 100 is included instead of the diffraction unit 40. is there.

  The configuration of the diffraction unit 100 according to the present embodiment is different from the configuration of the diffraction unit 40 according to the first embodiment in that a λ / 4 plate 90 is provided between the reflective VPH diffraction grating 20 and the mirror 30. Since other configurations are the same as those of the diffraction unit 40 according to the first embodiment, the same components are denoted by the same reference numerals, and description thereof is omitted.

  The λ / 4 plate 90 is the same as the mirror 30 in that the 0th-order diffracted light L0 generated by the reflective VPH diffraction grating 20 (VPH layer 21) is incident and the 1st-order diffracted light is not incident. is there. In FIG. 8, the mirror 30 and the reflection type VPH diffraction grating 20 are spaced apart from each other. However, the mirror 30 is provided with the reflection type VPH diffraction grating 20 so that the parallel relationship between the grating surface and the reflection surface 31 is maintained. Are configured to rotate in the same direction by the same rotation angle.

  By the way, the diffractive element generally has different diffraction efficiencies depending on the polarization direction, and has higher diffraction efficiency for S-polarized light than for P-polarized light. On the other hand, the fluorescence detected by the fluorescence microscope is randomly polarized light and includes light of various polarization directions. Considering these things, in the spectroscopic device according to the present embodiment in which the light IL that is fluorescent light is incident, the 0th-order diffracted light L0 emitted from the reflective VPH diffraction grating 20 without being diffracted by the VPH layer 21 is more P-polarized. It is thought that many are included.

  In the diffraction unit 100, the 0th-order diffracted light L0 generated by the VPH layer 21 is reflected by the reflecting surface 31 and enters the VPH layer 21 again, but passes through the λ / 4 plate 90 twice before entering the VPH layer 21 again. However, the phase changes by 180 degrees. For this reason, when entering the VPH layer 21 again, the 0th-order diffracted light L0 contains more S-polarized light. Therefore, the diffraction efficiency at the time of re-incidence is improved as compared with the diffraction efficiency at the time of first incidence.

  According to the spectroscopic device and the confocal scanning microscope according to the present embodiment including the diffraction unit 100 configured as described above, the diffraction efficiency at the time of re-incidence is improved. Therefore, the spectroscopic device 10 according to the first embodiment. The first-order diffracted light can be detected with higher detection efficiency than the confocal scanning microscope 1.

Moreover, according to the spectroscopic device and the confocal scanning microscope according to the present embodiment, the surface of the protective glass 23 and the reflecting surface 31 are separated from each other. For this reason, in addition to the reflected light that is regularly reflected at the interface between the protective glass 23 and the VPH layer 21, the reflected light that is regularly reflected by the surface of the protective glass 23 can also be incident on the mirror 30. Thereby, the specularly reflected light generated on both surfaces of the protective glass 23 can be incident on the VPH layer 21 and a part thereof can be detected as the first-order diffracted light. This point also contributes to higher detection efficiency than the spectroscopic device 10 and the confocal scanning microscope 1 according to the first embodiment.
Other effects are the same as those of the spectroscopic device 10 and the confocal scanning microscope 1 according to the first embodiment.

  The embodiments described above are specific examples for facilitating the understanding of the invention, and the present invention is not limited to these embodiments. The spectroscopic device and the confocal scanning microscope can be variously modified and changed without departing from the concept of the present invention defined by the claims.

  For example, the confocal scanning microscope is not limited to a fluorescent microscope whose observation target is a fluorescent specimen, and may be any microscope that acquires wavelength information. In addition, although the first-order diffracted light is exemplified as the diffracted light to be detected, other orders of diffracted light may be detected. Further, although the reflection type VPH diffraction grating 20 is exemplified as the diffraction element, the diffraction element may be a diffraction grating having a periodic structure in a grating direction parallel to the grating surface, for example, a blazed diffraction grating or a grating. It may be a type of diffraction grating. In particular, a reflection type diffraction grating is desirable. However, if this is a reflection type diffraction grating, specular reflection light generated before diffraction (for example, specular reflection light generated on both surfaces of the protective glass 23) is 0. This is because the light is emitted in the same direction as the next diffracted light. Since the specularly reflected light and the 0th-order diffracted light are emitted in the same direction, they can be reincident on the diffraction grating by a common reflecting member.

DESCRIPTION OF SYMBOLS 1 ... Confocal scanning microscope 2 ... Laser 3 ... Dichroic mirror 4 ... Galvano mirror 5 ... Scanning optical system 6 ... Confocal lens 7 ... Confocal stop 8 ...・ Confocal pinhole 9 ... collimating lens 10 ... spectroscopic device 20 ... reflection type VPH diffraction grating 21 ... VPH layers 22, 30, 70 ... mirror 23 ... protective glasses 31, 71・ ・ ・ Reflection surfaces 40, 80, 100 ・ ・ ・ Diffraction unit 50 ・ ・ ・ Condensing optical system 60 ・ ・ ・ Photo detector 61 ・ ・ ・ Photo detection element 90 ・ ・ ・ λ / 4 plate S ・ ・ ・ Sample IL: Light L0: 0th order diffracted light L1, L1b, L1r: 1st order diffracted light AR: Rotating axis

Claims (9)

A reflective diffractive element that splits light into wavelengths,
A condensing optical system that condenses diffracted light of a specific order generated by diffraction by the diffraction element;
A photodetector disposed at a position where the specific-order diffracted light is condensed by the condensing optical system;
The reflection surface is parallel to the grating surface of the diffractive element at a position where a 0th-order diffracted light generated by the diffractive element where light enters from a predetermined direction is incident and no diffracted light of the specific order is incident. A spectroscopic device comprising: a reflecting member that is disposed so as to reflect the 0th-order diffracted light and to enter the diffractive element. The spectroscopic device according to claim 1,
The spectroscopic device, wherein the diffraction element is rotatably arranged so that an incident angle of light incident on the diffraction element changes. The spectroscopic device according to claim 2,
The spectroscopic device, wherein the reflecting member is rotatably arranged so as to rotate by the same angle in the same direction as the diffraction element as the diffraction element rotates. The spectroscopic device according to claim 3.
The diffraction element is
Having a periodic structure in a first direction parallel to the lattice plane;
A spectroscopic device having a rotation axis in a direction parallel to the lattice plane and perpendicular to the first direction. The spectroscopic device according to claim 4,
The spectroscopic device, wherein the diffractive element is arranged such that light incident on the diffractive element has a velocity component parallel to the rotation axis. The spectroscopic device according to any one of claims 1 to 5, further comprising:
A λ / 4 plate disposed between the diffractive element and the reflecting member and disposed at a position where the 0th-order diffracted light emitted from the diffractive element is incident and the 0th-order diffracted light reflected by the reflecting member is incident. A spectroscopic device comprising: The spectroscopic device according to any one of claims 1 to 6,
The diffraction element includes a volume hologram layer having a periodic refractive index in a first direction parallel to the grating surface and diffracting incident light, and a second reflecting member disposed on one surface of the volume hologram layer; A spectroscopic device comprising: a reflective volume hologram diffraction grating comprising: a parallel plate that transmits light disposed on the other surface of the volume hologram layer. The spectroscopic device according to any one of claims 1 to 7,
The spectroscopic device, wherein the photodetector includes a plurality of photodetectors, each detecting the diffracted light of a specific order in a different wavelength band. A confocal scanning microscope comprising the spectroscopic device according to claim 1.

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