JPH06221922A - Double stage spectometer - Google Patents

Abstract

PURPOSE:To provide a downsized double stage spectrometer requiring no synchronizing mechanism by reflecting the light emitted through a slit of a spectrometer back to the slit thereby transmitting the light again through the spectrometer. CONSTITUTION:Light emitted from a light source 1 passes through a slit 2 and a slit 6 passes only such light as having a specific wavelength. One of the lenses 7 converts the light passed through the slit 6 into a parallel light which is reflected on a right angle prism 8 whereas the other of the lenses 7 passes the reflected light from the right angle prism 8 through the slit 6 again. Alternatively, a corner cube prism 9 is used in place of the right angle prism 8 and the light reflected on the corner cube prism 9 is passed through the slit 6 again.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-stage spectroscope which allows light emitted from a light source to pass through the spectroscope twice.

[0002]

2. Description of the Related Art Next, the structure of a conventional two-stage spectrometer is shown in FIG.
Shown in. In FIG. 6, 20 and 30 are spectroscopes, 11 is a light source, 12 is a slit, 13 is a concave mirror, 14 is a diffraction grating,
15 is a concave mirror, 16 is a slit, 22 is a slit, 23
Is a concave mirror, 24 is a diffraction grating, 25 is a concave mirror, and 26 is a slit. The spectroscope 20 is configured with 12 to 16 in FIG.
The spectroscope 30 is constituted by 22 to 26 in FIG.

In FIG. 6, the light emitted from the light source 11 enters the spectroscope 20 through the slit 12, is reflected by the concave mirror 13, and enters the diffraction grating 14. The diffraction grating 14 is a concave mirror 13.
Of the incident light from the light source 11 to the spectroscope 20 and outputs only a specific wavelength component determined by the angle with respect to the vertical axis of the diffraction grating 14 to the concave mirror 15. The reflected light of the concave mirror 15 is emitted from the slit 16.

Light emitted from the slit 16 is emitted from the slit 2
The light enters the spectroscope 30 from 2 and is reflected by the concave mirror 23 to enter the diffraction grating 24. The diffraction grating 24 is used in the spectroscope 20.
In the same manner as the diffraction grating 14 of, the incident light is reflected at different angles depending on the wavelength, and only the specific wavelength component determined by the angle of the diffraction grating 24 with respect to the vertical axis is emitted to the concave mirror 25. The reflected light of the concave mirror 25 is emitted from the slit 26.

With such a configuration, the spectroscope 20 and the spectroscope 3
By setting the angles of the diffraction grating 14 and the diffraction grating 24 so that the transmitted wavelengths of 0 are equal, the light source 1
Only the specific wavelength component of the light emitted from the spectroscope 3
It can be taken out from the slit 26 of 0.

Next, the spectrum of light transmitted through FIG. 6 will be described with reference to FIG. In FIG. 7, 31 is the spectrum of the light emitted from the light source 11, 32 is the spectrum of the light emitted from the slit 16 of the spectroscope 20, and 33 is the spectrum of the light emitted from the slit 26 of the spectroscope 30.

Since the spectrum 32 is obtained by extracting only a specific wavelength component from the light emitted from the light source 11 by the spectroscope 20, the spectrum 32 has a narrower spectrum width than the spectrum 31 of the light emitted from the light source 11 and has a high monochromaticity. Has become. Further, since the spectrum 33 is obtained by extracting only a specific wavelength component from the light emitted from the spectroscope 20 by the spectroscope 30, the spectrum width is narrower than the spectrum 32 of the spectroscope 20, and the spectrum has high monochromaticity. There is.

As described above, in the two-stage spectroscope in which the light from the light source is transmitted through the spectroscope twice, it is possible to extract a spectrum having a higher monochromaticity as compared with the case where only one stage of the spectroscope is used.

[0009]

In the configuration of FIG. 6, the number of parts and the optical path length are doubled as compared with the case where only one stage of the spectroscope is used. Therefore, the overall size is large and the cost is high. In addition, the spectroscope 20 and the spectroscope 3
Since the transmission wavelength of 0 must be completely the same, it is necessary to control the angles of the diffraction grating 14 and the diffraction grating 24 separately. When sweeping the wavelength, the angles of the diffraction grating 14 and the diffraction grating 24 are A complex synchronization mechanism is required because the two spectrographs must be rotated in a relationship such that they transmit the same wavelengths as each other.

Further, if the grooves formed on the surfaces of the diffraction grating 14 and the diffraction grating 24 are slightly inclined from the vertical axis, the position of the light emitted from the slit 16 or the slit 26 moves up and down as the rotation occurs. Change. Further, even if the angle of the diffraction gratings 14 and 24 with respect to the horizontal plane slightly changes due to temperature fluctuation and the like, the position of the light emitted from the slits 16 and 26 also fluctuates up and down.

The positional variation of the light emitted from the slit 26 is
It is the sum of the positional fluctuations generated by the spectroscope 20 and the positional fluctuations generated by the spectroscope 30, which is larger than the case where only one stage of the spectroscope is used. Therefore, the spectroscope 30
When the output light of (1) is focused on a component having a small light receiving area such as an optical fiber, the position of the optical fiber must be readjusted each time the wavelength is changed or the temperature is changed.

According to the present invention, there is provided a reflecting means for re-incident the light emitted from the slit of the spectroscope from the same slit, and the light is transmitted through the spectroscope twice. It is an object of the present invention to provide a two-stage spectroscope that is small in size, low in cost, does not require a synchronization mechanism, and has little positional fluctuation of light emitted from the spectroscope.

[0013]

In order to achieve this object, according to the present invention, a light having a specific wavelength is emitted from the slit 2 which is incident on the light emitted from the light source 1 and the light emitted from the light source 1 which is incident on the slit 2. In a dispersive spectroscope having an exit slit 6, a lens 7A that makes the exit light from the slit 6 incident into parallel light, a right-angle prism 8 that reflects the parallel light from the lens 7A, and a reflection from the right-angle prism 8 A reflecting means 7 having a lens 7B that re-enters the light into the slit 6 is provided. Alternatively, the reflecting means 7 re-enters the lens 7A that makes the light emitted from the slit 6 parallel light, the corner cube prism 9 that reflects the parallel light from the lens 7A, and the reflected light from the corner cube prism 9 to the slit 6 again. It has a lens 7B for making it incident.

[0014]

Next, the structure of the two-stage spectroscope according to the present invention will be described with reference to FIG. In FIG. 1, 1 is a light source, 2 is a slit, 3 is a concave mirror, 4 is a diffraction grating, 5 is a concave mirror, 6 is a slit, and 7 is a reflecting means. 2 to 6 in FIG.
Make up. Next, the operation of FIG. 1 will be described with reference to FIG. Light emitted from the light source 1 enters the spectroscope 10 from below the center of the slit 2, is reflected by the concave mirror 3, and enters the diffraction grating 4.

The diffraction grating 4 reflects the incident light at different angles depending on the wavelength, and of the incident light to the spectroscope 10, only a specific wavelength component determined by the angle with respect to the vertical axis of the diffraction grating 4 is emitted to the concave mirror 5. To be done. The reflected light from the concave mirror 5 is emitted from above the center of the slit 6. The light emitted from the slit 6 is reflected by the reflecting means 7 and again enters the spectroscope 10 from below the center of the slit 6.

The light re-incident from the slit 6 passes through the diffraction grating 4 again and is emitted from above the center of the slit 2. Since the light emitted from the slit 2 is transmitted through the spectroscope 10 twice, a spectrum having a higher monochromaticity can be obtained as in the case where only one stage of the spectroscope is used, as in FIG.

[0017]

EXAMPLE Next, the structure of the reflecting means 7 will be described with reference to FIG. In FIG. 2, 6 is a slit, 7A and 7B are lenses, and 8 is a right-angle prism. In FIG. 2, the light emitted from the slit 6 is collimated by the lens 7A, reflected by the rectangular prism 8 and further incident on the spectroscope 10 by focusing on the slit 6 by the lens 7B.

Next, the positions of the emitted light and the incident light on the slit 6 when the reflecting means of FIG. 2 is provided will be described with reference to FIG. In FIG. 2, since the light from the slit 6 is reflected by the right-angle prism 8, the light emitted from the position A in FIG. 3, the light emitted from the position A, the light emitted from the position A, and the light emitted from the position C in FIG. The light emitted from the position K and the light emitted from the position D re-enters the position K.

As described above, the light emitted from the position far from the center of the slit 6 is incident on the position close to the center of the slit 6. Therefore, even if the position of the outgoing light changes due to the rotation because the groove of the diffraction grating 4 is inclined, the position of the outgoing light from the slit 2 becomes constant because the re-incident position moves in the opposite direction. The position variation of the emitted light is reduced.

Next, the structure of another embodiment of the reflecting means 7 will be described with reference to FIG. Reference numeral 9 in FIG. 4 denotes a corner cube prism, and the others are the same as those in FIG. In FIG. 4, a corner cube prism 9 is arranged instead of the rectangular prism 8 of FIG. The corner cube prism 9
For example, SPINDLER &HOYER's thing can be used.

Next, the positions of the emitted light and the incident light on the slit 6 when the reflecting means of FIG. 4 is provided will be described with reference to FIG. Since the light from the slit 6 is reflected by the corner cube prism 9 in FIG. 5, the light emitted from the position A in FIG. 5 is emitted to the position S, the light emitted from the position A to the position S, and the light emitted from the position C. The emitted light re-enters the position S, and the light emitted from the position D re-enters the position S. That is, as in the case of FIG. 3, the light emitted from the position far from the center of the slit 6 enters the position close to the center of the slit 6. Therefore, the position variation of the emitted light is reduced.

In FIG. 3, since the right-angle prism 8 is used, the left and right of the outgoing light and the re-incident light are interchanged, whereas in FIG. 5, since the corner cube prism 9 is used, the outgoing light and the re-incident light are re-incident. The difference is that the left and right sides of the light are not interchanged. For this reason, FIG. 2 shows an addition-dispersion type two-stage spectrometer.
Is a difference dispersion type two-stage spectroscope.
And the configuration of FIG. 4 is used properly.

In this embodiment, the case where the spectroscope is a Czerny-Turner type has been described, but a spectroscope having another optical arrangement such as a Littrow type may be used. A lens may be used instead of the concave mirrors 3 and 5.

[0024]

According to the present invention, the reflecting means 7 for re-incident the light emitted from the slit 6 from the same slit 6.
Since the light is transmitted through the spectroscope 10 twice, the same spectroscope is used in the first and second stages, and the control for matching the transmission wavelengths of the two spectroscopes and the same wavelength are used. Therefore, it is possible to provide a spectroscope having a small structure and a low cost, because a structure for synchronizing the structure for sweeping while keeping the above is unnecessary. Further, since the rectangular prism 8 or the corner cube prism 9 is used for the reflecting means 7, it is possible to provide a spectroscope in which the position variation of the light emitted from the spectroscope 10 is small.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a two-stage spectroscope according to the present invention.

2 is a configuration diagram of an embodiment of a reflecting means 7 in FIG.

FIG. 3 is a diagram showing positions of emitted light and incident light on a slit 6 when the reflection means of FIG. 2 is provided.

4 is a configuration diagram of another embodiment of the reflection means 7 of FIG.

5 is a diagram showing the positions of outgoing light and incident light on the slit 6 when the reflecting means of FIG. 4 is provided.

FIG. 6 is a configuration diagram of a conventional two-stage spectroscope.

7 is a diagram showing a spectrum of light passing through FIG.

[Explanation of Codes] 1 light source 2 slit 3 concave mirror 4 diffraction grating 5 concave mirror 6 slit 7 reflecting means 7A / 7B lens 8 right angle prism 9 corner cube prism 10 spectroscope

Claims (2)

[Claims] 1. A slit into which light emitted from a light source (1) is incident.
(2) and the light emitted from the light source (1) incident on the slit (2), the light emitted from the slit (6) is detected in a dispersive spectrometer equipped with a slit (6) that emits light of a specific wavelength. First incident light to make parallel light
Right angle prism that reflects parallel light from the first lens (7A) and the second lens (7A)
A two-stage spectroscope comprising (8) and a reflecting means (7) having a second lens (7B) for re-incident the reflected light from the rectangular prism (8) on the slit (6). 2. The reflecting means (7) comprises a first lens (7A) for collimating the light emitted from the slit (6) and a corner cube for reflecting the collimated light from the first lens (7A). Slit the reflected light from the prism (9) and the corner cube prism (9)
2. The two-stage spectroscope according to claim 1, further comprising a second lens (7B) which re-enters (6).