JPH01102325A - Spectroscope using concave diffraction grating and cylindrical surface mirror - Google Patents

Abstract

PURPOSE:To diffract a light beam spectrally while securing both resolution and brightness and to enable the accurate and easy adjustment of an optical axis, by fixing the relative positions of a concave diffraction grating, a cylindrical surface mirror and a polarizing mirror and by making the concave diffraction grating move linearly. CONSTITUTION:The horizontal component of a light beam emitted from a point light source 1 is converged on a slit S by a cylindrical surface mirror M0 and further the light emitted from the slit S is converged on a sample 2 by a toroidal mirror M3. Meanwhile, the vertical component of said light is reflected by the mirror M0 and a plane mirror M1 with the directional vector in the vertical direction maintained and then falls on a cylindrical surface mirror M2 to be imaged intermediately primarily, and it falls on a concave diffraction grating G. A diffracted light formed by the grating G is dispersed for each wavelength within a vertical plane, and only the light diffracted in the direction of a prescribed diffraction angle beta is converged on the ample 2 and emitted. The emitted light is converged on the sample 2 by a mirror M3. In this way, the light can be diffracted spectrally with both resolution and brightness secured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a spectrometer using a concave diffraction grating and a cylindrical mirror.

[Prior Art/Problems to be Solved by the Invention] Typical conventional spectrometers using concave diffraction gratings are those employing the Roland mount system and the Seya-Namioka mount system. These spectrometers have a structure in which a slit is disposed after IyI of the concave diffraction grating due to the key points of the spectroscopic method.

That is, a spectrometer employing either method requires an entrance slit that opens the incident light to the concave diffraction grating. Using these spectrometers ＾min W? In order to obtain excellent spectral characteristics, it is necessary to narrow down the entrance slit.
As a result, the intensity of light passing through the entrance slit is reduced, resulting in a decrease in brightness. Conversely, if the entrance slit is widened to increase the amount of light that passes through it and make it brighter, the spectral resolution will decrease. As described above, since conventional spectrometers require an entrance slit, there is a problem in that they cannot achieve both the spectral characteristics of resolution and brightness. Furthermore, in order to separate light using a spectrometer, it is necessary to arrange the optical element at a predetermined position with respect to the optical axis (optical axis adjustment) in advance. The conventional method for adjusting the optical axis 'A' is the focus position. 1, a method of determining the position of the optical axis by visually determining the degree of condensation of the zero-order light with high light intensity has been frequently used. With this conventional method, it is not possible to adjust the optical axis using zero-analysis light with low light intensity, and furthermore, the accuracy of the optical axis adjustment is inaccurate due to the evaluation with the naked eye. was there.

The purpose of the present invention is to split light by balancing the spectral characteristics of "simple resolution" and "brightness", which were considered to be contradictory characteristics in conventional spectrometers, and to accurately and easily adjust the optical axis. It is something to do.

[Means for solving problems]

The present invention is a spectrometer using a concave diffraction grating, which includes a cylindrical mirror and a polarizing mirror disposed upstream of the concave diffraction grating on an optical path, and relative positions of the concave diffraction grating, the cylindrical mirror, and the polarizing mirror. and an optical axis adjustment mechanism using a knife and a charging plate. It is characterized by:

[T, 1^ Example] First, the optical arrangement of the glue structure of the present invention shown in FIG.
This will be explained using the t diagram. A long cylindrical mirror MO is installed at a fixed distance J from the point light source 1, and the optical axis of the light emitted from the point light source 1 is set at a fixed distance J from the point light source 1. The baby can be bent towards the bottom of the water. A plane mirror M1 (G light mirror) is provided at a distance Jl from the cylindrical mirror MO, and the optical axis is bent downward by this plane mirror M1. A long cylindrical mirror M2 is installed at a distance of 12 from the plane mirror M1, and a concave diffraction grating G is installed at a distance of 13 from the cylindrical mirror M2, and the optical axis is set at a diffraction angle with respect to the concave diffraction grating G. It is bent upward at an angle of β. Here, the angle ε between the optical axis from the concave diffraction grating G and the horizontal plane is always fixed. An exit slit l-S having a width in the vertical direction is installed at a position 14 m away from the concave diffraction grating G, and a toroidal mirror M3 is installed at a certain distance Jsll from the exit slit S. The axis was returned to horizontal, and the sample (
sag+ple) Set 2.

With the above optical aperture, the horizontal component of the light emitted from the point light source 1 is focused onto the output slit S by the cylindrical mirror MO, and the light source emitted from the output slit S is further directed to the sample 2 by the toroidal mirror M3. The light is focused. On the other hand, the vertical component is reflected by the cylindrical mirror MO and the plane mirror M1 while maintaining the vertical direction vector, and then enters the cylindrical mirror M2, and then forms an intermediate image onto the concave diffraction grating G. incident. The diffracted light diffracted by the concave diffraction grating G is dispersed in the vertical plane for each wavelength, and only the light diffracted in the direction of a predetermined diffraction angle β is focused onto the sample 2 and emitted. Output light is toroidal mirror M3
The light is focused on sample n2 by. The present invention is a device having an optical arrangement ranging from a plane mirror M1 to a toroidal mirror M3.

Next, the mechanical configuration of the spectrometer according to the present invention will be explained using FIG. 2. Plane mirror M1. The cylindrical mirror M2 and the concave diffraction grating G are fixed to the M1 holder 3, the M2 holder 48, and the G holder 5, respectively. M2 holder 4
and the G holder 5 are fixed on the stage 6, and the M1 holder 3 is set on the stage 6 so as to rotate around a rotation axis 7 centered on the plane mirror M1. Here, the M1 holder 3, M2 holder 4, and G holder 5 are rotated so that the plane mirror M1 faces downward and the cylindrical mirror M2 and concave diffraction grating G face upward. stage 6
is connected to the stage 9 so as to rotate around the rotation axis 8 centered on the concave diffraction grating G, and is also rotated around the rotation axis 7 centered on the plane mirror M1 while being sandwiched between the M1 holder 3 and the stage 10. The M1 holder 3 and the stage 10 are connected to each other so that the M1 holder 3 and the stage 10 are connected to each other.

The stage 9 is bound to a G rail 11 that forms an angle of ε with the horizontal axis, and is connected to a ball screw 13 via a nut 12 so as to be linearly driven. - connected to the cable 14; An output slit S is arranged roughly on the optical axis of the diffracted light. The exit slit S can be adjusted backward in the optical axis direction by the linear introducer 15. On the downstream side of the exit slit S,
A toroidal mirror M3 fixed to the M3 holder 16 is installed in order to focus the output light emitted from the output slit S onto the surface of the sample n2.

The tip of a half-angle mechanism hinter arm 17 is inserted and fixed into the rotation @7 of the M1 holder 3 toward the center of rotation, and a center arm support 19 that is pushed toward the center of rotation by a spring 18 is attached to this arm 17. Ru. In addition, stage 6 and stage 10 each have a half-width 14M side arm support.

21 is fixed, and both side arm supports 20°21
Side arms 22 and 23 of equal length are inserted between the center arm support 19 and the half-angle v1 bridge of the plane mirror M1.

Now, the angle of incidence of the cylindrical mirror M2 and the concave diffraction grating G is fixed to a constant angle α, and the relative positions of the plane mirror M1, 81 mirror M2I3 and the concave diffraction grating G are fixed. When the ball screw 13 is rotated in this state, the nut 1
The stage 9 connected to the
The concave diffraction grating G moves linearly with its center of rotation always moving toward the exit slit S in the ri-ray direction U-J. Since the stage 10 is constrained by the M rule 14, the stage 6 moves with rotation in accordance with the movement of the concave diffraction grating G. This rotation angle and moving distance satisfy the m coefficient of the diffraction angle and dispersion (distance from the center of the concave diffraction grating G to the focal point) of the diffracted light. At this time, the half-angle mechanism rotates the plane mirror M1 by half the rotation angle of the stage 6.
Nf12 movement according to rule 14. With the above mechanism, the plane mirror M1 can be generated by only straight II driving of the concave diffraction grating G.
The light reflected by is always incident on the cylindrical mirror M2 and the concave diffraction grating G at a constant angle of incidence, and the diffracted light can always be emitted from the output slit S in a constant direction.

Next, a mechanism for adjusting the optical axis g4 of the above-mentioned spectrometer will be explained using FIG. 3. Optical elements 24 such as mirrors and concave diffraction gratings are mounted in each holder 25 while being held down by clamps 26 . A V7 hole 27 is formed on the clamp 26 at a position corresponding to the center position of the optical element 24 to be mounted, and a knife 30 is inserted into the hole 27 by a linear introducer 29 connected to the flexible shaft 28. Move up and down relative to the surface. When the knife 30 is fully inserted 27, a gap of approximately 100 μm is formed between the knife 30 and the surface of the optical element 24. Furthermore, a photoelectric plate 31 that moves up and down like the knife 30 is installed downstream of the optical element 24 so as to receive reflected light (or diffracted light). A lead 1Q32 for detecting light 11 is connected to this charging plate 31. Now, when the knife 30 is fully inserted 27 and the photoelectric plate 31 is moved to the position where it receives light, if the optical axis passes through the center of the optical element 24, the light passes through F1 below the knife and the photoelectric plate 31
On the other hand, if the optical axis is off, the light will be blocked by the knife 30 and the light f will be detected.
fi flow is not detected. That is, by detecting the light TiI on the optical axis; 11fI, it becomes possible to accurately and easily perform the detection.

Next, the results of an experiment using the above spectrometer will be explained. FIG. 4 shows the light intensity distribution in the width direction (Z) of the output slit for the diffracted light of each wavelength of 21 to 124 people located 33 GJ on the output slit, simulated by the ray tracing method. However, this is jo+Jden+Jz-2
2, On, lx -0,125854m, Us-0,2
65225m~0.531949m, α-87,0°,
β-75,666960°～ 83.549933°(
This is the result when diffraction order: m-1, number 1: d-24001/sw+). It can be seen from this that in the arrangement of this spectroscopic method without an entrance slit, the diffracted light of each wavelength of 21 to 124 people is focused to 9111IP-20μ or less. Note that the efficiency of incident light entering the concave diffraction grating is higher than that of the conventional method of blocking light with an entrance slit, since all light except for light that spreads beyond the size of the concave diffraction grating is incident. It is clear that there is.

In addition, in the above spectrometer, in order to drive the knife, charging board, etc., including various WI adjustments of optical elements, this v1
Even if the entire structure is housed in a vacuum chamber, various adjustments can be made from outside the chamber.

[Effect of invention]

As explained above, the present invention has a configuration that eliminates the need for an entrance slit by combining a concave diffraction grating and a cylindrical mirror, so the light from the light source is no longer blocked by the entrance slit as in conventional spectrometers. , thus the brightness can be increased.

Furthermore, since the configuration is such that the degree of convergence of the diffracted light at the exit slit is n, high resolution can be achieved at the same time. In addition, we have provided a drive IS that automatically converges the diffracted light onto the exit slit by moving the concave diffraction grating ixa, making it possible to perform spectroscopy just by linearly driving the concave diffraction grating. . This fJJ mechanism can improve the accuracy of movement and rotation of the optical element. Furthermore, the optical axis adjustment mechanism using a knife and a photoelectric plate makes it possible to accurately and easily adjust the optical axis.

In particular, the present invention has a sink IJ that has an IT continuation spectrum ranging from vacuum ultraviolet to the hard
'1fi is applied to the spectroscopy of l-ron radiation (SR).

■ Since there is no entrance slit, the light source point can be regarded as a conventional entrance slit, making it possible to disperse highly directional SR with high efficiency. It is particularly suitable for spectroscopy of highly directional angular dilator light.

■ Spectroscopy in the vacuum ultraviolet region is possible because spectroscopy can be performed in vacuum.

■ The angle of incidence between the concave diffraction grating and the cylindrical mirror is 87° to 8.
9° toshi, iM fiN=600.1200 or 24
By using a concave diffraction grating of 0.00 J/am, it becomes possible to perform spectroscopy of light with wavelengths ranging from the sky ultraviolet to the soft X-ray region.

■ Since the distance from the light source point to the cylindrical mirror can be freely selected to be several tens of meters, it is usually 10 meters or more.
A monochromator can be installed at any position on the 40 m long synchrotron radiation beam line. Furthermore, since the distance from the cylindrical mirror to the concave diffraction grating can be set to several tens of α, the spectrometer can be compact in size.

[Brief explanation of the drawing]

Figures 1 to 3 (a) and (b) are diagrams showing an embodiment of the present invention, in which Figure 1 is an optical layout diagram of a spectrometer;
FIG. 2 is a schematic configuration diagram of the spectrometer, FIG. 3(a) is a side view of the optical axis adjustment mechanism of the spectrometer, and FIG. 3(b) is a longitudinal sectional view thereof. FIGS. 4(a) to 4(f) are diagrams showing the results of experiments conducted using the above-mentioned spectrometer, and are diagrams showing the light intensity distribution on the output slit at various wavelengths. G: concave diffraction grating, Ml: polarizing mirror (plane mirror), M2: cylindrical mirror, S: output slit, 3o: knife, 31: photoelectric plate.

Claims (1)

[Claims] A spectrometer using a concave diffraction grating, comprising a cylindrical mirror and a polarizing mirror disposed upstream of the concave diffraction grating on the optical path, and fixed relative positions of the concave diffraction grating, the cylindrical mirror, and the polarizing mirror. It is equipped with a drive mechanism that causes the concave diffraction grating to linearly move to automatically converge the diffracted light onto the exit slit, and an optical axis adjustment mechanism that uses a knife edge and a photoelectric plate. A spectrometer that uses a characteristic concave diffraction grating and cylindrical mirror.