JPS62261037A - Cars optical apparatus - Google Patents

Abstract

PURPOSE:To facilitate the adjustment of optical axis while enhancing the intensity of a signal with a higher spatial resolution, by making an excitation light and a Stokes' light as transmitted through and reflected with a dichroic mirror respectively incident into a condenser lens being kept tight in the interface between the two lights. CONSTITUTION:An excitation light 2 generated from an excitation light source 1 is transmitted through a dichroic mirror 10 while a Stokes' light 5 generated from a Stokes' light source 4 is reflected therewith 10 to be incident into a condenser lens 7. A knife edge 11 as a device for shielding excitation lights and a knife edge 12 as device for shielding Stokes' lights are positioned and adjusted to be vertical to optical paths of the excitation light 2 and the Stokes' light 5 and both the luminous fluxes are made parallel each other to be incident into the condenser lens 7 being kept tight in the interface therebetween so that a crossing angle will be very limited between the excitation light 2 and the Stokes' light 5 at the measuring point 8. This generates a kerr's light with a relatively large intensity of signal and with a high spatial resolution.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an optical device for performing cursing, which is a type of Raman spectroscopy, that is, a cursing optical device.
In particular, the present invention relates to a Curse optical device suitable for easily increasing the spatial resolution of a measurement region.

[Conventional technology]

One type of optical analysis device that has recently been rapidly developed and researched is the Kaas optical device.

The curse optical device is an optical device for performing curse (CAR3).

The basic principle of the curse and the curse optical device for implementing the curse will be explained below.

CAR3 is coherent anti-Stokes Raman spectroscopy (C.

herent Anti-3tokes Raman
5 pectroscopy), which is a type of Raman spectroscopy. Raman spectroscopy is a spectroscopic analysis method that uses the Raman effect, and the Raman effect is
This is the effect that when a substance is irradiated with light, light with a different wavelength from that wavelength is scattered from the substance. The scattered light is
Irradiation light (excitation light) is light based on the molecular vibrations of substances.
Scattered light on the longer wavelength side is called Stokes Raman scattered light, and that on the shorter wavelength side is called anti-Stokes Raman scattered light. In normal Raman spectroscopy, Stokes Raman scattered light is observed, but depending on the measurement target, it may be difficult to observe Stokes Raman scattered light. For example, when measuring the structure of a combustion flame in a coal combustion furnace, etc., unstable chemical species called radicals exist in the flame, and when they are irradiated with strong light, they are excited and It accompanies luminescence when returning to the state. This is called fluorescence, and is observed at longer wavelengths than the irradiated light. Therefore, when ordinary Raman spectroscopy is used for flame measurement, excitation light generates fluorescence and Stokes Raman scattered light cannot be observed well.

Therefore, in flame measurement, it is necessary to observe and measure anti-Stokes Raman scattered light that is not affected by fluorescence, but in normal Raman spectroscopy, anti-Stokes Raman scattered light is It has an intensity of only about 1/10" of the scattered light and is very weak, so the light from the flame itself, which is the measurement target, becomes background light and is very difficult to detect.

On the other hand, the curse is an effective measurement method for measuring objects such as the above-mentioned flame.

The curse will be explained in more detail below.

A substance (natural frequency = Ω) receives excitation light (frequency = ω1, wavelength = λI) and light with the same wavelength as the Stokes Raman scattered light of the material, that is, Stokes light (frequency = ω2, wavelength = λ2)
), coherent (spatially and temporally aligned) anti-Stokes Raman scattered light (frequency = ω1, wavelength - λ) is generated. . The spectroscopic analysis method using this light is called CARSE (CAR5), and this light is called CARSE light (or CARSE signal).

Note that the vibration frequencies Ω, ω1. ω2. Regarding ω, the following relational expression holds true.

ω2=ω, -Ω ω3=ω, +Ω! , ω2+ω3=2ω From this equation, the wavelength λ1. Regarding λ2 and λ, the following relational expression holds true.

λ,=λ,λt/(2λ2−λ,)・−・−・<11The curse light is anti-Stokes Raman scattered light, so it is not affected by fluorescence, and since it is coherent light, it can be efficiently Can focus light. Furthermore, the curse light is different from the Stokes Raman scattered light obtained by ordinary Raman spectroscopy.
Since the intensity is 10" to 10' times higher, the influence of the fluorescent light emitted by the object to be measured (flame, etc.) is also small.

As mentioned above, the curse optical device that uses cursed light is one of the effective measurement methods, especially for measurement targets such as flames, and spectrally analyzes the cursed light and uses its spectral waveform to detect Information such as the concentration, temperature, or pressure of a substance can be easily obtained.

Such a Curse optical device is described, for example, in Seventeenth Aerospace Sciences Meeting, 79-0083 (1797), pp. 2-4 (17
th AHROSPACB SCI [! NCII:S
MEETING 79-0083 (1979) pp2
-4). In this Seventeenth Aerospace Science Meating, there are descriptions regarding the General CARS optical system, the Colinear CARS optical system, and the Box CARS optical system.

Also, American Chemical Society Symposium Series Laser Probes Compassion Applications (1980) page 24, Figure 2 (Am, Chem, Soc, Sy+++p, Set
.

La5er Probes for combust
hion applications (1980) p.
Fig. 2) on page 24 shows a practical optical device of the collinear curse optical system.

And also, Proceedings Society Photo
Instruments Engineering (1978) No. 15
Volume 8, page 69, Figure 2 (Proc, Soc, Ph.

t, Opt, Instrum, Eng, (1978
) Vol. 158, pp. 69, Fig. 2) shows a practical optical device of the box curse optical system.

The General Curse optical system is an optical system that is generally used to explain Curse optical systems, but has not been put into practical use for reasons described later.

Next, the measurement principle of the Curse optical system will be explained by taking this General Curse optical system as an example.

The General Curse optical system is an optical system as illustrated in FIG. Stokes light 5 is obtained by pumping the light source 4. Usually, a high-power laser such as a YAG laser is used as the excitation light source. In particular, the second harmonic, 532
Visible light with a wavelength of nanometers is often used. A wavelength-tunable dye laser is used as the Stokes light source.

For example, when generating curse light from nitrogen molecules, the Stokes light source must use light with a wavelength corresponding to the Stokes Raman scattered light of nitrogen molecules, and the dye laser has an oscillation center wavelength of 607.3 nanometers. Adjust and use.

Then, the excitation light 2 and the Stokes light 5 are made to enter the condenser lens 7 through a suitable optical member such as a prism 6.6. This condenser lens 7 directs the excitation light 2 and Stokes light 5 to the focal point of the condenser lens 7, that is, to the measurement point 8.
When narrowed down to , a cursed light 9 is generated with an intensity and direction that satisfies a phase matching condition (described later). As in the above example, excitation light 2 with a wavelength of 532 nm and Stokes light 5 with a wavelength of 607.3 nm are applied to nitrogen molecules.
In the case of It measures the concentration of nitrogen, temperature, etc. at a measurement point in a gas (or gas in a container, etc.).

Next, the phase matching condition will be explained. The phase matching condition is expressed by the following vector equation that holds true for all Curse optical systems.

2 Y= I) + C−−−−−−・−・−・・・−
−−−1−・−・−−−−(2) Here, Y is the wave number vector of the excitation light, D is the wave number vector of the Stokes light, and C
is the wave number vector of the curse light.

What the above equation (2) means is that the direction of the curse light generated from the overlap of the two laser beams, the excitation light and the Stokes light, satisfies the above equation (2). .

When the intensity of the excitation light and the curse light are constant, the signal intensity of the cursed light changes depending on the intersection angle between the excitation optical axis and the Stokes optical axis, and increases as the intersection angle becomes smaller. It is said that curse light will not occur unless there is an intersecting angle.

Furthermore, in order to increase the signal strength of the cursed light as much as possible, it is desirable to bring the intersection angle as close to zero as possible, that is, to bring the two optical axes as close as possible so that they overlap. However, if the excitation light and Stokes light overlap in areas other than the measurement point, curse light will be generated from the entire area where both of these lights overlap, resulting in a decrease in the spatial resolution of the measurement point. Become.

[Problem that the invention seeks to solve]

As mentioned above, in order to obtain high signal strength and high resolution in the Curse optical device,
On the one hand, in order to increase the signal strength, the excitation and Stokes optical axes should be brought as close to zero as possible, preferably overlapping, and on the other hand, in order to increase the resolution, the excitation and Stokes beams should be moved away from the measurement point. Therefore, it is required to simultaneously satisfy two seemingly mutually contradictory requirements: to keep the distance as far as possible.

By the way, the phase matching condition of the General Curse optical system is expressed as a vector as shown in FIG.

In FIG. 5, θ is the intersection angle between the excitation light 2 and the Stokes light 5 at the measurement point. The direction in which the curse light 10 is generated is the direction that satisfies the phase matching condition, that is, the direction of the vector C in FIG. 5, but it is very difficult to detect this direction. It is also very difficult to superimpose the excitation light 2 and the Stokes light 5 at the measurement point.

Therefore, although the General Curse optical system explains the concept of the Curse optical system very well, it has not been put to practical use until now because it is difficult to satisfy the phase matching condition.

In addition, the collinear curse optical system is an optical system as illustrated in FIG. The Stokes light source 4 is bombed by using the 3D light source 4 to obtain the Stokes light 5. Then, the excitation light 2 is made to enter the condenser lens 7 via the prism 6 and the dichroic mirror IO. Further, the Stokes light 5 is made to enter the condenser lens 7 in a state where it is superimposed on the excitation light 2 by the dichroic lens 10. When the excitation light 2 and the Stokes light 5 are condensed by the condenser lens 7 to the focal point of the condenser lens 7, that is, to the measurement point 8, curse light 9 is generated from there in a direction that satisfies the phase matching condition. A feature of this collinear curse optical system is that two beams of excitation light 2 and Stokes beam 5 are combined into one beam by a dichroic mirror 10. Therefore, the phase matching condition of the collinear curse optical system is expressed as a vector as shown in FIG. That is, the intersection angle θ in FIG. 5 is zero, and the direction in which the curse light 9 is generated is the same as the direction of the excitation light 2 and the Stokes light 5, making it easy to detect the curse light 9. becomes. In addition, the collinear curse optical system is easy to adjust the optical system because it is only necessary to adjust the optical axis of one light beam, and the area where the excitation light 2 and the Stokes light 5 overlap is large. Therefore, the signal strength of the curse light 9 is high. However, since the area where the curse light 9 is generated becomes larger, there is a problem that the spatial resolution becomes lower.

Furthermore, the boxcurse optical system is an optical system as illustrated in FIG.
Half mirrors 3, 3 are placed on the optical path of the pump, and a part of the excitation light 2 is used to pump the Stokes light source 4 to obtain Stokes light 5. The Stokes light 5 is reflected by the dichroic mirror 10 and enters the condenser lens 7. Moreover, about 1/2 of the remaining excitation light 2 that was not used for excitation of the Stokes light source 4 is reflected by the half mirror 3, transmitted through the dichroic mirror 10, and superimposed on the Stokes light 5. Luminous flux (hereinafter referred to as [polymerized luminous flux 2.5])
and enters the condenser lens 7. On the other hand, the excitation light 2
The other half of the light passes through the half mirror 3, passes through the prism 6, and enters the condenser lens 7 in parallel with the superposed light beam 2.5. When the excitation light 2 and the superimposed light beam 2.5 are condensed by the condenser lens 7 to the focal point of the condenser lens 7, that is, to the measurement point 8, the excitation light 2 at the measurement point 8 becomes 1/2+1/2=1. And this measurement point 8
, the curse light 9 is generated in a direction that satisfies the phase matching condition. The phase matching condition of the boxcurse optical system is the seventh
The vector is displayed as shown in the figure. That is, curse light 9
will be on the side of the excitation light 2 that is not superimposed with the Stokes light 5, so it is not difficult to detect the curse light 9. Note that in the box curse optical system, half (1/2) of the excitation light 2 and the Stokes light 5 are superimposed not only at the measurement point but also within the superposed light beams 2 and 5, so that curse light is generated. .

However, the direction in which this cursed light comes out is different from the direction in which the cursed light 9 generated at the measurement point comes out, since it is partially lost in the direction of the superposed light beams 2 and 5. Therefore, there is no problem in measuring the cursed light 9.

In this boxcurse optical system, the measurement point is the focal point of the condenser lens 7 where the excitation light 2 and the superposed light beam 2.5 overlap, so the spatial resolution is high. However, there are problems in that the signal strength is weak, about 1/5 of that of a collinear curse optical system, and it is also very difficult to adjust the optical axis.

The present invention has been made in view of the problems of the prior art as described above, and compensates for the drawbacks of the collinear curse optical system and the box curse optical system, which are practical curse optical devices, and also takes advantage of the respective advantages. More specifically, it is an object of the present invention to provide a curse optical device that has a high spatial resolution (with a relatively strong signal strength between the signal strength of a collinear curse optical system and that of a box curse optical system, and a relatively strong optical The object of the present invention is to provide a Curse optical device in which axis adjustment can be easily performed based on a collinear Curse optical system, which is the simplest among Curse optical devices.

[Means for solving problems]

Means for solving the above problems will be explained below using FIG. 1 corresponding to the embodiment.

The Kerse optical device of the present invention includes an excitation light source 1 that generates excitation light 2, a Stokes light source 4 that generates Stokes light 5, and is disposed at the intersection of the excitation light 2 and Stokes light 5, and the excitation light a dichroic mirror 10 that transmits either Stokes light 5 or Stokes light 5 and makes the transmitted one luminous flux parallel to the other reflected luminous flux, and the dichroic mirror 10 and the measurement point. 8,
In the Curse optical device, the excitation light source 1 and the dichroic mirror 10 are combined with a condensing lens 7 that narrows the luminous flux of the excitation light 2 and the Stokes light 5 that have passed through the dichroic mirror IO to a measurement point 8. An excitation light shield 11 is provided between the Stokes light source 4 and the dichroic mirror 10 to adjust the area of incidence of the excitation light 2 on the dichroic mirror 10. By providing a Stokes light shield 12 that adjusts the incident area on the color mirror 10, the two light beams 11.1 are made parallel by the dichroic mirror 10.
2 can be placed closely adjacent to each other.

[For production]

In the curse optical device according to the invention with the above-mentioned characteristics:
As shown in FIG. 1, either the excitation light 2 generated by the excitation light art 1 or the Stokes light 5 generated by the Stokes light source 4 enters the dichroic mirror from the back side of the dichroic mirror 10. The other beam passes through the dichroic mirror, and the other beam enters from the surface side of the dichroic mirror and is reflected by the surface of the dichroic mirror. and,
The dichroic mirror 10 is arranged so that the light beam transmitted through the dichroic mirror and the light beam reflected by the dichroic mirror enter the condenser lens 7 with their optical axes parallel to each other. Therefore, the excitation light shield 11 and the Stokes light shield 12
When adjusting the area of incidence of the excitation light 2 and Stokes light 5 on the dichroic mirror 10 by If the excitation light shield 11 and the Stokes light shield 12 are adjusted so that the regions are adjacent (in close contact) with each other without any gaps, the respective luminous fluxes of the excitation light 2 and the Stokes light 5 will be parallel to each other and their The light enters the condenser lens 8 while keeping the boundary surfaces in close contact with each other. Therefore, the excitation light 2 and the Stokes light 5 do not overlap up to the focal point of the condenser lens 7, that is, the measurement point 8, and the intersection angle between the excitation light 2 and the Stokes light 5 at the measurement point 8 is extremely small.

As a result, the generated curse light has a relatively large signal intensity and a high spatial resolution.

〔Example〕

Embodiments of the curse optical device according to the present invention will be described below with reference to the drawings. Note that the same elements as in each of the conventional curse optical systems shown in FIGS. 2 to 4 will be described using the same reference numerals.

FIG. 1 is a diagram showing a first embodiment of the Kurth optical device according to the present invention, in which an excitation light source 1 generates a laser beam having a wavelength λ = 532 nanometers as excitation light 2. The excitation light 2 is formed from a light beam having a circular cross section. A half mirror 3°3 is placed on the optical path of excitation light 2 emitted from an excitation light source 1. A portion of the excitation light 2 reflected by the half mirrors 3, 3 is used to pump the Stokes light source 4, thereby obtaining Stokes light 5 consisting of a light beam having a circular cross section.

Now, assuming that the measurement target is nitrogen molecules, the wavelength λ2 of the Stokes light 5 is adjusted to λ2=607.3 nanometers. The remaining part of the excitation light 2 used for pumping the Stokes light 5 is changed in direction by the prism 6 and is made to enter the back side of the dichroic mirror 10. This dichroic mirror 10 is arranged at a 45 degree inclination with respect to the optical path of the excitation light 2 and the Stokes light 5 at a portion where the excitation light 2 and the Stokes light 5 intersect perpendicularly, as will be described later. , most of the excitation light 2 with a wavelength of 532 nm is transmitted, and most of the Stokes light with a wavelength of 607.3 nm is reflected. Therefore, the luminous fluxes of the excitation light 2 and the Stokes light 5 that have passed through the dichroic mirror 10 become parallel and proceed in the direction of the condenser lens 7. A knife 11 as an excitation light shield is provided between the prism 6 and the dichroic mirror 10 so that its position can be adjusted in a direction perpendicular to the optical path of the excitation light 2. By adjusting , the area of incidence of the excitation light 2 onto the dichroic mirror 10 can be adjusted. This dichroic mirror 1
The excitation light 2 incident on the dichroic mirror 10 passes through the dichroic mirror 10, enters the condenser lens 7, and is condensed at the focal point of the condenser lens 7, that is, at the measurement point 8. On the other hand, the Stokes light 5 generated by the Stokes light source 4 is transferred to the excitation light 2.
The light is made to enter the surface side of the dichroic mirror 10 from a direction perpendicular to . The Stokes light source 4 and the dichroic mirror 1
0, a knife 12 serving as a blocker for Stokes light is provided so that its position can be adjusted in a direction perpendicular to the optical path of the Stokes light 5. By adjusting the position of this knife 12, the Stokes light 5 can be The area of incidence on the dichroic mirror 10 can be adjusted. This dichroic mirror 1
The Stokes light 5 incident on the dichroic mirror 10 is reflected on the surface of the dichroic mirror 10, enters the condenser lens 7, and is condensed at the focal point of the condenser lens 7, that is, at the measurement point 8.

The excitation light 2 and the Stokes light 5 are transmitted through the condenser lens 7.
are superimposed at a measurement point 8, and at this measurement point 8, curse light 9 of nitrogen molecules to be measured is generated.

The wavelength of this nitrogen molecule curse light 9 is 473.3 nanometers. This curse light 9 is made to enter the light receiving lens 13 together with the excitation light 2 and the Stokes light 5. The excitation light 2 and Stokes light 5 that have passed through the light receiving lens 13 are reflected laterally by the dichroic mirror 14, and the curse light 9 that has passed through the dichroic mirror 14 is
The light enters the spectrometer 15 and is analyzed.

By the way, the dichroic VT10 that transmits the excitation light 2 and reflects the Stokes light 5 does not transmit 100% of the excitation light 2 as described above, and also reflects 100% of the Stokes light 5. Do not mean.

That is, a part of the excitation light 2 that has entered the dichroic mirror 10 is reflected and becomes reflected leakage light 2a, and a part of the Stokes light 5 that has entered the dichroic mirror 10 is transmitted and becomes transmitted leakage light 5a. .

In this embodiment, these reflected leakage lights 2a
And the transmitted leakage light 5a is projected onto a semi-transparent screen 16 arranged perpendicular to the optical axis of both,
The structure is such that the overlapping state of the excitation light 2 and the Stokes light 5 that have passed through the dichroic ray 10 can be easily observed.

In an embodiment of the Kurth optical device according to the invention with the above-mentioned configuration, the knives 11 and 12 are first placed in a retracted position 1) in which they do not protrude into the optical path of the excitation light 2 and the beam light 5. pt, the optical axis can be easily adjusted in the same manner as the collinear curse optical system described above. In this state, when the excitation light 2 and the Stokes light 5 are condensed to the measurement point 8 by the condenser lens 7, the curse light 9 generated at the measurement point 8 is absorbed by the condenser lens 7 as in the collinear curse optical system. It will appear on the optical axis l. At this time, the central axes of the respective luminous fluxes of the excitation light 2 and the Stokes light 5 are also on the optical axis l. That is, the phase matching conditions at this time are similar to those shown in the vector diagram of the collinear curse optical system in FIG. 6. Further, at this time, the projected shape of the reflected leakage light 2a and the transmitted leakage light 5a on the screen 16 is as follows:
They completely overlap each other. Next, while observing the cursed light 9 appearing on the optical axis with the spectroscope 15, the knives 11 and 12 are moved to the retreated position p++p.
Protruding position ρ3 from t. When the excitation light 2 and the Stokes light 5 are gradually projected into the optical paths toward ρ4, the positions of the center lines of the respective luminous fluxes of the excitation light 2 and the Stokes light 5 and the curse light change depending on the amount of projection. The direction in which the curse light 9 is generated gradually moves away from the optical axis of the condenser lens 7, and the direction in which the curse light 9 is generated gradually shifts toward the direction of the excitation light 2. On the other hand, the knife blades 11 and 12 are in a protruding position from the retracted position tp+, pz! '31 pa, the projected shape of the reflected leakage light 2a and the transmitted leakage light 5a that overlapped on the screen 16 gradually reduces the overlapping area.

This situation can be easily confirmed by observing the translucent screen 16 from the direction of arrow AA'. As shown in FIG. 8, when a state is observed in which the projected shapes of the reflected leakage light 2a and the transmitted leakage light 5a are approximately semicircular, and the overlapping area of the two is O, that is, the When it is confirmed that the knives 11 and 12 have reached the required protrusion position J)z+94, the protrusion of both is stopped. At this time, also on the surface of the dichroic mirror 10, the passage area of the excitation light 2 and the reflection area of the Stokes light 5 are in contact with each other on their boundary line. At this time, the cross-sectional area of the excitation light 2 light flux and the Stokes light 5 light flux that enter the condenser lens 7 is approximately 172 times the original light flux, and their boundary surfaces are adjacent to each other without any gap. It turns out. In this state, the excitation light 2 and the Stokes light 5 do not overlap each other until they reach the measurement point 8, although they are adjacent to each other as described above.

Regarding the intensity and direction of the curse light 9 ordered in the above state, if this is expressed in a vector diagram, the fifth
In the figure, the intersection angle θ is extremely small in the vector representation of the phase matching conditions of the General Curse optical system (not shown). Therefore, a spectroscope 15 is placed at a predetermined position in the generation direction of the cursed light 9 calculated according to the phase matching condition.
By placing and observing the cursed light 9, the cursed light 9 can be measured.

Next, a collinear Curse optical device was constructed using the Curse optical device of the above embodiment, a collinear Curse optical device in which the knives 11 and 12 of the Curse optical device were omitted, and an excitation light source, a Stokes light source, a condensing lens, etc. similar to these. The results of a comparative experiment using the boxcurse optical device will be explained with reference to FIG.

Carbon dioxide, which has a low concentration in the air, is ejected from a capillary at the measurement point, and the capillary is moved before and after the measurement point along the optical axis. The relationship between distance and relative intensity is as shown in FIG. 9 when the intensity of the cursed light is used as a reference.

In Figure 9, the horizontal axis is the distance from the focal point, 0
is the focus, the plus side is downstream from the focus, the minus side is upstream from the focus, and the vertical axis is the relative intensity of the curse light. Graph C shows experimental results using the collinear curse optical device. In other words, the intensity at the point L=0 is 1.0, and L=±
It is a curve in which all the curses near the car shine until around 3mm. Therefore, the area for detecting curse light is 6 m.
m, the spatial resolution is 5 mm. Graph B
shows experimental results using the boxcurse optical device. It can be seen that although the relative intensity has decreased to 1/7 compared to graph C, the spatial resolution has increased 12 times to about 0.5 mm. Therefore, it can be seen that the boxcurse optical device is suitable when the concentration of the object to be measured is high and the spatial resolution is a consideration, but it becomes impossible to detect when the concentration is low.

The graph shows experimental results based on the embodiment of the Curse optical device of the present invention. According to graph K, the spatial resolution is 2
mm, which is an improvement of about three times compared to the collinear curse optical device. The graph shows that the relative intensity at the point L=0 has been attenuated by only about 40% when compared with graph C for the collinear curse optical device, and that the signal strength has been improved when compared with graph B for the box curse optical device. I know that there is.

Although the embodiments of the curse optical device according to the present invention have been described in detail above, the present invention is not limited to the above embodiments, and without departing from the scope of the present invention described in the claims.
Various design changes are possible. For example, instead of using a dichroic mirror placed at the intersection of the excitation light optical path and the Stokes light optical path, which transmits the excitation light and reflects the Stokes light, it reflects the excitation light and produces the Stokes light. It is also possible to use something that transmits
It is also possible to check whether the passage areas of the excitation light and Stokes light on the surface of the dichroic mirror placed at the intersection of the excitation light and Stokes light are in contact by directly observing the dichroic mirror. be.

〔Effect of the invention〕

As described above, according to the present invention, a curse optical device compensates for the drawbacks of each of the collinear curse optical system and the box curse optical system, and also has the advantages of each, specifically, compared to the collinear curse optical system. The spatial resolution is high, and the signal strength is relatively strong, between the signal strength of a collinear curse optical system and that of a box curse optical system, and the optical axis adjustment is the simplest among the curse optical devices. A similarly simple curse optical device is obtained.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of an embodiment of a curse optical device according to the present invention, and FIGS. 2 to 4 are explanatory diagrams of a conventional curse optical system,
FIG. 2 shows a general curse optical system, FIG. 3 shows a collinear curse optical system, and FIG. 4 shows a box curse optical system. FIG. 5 is a vector representation diagram of the phase matching conditions of the general curse optical system, FIG. 6 is a vector representation diagram of the phase matching conditions of the collinear curse optical system, and FIG. 7 is a vector representation diagram of the phase matching conditions of the box curse optical system. A vector representation diagram of matching conditions. FIG. 8 is a view taken along the line A-A' in FIG. FIG. 4 is a comparative explanatory diagram of measurement results obtained by measuring curse light using the method. 1... Excitation light source, 2... Excitation light, 2a
...Reflected leakage light, 4...Stokes light source,
5...Stokes light, 5a...Transmitted leak light,
7... Condenser lens, 8... Measurement point (focal point)
, 9...curse light, lO... dichroic mirror,
11... Naifetsuji (excitation light shield), 12...
・Naifetsuji (Stokes light shield), 16...
Screen, Agent Patent Attorney Yusuke Hiraki 3: Half mirror 2: Excitation source viJ3 Figure (Collinear Curse Optical System) No. 11 (Box Curse Optical System) 4 2, 5 Upstream Focus Downstream Point

Claims (1)

[Scope of Claims] 1. An excitation light source that generates excitation light; a Stokes light source that generates Stokes light; and a source that is disposed at the intersection of the excitation light and Stokes light, and that emits either the excitation light or the Stokes light. a dichroic mirror that transmits one beam and reflects the other to make the transmitted one luminous flux and the reflected other luminous flux parallel; and a dichroic mirror disposed between the dichroic mirror and the measurement point, a condensing lens that narrows a luminous flux of excitation light and Stokes light via a colored mirror to a measurement point; in a Kerse optical device, the dichroic mirror of the excitation light is located between the excitation light source and the dichroic mirror; An excitation light shield is provided to adjust an area of incidence of the Stokes light to the dichroic mirror, and a Stokes light shield is provided between the Stokes light source and the dichroic mirror to adjust an area of incidence of the Stokes light to the dichroic mirror. A curse optical device characterized in that the two light beams made parallel by the dichroic mirror can be brought into close contact and adjacent to each other. 2. The excitation light shield and the Stokes light shield are both formed in a knife-edge shape, and their positions are adjusted by moving in a direction perpendicular to the traveling direction of the excitation light and Stokes light, respectively. A curse optical device according to claim 1, characterized in that: 3. The excitation light source is a Yag laser, an excimer laser, or a nitrogen laser, and the Stokes light source is a wavelength-tunable laser. Curse optical device described in. 4. An excitation light source that generates excitation light, a Stokes light source that generates Stokes light, and is disposed at the intersection of the excitation light and Stokes light, and transmits the excitation light and reflects the Stokes light to transmit the transmitted light. a dichroic mirror that parallelizes the luminous flux of the excitation light and the reflected Stokes light; and a dichroic mirror disposed between the dichroic mirror and the measurement point, the excitation light and the Stokes light passing through the dichroic mirror. a condensing lens that narrows down a luminous flux to a measurement point, and an excitation light beam between the excitation light source and the dichroic mirror that adjusts an incident area of the excitation light to the dichroic mirror. By providing a shielding device and a Stokes light shielding device between the Stokes light source and the dichroic mirror to adjust the incident area of the Stokes light to the dichroic mirror, the dichroic mirror allows the Stokes light to the two light beams are closely adjacent to each other, and furthermore, the reflected leakage light of the excitation light from the dichroic mirror and the transmitted leakage light of the Stokes light from the dichroic mirror are projected. A curse optical device characterized in that it is provided with a translucent screen.