JP2018125227A - Laser driving light source device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure that prevents fire (plasma) generated by pulsed laser light from disappearing by the pulsed laser light when the plasma is generated and maintained by the CW laser light in a laser driving light source device that converges a pulsed laser light and irradiates a plasma container in which a light emitting medium is sealed with the pulsed laser light to generate a preliminary discharge, and converges CW laser light and irradiates the plasma generated by the preliminary discharge with the CW laser light to generate and maintain plasma in the plasma container.SOLUTION: A converging point of a pulsed laser beam in a plasma container and a converging point of the CW laser beam are separated such that the pulsed laser beam does not strike the plasma at the converging point of the CW laser beam.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a laser-driven light source device, and more particularly, to a laser-driven light source device that generates plasma by condensing and irradiating pulse laser light and CW laser light in a plasma container.

2. Description of the Related Art In recent years, ultraviolet light sources with large input power have been used in the manufacturing process of objects to be processed such as semiconductors, liquid crystal substrates and color filters. What is used as an ultraviolet light source is a high-pressure discharge lamp of a type that generates an arc discharge between electrodes in a glass plasma container filled with mercury vapor or a rare gas.
In the manufacturing process described above, it is required to further shorten the processing time. Therefore, the high-pressure discharge lamp used for this purpose is required to further improve the radiance. In order to improve the radiance of the high-pressure discharge lamp, it is necessary to increase the input power.
However, when this type of high-pressure discharge lamp increases the input power, the electrodes in the glass plasma vessel are exposed to arc discharge and become extremely hot and gradually evaporate, or spattered by high-speed particles generated by the arc discharge. It was inevitable that the electrode was worn out. The metal constituting the electrode generated by evaporation or sputtering, generally tungsten, adheres to the inner wall surface of the glass plasma container, reduces the ultraviolet transmittance of the glass plasma container, and on the surface of the workpiece such as a semiconductor. There is a problem that the irradiance is lowered, the processing capacity is lowered, and the lamp life is shortened.

In order to solve such a problem of the high-pressure discharge lamp, JP 2009-532829 A (Patent Document 1) encloses a luminescent medium in a chamber (plasma container) and ionizes the luminescent medium by an ignition source. In addition, a light source that generates high-intensity light by irradiating the light emitting medium with a continuous wave (CW) laser and supplying substantially continuous energy has been proposed (claims 17 and 30).
The use of pulsed laser light as an ignition source for ionizing the luminescent medium is also disclosed (claims 20 and 43).
This light source generates a discharge in the chamber by an ignition source to ignite the luminescent medium, and then supplies or substantially continuously supplies the luminescent medium with a plasma that generates high brightness light. Thus, the temperature of the plasma rises until it is balanced by radiation and other processes and can be as high as 10,000K to 20000K. The short wavelength ultraviolet energy emitted from the high temperature plasma is extremely high.

However, in Patent Document 1, a specific configuration of a pulse laser as an ignition source for ionizing a light emitting medium and a continuous wave laser for supplying substantially continuous energy to the light emitting medium, In particular, the relationship between the focal point of the pulse laser and the focal point of the continuous wave laser is not particularly considered and is not shown. Therefore, it is considered that the configuration assumed from the description in consideration of other embodiments in the related art is as follows.
As shown in FIG. 8, in the laser drive light source device 50, a pulsed laser beam 53 focused in the chamber 52 is irradiated to a chamber (plasma container) 52 in which a light emitting medium is enclosed, and the pulsed laser beam 53 Similarly, a continuous laser beam (CW laser beam) 54 focused on the same point as the focal point of the pulsed laser beam 53 in the chamber 52 with respect to the plasma (fire type) 55 generated at the focal point. Is to irradiate.

  However, when the condensing point of the pulse laser used for the ignition source and the condensing point of the continuous wave laser that supplies energy to the light emitting medium coincide with each other, plasma generated once by the pulse laser is used. It turns out that there is a problem that disappears. The phenomenon that this plasma disappears will be described below with reference to FIGS. 9 and 10. FIG.

As shown in FIG. 9, the pulse laser beam 53 for ionizing the light emitting medium in the plasma container 52 and the continuous wave laser light (hereinafter referred to as CW laser light) 54 irradiated to the plasma 55 of the light emitting medium are as follows. Irradiated with overlapping.
That is, in the period t1, as shown in FIG. 10A, plasma (fire type) 55 of the light emitting medium is generated by preliminary discharge of the pulse laser beam 53, and the plasma 55 is irradiated with the CW laser beam 54. The plasma 55 is to be maintained and generated.
However, also in the subsequent period t 2, the plasma 55 that is generated by the preliminary discharge by the pulse laser beam 53 and is to be generated and maintained by the CW laser beam 54 is also exposed to the pulse laser beam 53.

As shown in FIG. 10B, the plasma 55 exposed to the pulsed laser beam 53 is rapidly heated and expanded by the pulsed laser beam 53, and the charged particles in the plasma 55 are scattered in all directions, so that the plasma is extinguished. Will be. Although the CW laser beam 54 continues to be applied to the space where the charged particles disappear, the state where the charged particles disappear is the same as the state without preliminary ionization, so that no plasma is generated.
That is, even if the plasma 55 generated by the preliminary discharge by the pulse laser beam 53 is maintained by the CW laser beam 54, the plasma 55 is extinguished by the pulse laser beam 53 irradiated at the same time.

  In this way, the pulse laser beam can cause a phenomenon like an explosion by rapidly heating and expanding the space near the condensing point, so that a preliminary discharge of the luminescent medium is formed in the plasma vessel. Is beneficial. However, on the other hand, if the condensing point of the CW laser coincides with the condensing point of the pulse laser, the plasma generated and maintained by the pulse laser and generated and maintained by the CW laser light is now the pulse laser. There is a contradictory problem of being extinguished by light.

It is considered that the above problem can be solved by shifting the irradiation time of the pulse laser light and the irradiation time of the CW laser light.
However, the plasma (fire type) generated by the preliminary discharge by the pulse laser beam has a very short life, and even if the CW laser beam is irradiated after stopping the pulse laser beam irradiation, the plasma (fire type) disappears at that time. In addition, the plasma cannot be maintained and generated, and it is absolutely necessary to irradiate the pulse laser beam and the CW laser beam simultaneously for a certain period.

Special table 2009-532829

  In view of the above-mentioned problems of the prior art, the present invention generates a preliminary discharge by condensing and irradiating a pulse laser beam from a pulse laser source in a plasma container in which a light emitting medium is sealed, and is generated by the preliminary discharge. In a laser-driven light source device that generates and maintains plasma in a plasma container by condensing and irradiating the plasma with CW laser light from a CW laser source, the plasma generated and maintained by the CW laser light is extinguished by pulsed laser light It is intended to provide a structure that does not.

In order to solve the above-described problems, in the laser-driven light source device according to the present invention, the pulse laser beam and the CW laser beam have different wavelengths and are incident on the same condenser lens. The condensing point of light and the condensing point of the CW laser light are separated and condensed in the plasma container.
In addition, the plasma container has a tube shape, and the condensing position of the CW laser light is located at a substantially central point of the plasma container, and a concave reflecting mirror is provided so as to surround the plasma container. The condensing point of the CW laser light is at the focal point of the concave reflecting mirror.
The plasma container includes a main body having a concave reflecting surface, an incident window provided in a rear opening of the main body, and an emission window provided in a front opening of the main body. The main body and the incident window A sealed space is formed by the exit window, and the condensing position of the CW laser light is at the focal point of the concave reflecting surface of the main body.

Also, a pulse laser source and a CW laser source are provided, and a dichroic mirror is disposed between these laser sources and the condenser lens, and the dichroic mirror transmits one of the pulse laser light and the CW laser light, It is characterized by reflecting the other.
A first dichroic mirror that is disposed between the pulse laser source and the CW laser source and the condenser lens and transmits one of the pulse laser light and the CW laser light and reflects the other; The pulse laser beam and the CW laser beam that are disposed in front of the plasma vessel on the excitation light emission side, pass through the condenser lens, are reflected toward the plasma vessel, and the excitation light from the plasma vessel is transmitted. And a second dichroic mirror.
And a fiber coupler having fibers corresponding to the pulse laser source and the CW laser source, respectively, and the combined fiber of the fiber coupler is opposed to the condenser lens with an achromatic lens interposed therebetween. Features.

According to the present invention, the wavelength of the pulse laser beam and that of the CW laser beam are set to be different from each other, and the condensing point of the pulse laser beam and the condensing point of the CW laser beam are set in the plasma container by using the chromatic aberration of the condenser lens. The plasma generated by the preliminary discharge of the pulsed laser beam can be moved to the condensing point of the CW laser beam by the CW laser beam, and remains at the condensing point. The plasma to be generated / maintained by the above is not extinguished by the pulse laser beam, and the plasma is stably maintained.
Further, since the pulse laser beam and the CW laser beam are incident on the same condenser lens, the overall structure is simplified.

In addition, since the plasma vessel has a tube shape and the condensing point of the CW laser beam is positioned at the substantially central point of the plasma vessel, high-temperature plasma continues at the center of the plasma vessel, so that the thermal The effect can be prevented.
In addition, the plasma container is composed of a main body having a concave reflecting surface, an incident window provided in the rear opening of the main body, and an emission window provided in the front opening of the main body. To provide a plasma container that can use ceramics or metal other than quartz glass for the window or exit window, and that does not cause ultraviolet distortion even when irradiated with high-power UV or VUV light from plasma. Can do.
In addition, since the focal point of the concave reflecting surface coincides with the condensing point of the CW laser light, the excitation light excited by the plasma maintained by the CW laser light is condensed light according to the shape of the concave reflecting surface. Alternatively, the light can be emitted from the plasma container to the outside as parallel light.

Explanatory drawing of the laser drive light source device which concerns on the 1st Example of this invention. Explanatory drawing of the behavior of the plasma of the laser drive light source device of this invention. Explanatory drawing of the 2nd Example of this invention. Explanatory drawing of the 3rd Example of this invention. Explanatory drawing of the 4th Example of this invention. Explanatory drawing of the 5th Example of this invention. Explanatory drawing of the 6th Example of this invention. Explanatory drawing of the laser drive light source device assumed from a prior art. Irradiation chart of pulse laser and CW laser. Explanatory drawing of the behavior of the plasma of the conventional laser drive light source device.

FIG. 1 shows a laser-driven light source device 1 according to a first embodiment of the present invention. An ionic light-emitting medium such as a rare gas or mercury is enclosed in a plasma container 2. The plasma vessel 2 can take various forms, but in this embodiment, it has a tube shape. Here, the tube shape means an arc tube shape such as a substantially spherical shape or a substantially elliptic rotating body shape in the lamp technology.
The laser-driven light source device 1 of the present invention includes a pulse laser source 3 and a CW laser source 4, and the pulse laser light 3L from the pulse laser source 3 and the CW laser light 4L from the CW laser source 4 are: The wavelengths are different from each other.
In this embodiment, description will be made on the assumption that the wavelength of the CW laser light 4L is longer than the wavelength of the pulsed laser light 3L. For example, when the wavelength of the CW laser beam 4L is 1064 ± 5 nm and the wavelength of the pulse laser beam 3L is 532 ± 5 nm, or the wavelength of the CW laser beam 4L is 1550 ± 5 nm and the wavelength of the pulse laser beam 3L is 523 In the case of 5 ± 5 nm.

The same condenser lens 5 is irradiated with the pulse laser light 3L from the pulse laser source 3 and the CW laser light 4L from the CW laser source 4. For this purpose, a dichroic mirror 6 is arranged between the palace laser source 3 and the CW laser source 4 and the condenser lens 5.
The dichroic mirror 6 reflects the pulse laser beam 3L and transmits the CW laser beam 4L.
Of course, the arrangement of the pulse laser source 3 and the CW laser source 4 can be reversed, and the dichroic mirror 6 can transmit the pulse laser beam 3L and reflect the CW laser beam 4L.

With such an arrangement, the pulse laser beam 3L from the pulse laser source 3 is reflected by the dichroic mirror 6 and is condensed by the condensing lens 5 on the condensing point 3a in the plasma container 2.
On the other hand, the CW laser light 4L from the CW laser source 4 passes through the dichroic mirror 6 and is condensed on the condensing point 4a in the plasma container 2 by the same condenser lens 5. The condensing point 4a of the CW laser light 4L is at a position separated from the condensing point 3a of the pulse laser light 3L.

Thus, the condensing point 3a of the pulsed laser light 3L condensed by the same condensing lens 5 and the condensing point 4a of the CW laser light 4L are in different positions due to the chromatic aberration of the condensing lens 5. It is.
By the condensing lens 5 having this chromatic aberration, the pulse laser light 3L and the CW laser light 4L are condensed at a condensing point corresponding to each wavelength. The material of the condenser lens 5 is, for example, BK-7, quartz, calcium fluoride, or the like.
In this embodiment, the condensing point 3a of the short-wavelength pulsed laser light 3L is behind the condensing point 4a of the long-wavelength CW laser light 4L on the optical axis of the CW laser light 4L (laser It is located on the front side of the light traveling direction.
At this time, it is desirable to arrange the condensing point 4a of the CW laser beam 4L so as to be located at a substantially central point of the plasma vessel 2.

A concave reflecting mirror 7 is provided so as to surround the plasma container 2, and the condensing point 4 a of the CW laser light 4 </ b> L is located at the focal point of the concave reflecting mirror 7.
Thereby, the excitation light EL generated by the plasma generated in the plasma container 2 is reflected by the concave reflecting mirror 7 and emitted from the front opening. At this time, whether the excitation light EL is extracted as parallel light or as condensed light is selected depending on the shape of the concave reflecting mirror 7. In this embodiment, the concave reflecting mirror 7 is configured as a parabolic mirror, and the excitation light EL is emitted as parallel light.

  In the above configuration, as shown in FIG. 2, when the pulse laser beam 3L is condensed and irradiated into the plasma container 2, a preliminary discharge is generated near the condensing point 3a in the plasma container 2, and the fire type 8 is Generated. In this state, when the CW laser light 4L is condensed and irradiated near the fire type 8, the fire type 8 moves to the condensing point 4a of the CW laser light 4L, and plasma is generated by the irradiation of the CW laser light 4L. 9 is generated. Thereafter, the irradiation of the pulse laser beam 3L is stopped, and the plasma 9 is maintained at the position of the condensing point 4a by continuously irradiating the CW laser beam 4.

3 is an example in which the plasma vessel 2 has a structure other than a tube shape.
The plasma container 2 has a cylindrical main body 20, and a concave reflecting surface 21 is formed on the inner surface thereof. The concave reflecting surface 21 is appropriately selected such as an elliptical shape or a parabolic shape. The main body 20 has a rear opening 20a and a front opening 20b, and a through hole 22 for passing a laser beam is formed at the center. An entrance window 23 is provided corresponding to the rear opening 20a, and an exit window 24 is provided corresponding to the front opening 20b.
The incident window 23 corresponding to the rear opening 20 a of the main body 20 is attached to a metal window frame member 25, and the window frame member 25 is attached to the main body 20 by a metal cylinder 26. Similarly, the emission window 24 corresponding to the front opening 20 b is attached to a metal window frame member 27, and this window frame member 27 is attached to the main body 20 by a metal cylinder 28.
A sealed space S is formed by the main body 20 having the concave reflecting surface 21, the entrance window 23, and the exit window 24, and a light emitting element is enclosed in the sealed space S, so that the plasma container 2 is configured. ing.

The CW laser beam 4L passes through the dichroic mirror 6 and enters the plasma container 2 through the incident window 23 while being condensed by the condensing lens 5 with respect to the plasma container 2 having such a configuration. To collect light.
On the other hand, the pulse laser beam 3L is reflected by the dichroic mirror 6 to change the optical path, is condensed by the same condenser lens 5, is incident into the plasma container 2 from the incident window 23, and is condensed in the plasma container 2. .
As described above, the pulse laser beam 3L and the CW laser beam 4L pass through the dichroic mirror 6 and are condensed in the plasma container 2 by the same condenser lens 5, but based on the chromatic aberration of the condenser lens 5. The light condensing point 3a and the light condensing point 4a are separated from each other.
In this embodiment, the condensing point 3a of the pulsed laser light 3L is separated from the condensing point 4a of the CW laser light 4L on the optical axis to the rear side (the front side in the laser light traveling direction).
In this case, the condensing point 4 a of the CW laser beam 4 coincides with the focal point of the concave reflecting surface 21 of the plasma container 2.

  The excitation light EL excited by the plasma generated and maintained by the CW laser light 4L in the plasma container 2 is reflected by the concave reflecting surface 21 and emitted to the outside through the emission window 24.

  According to the second embodiment, ceramics or metal other than quartz glass can be used for the main body 20, the entrance window 23, and the exit window 24 that constitute the plasma container 2, and UV light or VUV light is excited. Even in this case, it is possible to provide a plasma container in which ultraviolet distortion does not occur even when irradiated with high-power UV light or VUV light from plasma.

In the third embodiment shown in FIG. 4, both the pulse laser beam and the CW laser beam are incident on the plasma container from the front opening side of the concave reflecting mirror.
A first dichroic mirror 10 is disposed between the pulse laser source 3 and the CW laser source 4 and the condenser lens 5, and the first dichroic mirror 10 reflects the pulse laser light 3L, It transmits the CW laser beam 4L.
Of course, the arrangement of the pulse laser source 3 and the CW laser source 4 can be reversed, and the first dichroic mirror 10 can transmit the pulse laser beam 3L and reflect the CW laser beam 4L. The first embodiment is the same as the first embodiment.

A second dichroic mirror 11 is disposed in front of the concave reflecting mirror 7 surrounding the plasma container 2, that is, in front of the excitation light emission side. The second dichroic mirror 11 includes the pulse laser beams 3L and CW. The laser beam 4L is reflected and the excitation light EL from the plasma container 2 is transmitted.
With this configuration, both the pulse laser beam 3L from the pulse laser source 3 and the CW laser beam 4L from the CW laser source 4 pass through the same condenser lens 5 and reach the second dichroic mirror 11, where they are reflected. To the plasma vessel 2.
Then, although the light is condensed in the plasma container 2, the respective condensing points 3a and 4a are separated at different positions according to the wavelength. That is, the condensing point 3a of the pulsed laser light 3L is located on the front side of the traveling direction of the laser light on the optical axis with respect to the condensing point 4a of the CW laser light 4L.

  Also in this embodiment, the condensing point 4a of the CW laser light 4L is located at the focal point of the concave reflecting mirror 7. Thereby, the excitation light EL based on the plasma generated in the plasma container 2 is reflected by the concave reflecting mirror 7 and emitted from the front opening. This excitation light EL passes through the second dichroic mirror 11 and is emitted to the outside.

The fourth embodiment shown in FIG. 5 differs from the third embodiment in FIG. 4 in the shape of the plasma container 2.
That is, the cylindrical main body 30 constituting the plasma container 2 has a concave reflecting surface 31 formed on the front surface side, and a front window 32 is provided at the front opening thereof. A sealed space is formed, and a light emitting element is enclosed therein.
Other configurations are the same as those of the third embodiment shown in FIG.

The pulse laser beam 3L and the CW laser beam 4L are respectively supplied to the plasma container through the pulse laser source 3 (CW laser source 4) → the first dichroic mirror 10 → the condensing lens 5 → the second dichroic mirror 11 → the front window 32. 2 to collect light. At this time, the condensing point 3a of the pulsed laser light 3L and the condensing point 4a of the CW laser light 4L are separated according to the respective wavelengths. In the fourth embodiment, the condensing point 3a of the pulsed laser light 3L As in the third embodiment, the condensing point 3a is positioned on the front side in the advancing direction of the laser light with respect to the condensing point 4a of the CW laser light 4L on the optical axis of the laser light.
Then, the excitation light EL generated in the plasma container 2 is emitted from the front window 32, passes through the second dichroic mirror 11, and is emitted to the outside.

In the fifth embodiment shown in FIG. 6, a fiber coupler 40 is used as a means for guiding the pulse laser beam 3L and the CW laser beam 4L to the same condenser lens 5.
Here, the fiber coupler is an optical component having a function of combining or branching light having the same wavelength, or combining or demultiplexing light having different wavelengths. In the present invention, laser light having different wavelengths is used. Used to multiplex.
The pulse laser beam 3L from the pulse laser source 3 and the CW laser beam 4L from the CW laser source 4 are incident on one end of each of the fibers 41 and 42 of the fiber coupler 40, and the laser beams having different wavelengths are multiplexed. Then, the combined laser light emitted from the combining fiber 43 is incident on the condenser lens 5 through the achromatic lens (achromatic lens) 45.

  Here, the achromatic lens 45 is a lens in which different optical characteristics are bonded and bonded together, and is used for correcting chromatic aberration. In the present invention, using this property, the light emitted from the multiplexing fiber 43 of the fiber coupler 40 is converted into parallel light and then incident on the condenser lens 5. By using the achromatic lens 45, it becomes possible to make the laser light incident on the condensing lens 5 as parallel light, and it becomes easy to align the condensing point of the laser light.

In the first to fifth embodiments described above, the example in which the wavelength of the CW laser beam is longer than the wavelength of the pulse laser beam has been described. However, in the sixth embodiment of FIG. This is an example in which the wavelength is shorter than the wavelength of the pulse laser beam.
In this case, the condensing point 3a of the pulse laser light 3L and the condensing point 4a of the CW laser light 4L are the same at different positions, but the condensing point 3a of the pulse laser light 3L is the light On the axis, the CW laser beam 4L is separated from the condensing point 4a on the front side (the front side in the traveling direction of the laser beam).
At this time, the condensing point 4a of the CW laser light 4L is positioned at the focal point of the concave reflecting surface 21 of the plasma vessel 2 as in the other embodiments.

Hereinafter, the separation distance of the condensing point due to the difference in wavelength between the pulse laser beam and the CW laser beam was evaluated.
(1) CW laser beam wavelength: 1064 ± 5nm
Pulse laser beam wavelength: 532 ± 5nm
Condenser lens: LA1472 manufactured by Thorlabs (BK-7, F@587.6nm=20mm, R = 10.3 + 0.0-0.1mm)

Focal length of plano-convex lens F = R / (n−1)
R: radius of curvature of the lens
n (λ): Refractive index

Focal length of CW laser beam (1064 ± 5nm) F1 = 20.328 ~ 20.333mm
Pulse laser beam (532 ± 5nm) focal length F2 = 19.817 ~ 19.838mm)

The difference (F1−F2) between the two is the separation distance ΔF between the condensing points of the CW laser beam and the pulse laser beam.
Separation distance ΔF = 0.49 ~ 0.52mm

(2) CW laser beam wavelength: 1550 ± 5nm
Pulse laser beam wavelength: 523.5 ± 5nm
Condenser lens: LA1255 manufactured by Thorlabs (BK-7, F@587.6nm=50mm, R = 25.8 + 0.0-0.1mm)

Focal length of CW laser beam (1550 ± 5nm) F1 = 51.526 ~ 51.539mm
Pulse laser beam (523.5 ± 5nm) focal length F2 = 49.592 ~ 49.647mm)

Separation distance ΔF = 1.88 ～ 1.95mm

  As described above, in the present invention, pulse laser light and CW laser light having different wavelengths are incident on the same condensing lens, and the chromatic aberration of the condensing lens is used, so that the pulse in the plasma container can be obtained. Since the condensing point of the laser beam and the condensing point of the CW laser beam are separated from each other, the kind of plasma generated due to the preliminary discharge generated near the condensing point of the pulse laser beam becomes the condensing point of the CW laser beam Since the plasma is generated by moving, the pulsed laser beam does not hit the plasma, and the generated plasma is not extinguished by the pulsed laser beam, so that the plasma can be generated and maintained stably. it can.

DESCRIPTION OF SYMBOLS 1 Laser drive light source device 2 Plasma container 20 Main body 20a Back opening 20b Front opening 21 Concave reflective surface 22 Through-hole 23 Entrance window 24 Exit window 25 (For entrance window) Window frame member 26 Metal cylinder 27 (For exit window) Window frame Member 28 Metal cylinder 3 Pulse laser source 3L Pulse laser light 3a Condensing point of pulse laser light 4 CW laser source 4L CW laser light 4a Condensing point of CW laser light 5 Condensing lens 6 Dichroic mirror 7 Concave mirror 8 Fire type DESCRIPTION OF SYMBOLS 9 Plasma 10 1st dichroic mirror 11 2nd dichroic mirror 30 Main body 31 Concave-reflection surface 32 Front window 40 Fiber coupler 41, 42 Fiber 43 Combined fiber 45 Achromatic lens EL Excitation light

Claims (6)

A preliminary discharge is generated by condensing and irradiating a pulsed laser beam from a pulsed laser source into a plasma vessel in which a light emitting medium is sealed, and the CW laser beam from the CW laser source is condensed on the plasma generated by the preliminary discharge. In a laser-driven light source device that generates and maintains plasma in a plasma container by irradiation,
The pulse laser beam and the CW laser beam have different wavelengths, and are incident on the same condenser lens,
The condensing point of the pulsed laser light and the condensing point of the CW laser light are separately collected in the plasma container,
A laser-driven light source device characterized by that. The plasma vessel has a tube shape, and a condensing point of the CW laser light is located at a substantially central point of the plasma vessel,
A concave reflecting mirror is provided so as to surround the plasma container, and the condensing point of the CW laser light is at the focal point of the concave reflecting mirror.
The laser-driven light source device according to claim 1. The plasma container includes a main body having a concave reflecting surface, an incident window provided in a rear opening of the main body, and an emission window provided in a front opening of the main body, the main body, the incident window, and the emission A sealed space is formed by the window,
The condensing point of the CW laser light is at the focal point of the concave reflecting surface of the main body,
The laser-driven light source device according to claim 1. A dichroic mirror is disposed between the pulse laser source and the CW laser source and the condenser lens,
The dichroic mirror transmits one of pulsed laser light and CW laser light and reflects the other.
The laser-driven light source device according to any one of claims 1 to 3. A first dichroic mirror that is disposed between the pulse laser source and the CW laser source and the condenser lens and transmits one of the pulse laser light and the CW laser light and reflects the other;
The pulse laser beam and the CW laser beam, which are arranged in front of the excitation light emission side of the plasma container and pass through the condenser lens, are reflected toward the plasma container and transmit the excitation light from the plasma container. A second dichroic mirror,
The laser-driven light source device according to claim 1, comprising: A fiber coupler having fibers respectively corresponding to the pulse laser source and the CW laser source;
The multiplexing fiber of the fiber coupler is opposed to the condenser lens with an achromatic lens interposed therebetween.
The laser-driven light source device according to any one of claims 1 to 3.

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