WO2017203791A1 - Laser-driven light source device - Google Patents

Laser-driven light source device Download PDF

Info

Publication number
WO2017203791A1
WO2017203791A1 PCT/JP2017/008457 JP2017008457W WO2017203791A1 WO 2017203791 A1 WO2017203791 A1 WO 2017203791A1 JP 2017008457 W JP2017008457 W JP 2017008457W WO 2017203791 A1 WO2017203791 A1 WO 2017203791A1
Authority
WO
WIPO (PCT)
Prior art keywords
laser
light
plasma
laser beam
laser light
Prior art date
Application number
PCT/JP2017/008457
Other languages
French (fr)
Japanese (ja)
Inventor
住友　卓
利夫 横田
北川　鉄也
祐 山埼
Original Assignee
ウシオ電機株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP2016103203A external-priority patent/JP2017212061A/en
Priority claimed from JP2017018220A external-priority patent/JP2018125227A/en
Application filed by ウシオ電機株式会社 filed Critical ウシオ電機株式会社
Publication of WO2017203791A1 publication Critical patent/WO2017203791A1/en

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J65/00—Lamps without any electrode inside the vessel; Lamps with at least one main electrode outside the vessel
    • H01J65/04—Lamps in which a gas filling is excited to luminesce by an external electromagnetic field or by external corpuscular radiation, e.g. for indicating plasma display panels
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J61/00—Gas-discharge or vapour-discharge lamps
    • H01J61/02—Details
    • H01J61/025—Associated optical elements
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J61/00—Gas-discharge or vapour-discharge lamps
    • H01J61/02—Details
    • H01J61/12—Selection of substances for gas fillings; Specified operating pressure or temperature
    • H01J61/16—Selection of substances for gas fillings; Specified operating pressure or temperature having helium, argon, neon, krypton, or xenon as the principle constituent
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J61/00—Gas-discharge or vapour-discharge lamps
    • H01J61/02—Details
    • H01J61/12—Selection of substances for gas fillings; Specified operating pressure or temperature
    • H01J61/18—Selection of substances for gas fillings; Specified operating pressure or temperature having a metallic vapour as the principal constituent
    • H01J61/20—Selection of substances for gas fillings; Specified operating pressure or temperature having a metallic vapour as the principal constituent mercury vapour

Definitions

  • 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.
  • 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.
  • the high-pressure discharge lamp used for this purpose is required to further improve the radiance.
  • 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.
  • Patent Document 1 encloses an ionic medium in a chamber (plasma container) and uses the ionic medium as an ignition source.
  • a light source has been proposed that generates high-intensity light by applying a continuous wave (CW) laser to the ionized medium and supplying a substantially continuous energy. ).
  • CW continuous wave
  • the use of pulsed laser light as an ignition source for ionizing an ionic medium is also disclosed (claims 20 and 43).
  • This light source generates a discharge in a chamber by an ignition source to ignite an ionic medium, and then supplies or substantially continuously supplies energy to the ionized medium to maintain or generate a plasma that generates high intensity light
  • 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.
  • Patent Document 1 a specific configuration of a pulse laser as an ignition source for ionizing an ionic medium and a continuous wave laser for supplying substantially continuous energy to the ionized medium
  • the relationship between the focal position of the pulse laser and the focal position of the continuous wave laser is not particularly considered and is not illustrated. Therefore, it is considered that the configuration assumed from the description in consideration of other embodiments in the related art is as follows.
  • a pulse laser beam 53 condensed in the chamber 52 is irradiated to a chamber (plasma container) 52 in which an ionic medium is enclosed, and the pulse laser beam is irradiated.
  • a continuous laser beam (CW laser beam) 54 focused on the same point as the focusing point of the pulsed laser beam 53 in the chamber 52 is applied to the plasma (fire type) 55 generated at the focal point 53. Irradiation.
  • CW laser beam continuous laser beam
  • a pulsed laser beam 53 for ionizing an ionic medium in the plasma container 52, and a continuous wave laser beam (hereinafter referred to as CW laser beam) 54 irradiated to the plasma 55 of the ionized medium are superimposed and irradiated. That is, in the period t1, as shown in FIG. 18A, the plasma (fire type) 55 of the ionized medium is generated by the 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.
  • CW laser beam continuous wave laser beam
  • 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 to extinguish the plasma. Will be.
  • 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.
  • pulsed laser light 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 ionic medium is formed in the plasma vessel. Is useful.
  • the condensing point position of the CW laser and the condensing point position of the pulse laser coincide with each other, the plasma generated and maintained by the pulse laser and generated and maintained by the CW laser light is There is a contradictory problem that it is extinguished by pulsed laser light.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • the laser-driven light source device is characterized in that the focal position of the pulse laser beam and the condensing point position of the CW laser beam in the plasma container are separated from each other. Further, the plasma container is in a tube shape, and a condensing point position of the CW laser light is located at a substantially central point of the plasma container.
  • 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 point position of the CW laser light is at the focal position of the concave reflecting surface of the main body. Further, the condensing point position of the pulse laser beam is located on the optical axis of the CW laser beam.
  • the pulse laser beam and the CW laser beam have different wavelengths, are incident on the same condenser lens, and the focal point of the pulse laser beam and the focal point of the CW laser beam are It is characterized in that the light is collected separately in the plasma container.
  • the plasma container has a tube shape, and the condensing point 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.
  • a dichroic mirror is disposed between the pulse laser source and the CW laser source and the condenser lens, and the dichroic mirror transmits one of the pulse laser light and the CW laser light and reflects the other. It is characterized by being.
  • 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.
  • a second dichroic mirror 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 made to face the condenser lens with an achromatic lens interposed therebetween. It is characterized by.
  • the plasma generated by the preliminary discharge of the pulse laser beam is moved by the CW laser beam to the condensing point position of the CW laser beam at a position separated from the condensing point position of the pulse laser beam.
  • the plasma that is to be generated and maintained by the CW laser beam is not extinguished by the pulse laser beam, and the plasma is stably maintained. is there.
  • the plasma vessel has a tube shape and the condensing point position of the CW laser light is located at the substantially central point of the plasma vessel, the high temperature plasma continues at the center of the plasma vessel, and thus the biased heat to the tube wall Can be prevented.
  • 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.
  • the condensing point position of the CW laser light is at the focal position of the concave reflecting surface of the main body, the excitation light generated from the plasma maintained by the CW laser light is converted into the plasma container as the condensed light or parallel light. Can be emitted to the outside.
  • the focal point position of the pulse laser beam is positioned on the optical axis of the CW laser beam, the plasma generated by the pulse laser beam can easily shift to the focal point position of the CW laser beam.
  • the opening for laser beam incidence provided in the plasma vessel main body can be made into one place. Since the area of the concave reflecting surface can be expanded as compared with the case where the incident openings for the laser beam and the pulse laser beam are respectively provided, the amount of excitation light emitted to the outside can be increased.
  • the condensing point of the pulse laser light and the condensing point of the CW laser light in the plasma container by using the chromatic aberration of the condensing lens, assuming that the wavelengths of the pulse laser light and CW laser light are different. it can. Since the pulse laser beam and the CW laser beam are incident on the same condenser lens, the entire structure is simplified.
  • 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.
  • 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 plasma container 2 is irradiated with a pulse laser beam 3L from a pulse laser source (not shown) so as to be focused on a condensing point 3a in the plasma container 2.
  • CW laser light 4L is condensed and irradiated into the plasma container 2 from a CW laser source (not shown), and the condensing point 4a of the CW laser light 4L is the condensing point of the pulse laser light 3L. It is in a position separated from 3a.
  • the condensing point 3a of the pulse laser beam 3L is ahead of the condensing point 4a of the CW laser beam 4L on the optical axis X of the CW laser beam 4L (the progress of the CW laser beam).
  • the condensing point 4a of the CW laser light 4L is located substantially at the center point of the plasma vessel 2.
  • FIG. 2 shows another embodiment.
  • the condensing point 3a of the pulsed laser light 3L is located on the rear side (CW laser light) on the optical axis X with respect to the condensing point 4a of the CW laser light 4L.
  • the other configuration is the same as that of the embodiment of FIG. 1 described above.
  • FIG. 3 shows another embodiment.
  • the condensing point 3a of the pulse laser beam 3L is not on the optical axis X of the CW laser beam 4L, and is separated from the optical axis X by a predetermined distance. In the position.
  • FIGS. 5 to 9 show embodiments in which the plasma container 2 has a structure other than a tube shape.
  • the pulse laser beam and the CW laser beam are condensed on the same optical axis.
  • FIG. 5 is a cross-sectional view of the fourth embodiment.
  • the plasma vessel 2 has a cylindrical main body 10 with a concave reflecting surface 11 formed on the inner surface thereof.
  • the concave reflecting surface 11 is appropriately selected such as an elliptical shape or a parabolic shape.
  • the main body 10 is formed with a rear opening 10a and a front opening 10b.
  • An entrance window 12 is provided corresponding to the rear opening 10a
  • an exit window 13 is provided corresponding to the front opening 10b.
  • the incident window 12 corresponding to the rear opening 10 a of the main body 10 is attached to a metal window frame member 14, and the window frame member 14 is attached to the main body 10 by a metal cylinder 15.
  • a sealed space is formed by the main body 10 having the concave reflecting surface 11, the entrance window 12, and the exit window 13, and a light emitting element is enclosed in the sealed space, thereby forming the plasma container 2. .
  • the pulse laser beam 3L and the CW laser beam 4L are both condensed in the plasma vessel 2 with respect to the plasma vessel 2 having the above-described configuration, but the condensing point 3a and the condensing point 4a are located apart from each other. .
  • the condensing point 4a of the CW laser beam 4L coincides with the focal point F position of the concave reflecting surface 11 of the plasma container 2.
  • the condensing point 3a of the pulsed laser light 3L is separated from the condensing point 4a on the optical axis X of the CW laser light 4L to the front side (front side in the traveling direction of the CW laser light). ing.
  • a dichroic mirror 35 is arranged in the optical path of the CW laser beam 4L.
  • the dichroic mirror 35 transmits the CW laser beam 4L and reflects the pulse laser beam 3L.
  • the CW laser beam 4 ⁇ / b> L is collected by the condenser lens 17, passes through the dichroic mirror 35, enters from the incident window 12 of the plasma container 2, and is collected at the focal point F position of the concave reflecting surface 11. That is, the condensing point 4a of the CW laser beam 4L coincides with the focal point F of the concave reflecting surface 11.
  • the pulse laser beam 3L is irradiated from the lower side of FIG. 5 to the dichroic mirror 35 while being condensed by the condenser lens 18, and is reflected thereby to change the optical path from the incident window 12 into the plasma container 2. Is incident on.
  • the condensing point 3a of the pulse laser beam 3L is separated on the front side (near side) of the focal point 4a on the optical axis X of the CW laser beam 4L.
  • 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 11 and emitted to the outside through the emission window 13.
  • FIG. 7 shows still another fifth embodiment.
  • the CW laser light is incident from the rear of the plasma container, and the pulsed laser light is incident from the front. That is, the CW laser light 4L is incident through the incident window 12 of the plasma container 2, and the condensing point 4a of the CW laser light 4L is disposed so as to coincide with the focal point F position of the concave reflecting surface 11.
  • the CW laser beam 4L is condensed at the focal point F position of the concave reflecting surface 11.
  • a dichroic mirror 35 is disposed in front of the plasma container 2 (on the emission side). The dichroic mirror 35 reflects the pulse laser light 3L and transmits the excitation light EL from the plasma container 2. is there.
  • the pulse laser light 3L is irradiated from the upper side of FIG. 7 while being condensed by the condenser lens 18 and is reflected by the dichroic mirror 35 to change the optical path.
  • the light enters from the exit window 13 and is condensed inside.
  • the condensing point 3a of the pulsed laser light 3L is on the rear side (CW laser light) with respect to the condensing point 4a of the CW laser light 4L (focal point F of the concave reflecting surface 11) on the optical axis X of the CW laser light 4L. It is separated from the other side of the direction of travel.
  • the excitation light EL excited by the plasma generated and maintained by the CW laser light 4L is reflected by the concave reflecting surface 11 and emitted through the emission window 13, and is transmitted through the dichroic mirror 35 and emitted to the outside.
  • FIG. 8 and FIG. 9 show an example in which the CW laser light 4L is incident from the front of the plasma container 2 and the pulsed laser light 3L is incident from the rear as yet another embodiment.
  • a dichroic mirror 35 that reflects the CW laser light 4L and transmits the excitation light EL is disposed in front of the plasma container 2.
  • the pulse laser beam 3L is incident from the incident window 12 of the plasma container 2 and is condensed at the condensing point 3a. This condensing point 3 a is at a position different from the focal point F of the concave reflecting surface 11 of the plasma container 2.
  • the CW laser beam 4L is irradiated on the dichroic mirror 35 while being collected by the condenser lens 17, reflected there, and enters the plasma vessel 2 from the emission window 13 of the plasma vessel 2 by changing the optical path.
  • the condensing point 4a of the CW laser light 4L is arranged so as to coincide with the focal point F position of the concave reflecting surface 11, and the CW laser light 4L is condensed at the focal point F position of the concave reflecting surface 11. .
  • the excitation light EL excited by the plasma generated and maintained by the CW laser light 4L is reflected by the concave reflecting surface 11 and emitted through the emission window 13, and is transmitted through the dichroic mirror 35 and emitted to the outside.
  • the CW laser light 4L is incident on the plasma vessel 2 while being condensed, whereas in the seventh embodiment of FIG. 9, the CW laser light 4L is condensed. It is an example which injects into the plasma container 2 as parallel light, without being carried out.
  • the CW laser light 4L reflected by the dichroic mirror 35 and incident on the plasma container 2 as parallel light is reflected by the concave reflecting surface 11 and condensed at the focal point F. That is, also in this case, the condensing point 4a of the CW laser light 4L and the focal point F of the concave reflecting surface 11 are coincident.
  • the chromatic aberration of the condensing lens is used as means for separating the condensing point of the pulse laser beam and the condensing point of the CW laser beam.
  • the laser drive light source device 1 of the eighth embodiment of the present invention shown in FIG. 10 includes a pulse laser source 3 and a CW laser source 4, and the pulse laser light 3L from these pulse laser sources 3
  • the CW laser beams 4L from the CW laser source 4 have different wavelengths. 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.
  • 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.
  • a dichroic mirror 6 is disposed 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.
  • 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.
  • the pulse laser beam 3L from the pulse laser source 3 is reflected by the dichroic mirror 6 and is condensed by the condenser lens 5 on the condensing point 3a in the tube-shaped plasma container 2.
  • 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.
  • 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.
  • 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.
  • the condensing point 3a of the short-wavelength pulsed laser light 3L is located behind the condensing point 4a of the long-wavelength CW laser light 4L on the optical axis of the CW laser light 4L ( It is located on the front side of the traveling direction of the laser beam. 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 9 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 9.
  • the excitation light EL generated by the plasma generated in the plasma container 2 is reflected by the concave reflecting mirror 9 and emitted from the front opening.
  • whether to extract the excitation light EL as parallel light or as condensed light is selected depending on the shape of the concave reflecting mirror 9.
  • the concave reflecting mirror 9 is configured as a parabolic mirror, and the excitation light EL is emitted as parallel light.
  • the ninth embodiment of FIG. 11 is an example in which the plasma container 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.
  • 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.
  • 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.
  • 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.
  • 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).
  • 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.
  • ceramics or metal other than quartz glass can be used for the main body 20, the entrance window 23, and the exit window 24 constituting 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.
  • the tenth embodiment shown in FIG. 12 is an example in which both pulsed laser light and CW laser light are incident on the plasma container from the front opening side of the concave reflecting mirror.
  • a first dichroic mirror 36 is disposed between the pulse laser source 3 and the CW laser source 4 and the condenser lens 5, and the first dichroic mirror 36 reflects the pulse laser light 3L, It transmits the CW laser beam 4L.
  • the arrangement of the pulse laser source 3 and the CW laser source 4 can be reversed, and the first dichroic mirror 36 can transmit the pulse laser beam 3L and reflect the CW laser beam 4L. This is the same as the tenth eighth embodiment.
  • a second dichroic mirror 37 is disposed in front of the concave reflecting mirror 9 surrounding the plasma container 2, that is, in front of the excitation light emission side.
  • the laser beam 4L is reflected and the excitation light EL from the plasma container 2 is transmitted.
  • 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 37, where they are reflected.
  • the light is condensed in the plasma container 2, but 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.
  • the condensing point 4a of the CW laser light 4L is located at the focal point of the concave reflecting mirror 9.
  • the excitation light EL based on the plasma generated in the plasma container 2 is reflected by the concave reflecting mirror 9 and emitted from the front opening.
  • This excitation light EL passes through the second dichroic mirror 37 and is emitted to the outside.
  • the eleventh embodiment shown in FIG. 13 differs from the tenth embodiment of FIG. 12 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 tenth embodiment of 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 36 ⁇ the condensing lens 5 ⁇ the second dichroic mirror 37 ⁇ the front window 32. 2 to collect light.
  • the condensing point 3a of the pulse laser light 3L and the condensing point 4a of the CW laser light 4L are separated according to the respective wavelengths.
  • the condensing point 3a of the pulse laser light 3L As in the tenth embodiment, the condensing point 3a is positioned on the near side in the traveling 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 37, and is emitted to the outside.
  • a fiber coupler 40 is used as means for guiding the pulse laser beam 3L and the CW laser beam 4L to the same condenser lens 5.
  • 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.
  • 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.
  • the combined laser light emitted from the combining fiber 43 is incident on the condenser lens 5 through the achromatic lens (achromatic lens) 45.
  • the achromatic lens 45 is a lens in which different optical characteristics are bonded and bonded together, and is used for correcting chromatic aberration.
  • 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.
  • 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.
  • the example in which the wavelength of the CW laser beam is longer than the wavelength of the pulse laser beam has been described.
  • 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).
  • 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.
  • the condensing point position of the pulse laser light in the plasma container and the condensing point position of the CW laser light are separated from each other, they are generated near the condensing point of the pulse laser light. Since the plasma fire associated with preionization moves to the condensing point of the CW laser beam and generates plasma, the pulsed laser beam does not hit this plasma, and the generated plasma is extinguished by the pulsed laser beam. The plasma can be generated and maintained stably without being generated.
  • the entire structure is simplified by making pulse laser light and CW laser light having different wavelengths incident on the same condensing lens and utilizing the chromatic aberration of the condensing lens.

Abstract

In this laser-driven light source device (1) a pulsed laser light (3L) is condensed and irradiated into a plasma container (2) having a light-emitting medium enclosed therein to generate a pre-discharge, and a CW laser light (4L) is condensed and irradiated onto the plasma generated by the pre-discharge, thereby generating and maintaining the plasma inside the plasma container (2). The laser-driven light source device (1) is provided with a structure wherein, when the plasma (spark) generated by the pulsed laser light (3L) is generated/maintained by the CW laser light (4L), the spark is not extinguished by the pulsed laser light (3L). The laser-driven light source device is characterized in that, inside the plasma container (2), a light-condensing point (3a) position for the pulsed laser light (3L) and a light-condensing point (4a) position for the CW laser light (4L) are separated in such a manner that the pulsed laser light (3L) does not hit the plasma present at the light-condensing point (4a) position for the CW laser light (4L).

Description

レーザ駆動光源装置Laser drive light source device
　この発明は、レーザ駆動光源装置に関するものであり、特に、プラズマ容器内にパルスレーザ光とＣＷレーザ光を集光照射してプラズマを生成するレーザ駆動光源装置に係わるものである。 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.
　近年、半導体、液晶基板およびカラーフィルタ等の被処理物の製造工程においては、入力電力の大きな紫外線光源を使用されている。紫外線光源として用いられているのは、水銀蒸気或いは希ガスを封入したガラスプラズマ容器内で電極間にアーク放電を発生させるタイプの高圧放電ランプである。
　上記製造工程においては、処理時間の一層の短縮化が要求されており、そのため、この用途に使用される高圧放電ランプには、より一層の放射輝度の向上が必要とされている。高圧放電ランプの放射輝度を向上させるためには、入力電力を増やすことが必要である。
　しかし、この種の高圧放電ランプは、入力電力を増やすと、ガラスプラズマ容器内の電極がアーク放電に曝されて極めて高温になって徐々に蒸発したり、また、アーク放電によって生じる高速粒子でスパッタされたりして、電極が消耗することが避けられなかった。これら蒸発ないしスパッタで生じた電極を構成する金属、一般的にはタングステンはガラスプラズマ容器の内壁面に付着し、ガラスプラズマ容器の紫外線の透過率を低下させ、半導体等の被処理物の表面における放射照度を低下させてしまい、処理能力の低下を招き、ランプ寿命が短くなるという問題がある。 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.
　このような高圧放電ランプの問題を解決するために、特表２００９－５３２８２９号公報（特許文献１）には、チャンバ（プラズマ容器）内にイオン性媒体を封入し、該イオン性媒体を点火源によってイオン化し、該イオン化媒体に対して連続波（ＣＷ）レーザを照射して、実質的に連続したエネルギーを供給することにより高輝度光を生成する光源が提案されている（請求項１７、３０）。
　そして、イオン性媒体をイオン化するための点火源として、パルスレーザ光を用いることも開示されている（請求項２０、４３）。
　この光源は、点火源によってチャンバ内で放電を発生させてイオン性媒体に点火し、次いで、イオン化媒体に実質的に連続したエネルギーを供給して高輝度光を発生するプラズマを維持または生成するものであって、プラズマの温度は、放射および他のプロセスによってバランスされるまで上昇し、１００００Ｋ～２００００Ｋという極めて高温になる。高温のプラズマから放射される短波長の紫外線エネルギーは極めて高いものである。 In order to solve such a problem of the high-pressure discharge lamp, Japanese Patent Application Publication No. 2009-532829 (Patent Document 1) encloses an ionic medium in a chamber (plasma container) and uses the ionic medium as an ignition source. A light source has been proposed that generates high-intensity light by applying a continuous wave (CW) laser to the ionized medium and supplying a substantially continuous energy. ).
The use of pulsed laser light as an ignition source for ionizing an ionic medium is also disclosed (claims 20 and 43).
This light source generates a discharge in a chamber by an ignition source to ignite an ionic medium, and then supplies or substantially continuously supplies energy to the ionized medium to maintain or generate a plasma that generates high intensity light However, 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.
　しかしながら、該特許文献１においては、イオン性媒体をイオン化するための点火源としてのパルスレーザと、イオン化媒体に対して実質的に連続したエネルギーを供給するための連続波レーザとの具体的な構成、とりわけ、パルスレーザの焦点位置、及び、連続波レーザの焦点位置の関係については格別考慮されているわけではなく、図示されているわけでもない。しかして、当該従来技術における他の実施例等を参酌して、その記載から想定される構成を示すと以下のようになるものと思われる。
　図１６に示すように、レーザ駆動光源装置５０においては、イオン性媒体が封入されたチャンバ（プラズマ容器）５２に、該チャンバ５２内で集光するパルスレーザ光５３を照射し、該パルスレーザ光５３の焦点に生成されたプラズマ（火種）５５に対して、同様にチャンバ５２内で前記パルスレーザ光５３の集光点と同じ点に集光する連続状のレーザ光（ＣＷレーザ光）５４を照射するというものである。 However, in Patent Document 1, a specific configuration of a pulse laser as an ignition source for ionizing an ionic medium and a continuous wave laser for supplying substantially continuous energy to the ionized medium In particular, the relationship between the focal position of the pulse laser and the focal position of the continuous wave laser is not particularly considered and is not illustrated. 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. 16, in the laser drive light source device 50, a pulse laser beam 53 condensed in the chamber 52 is irradiated to a chamber (plasma container) 52 in which an ionic medium is enclosed, and the pulse laser beam is irradiated. Similarly, a continuous laser beam (CW laser beam) 54 focused on the same point as the focusing point of the pulsed laser beam 53 in the chamber 52 is applied to the plasma (fire type) 55 generated at the focal point 53. Irradiation.
　しかしながら、このように、点火源に用いるパルスレーザの集光点位置と、イオン化媒体にエネルギーを供給する連続波レーザの集光点位置とが一致する構成とする場合には、パルスレーザによって一旦生成したプラズマが消滅してしまうという問題があることが判明した。このプラズマが消滅するという現象について、図１７および図１８を用いて以下に説明する。 However, when the condensing point position of the pulse laser used for the ignition source and the condensing point position of the continuous wave laser that supplies energy to the ionization medium coincide with each other, it is generated once by the pulse laser. It has been found that there is a problem that the plasma that has been extinguished. The phenomenon that this plasma disappears will be described below with reference to FIGS. 17 and 18.
　図１７に示すように、プラズマ容器５２内のイオン性媒体をイオン化するためのパルスレーザ光５３と、該イオン化媒体のプラズマ５５に照射される連続波レーザ光（以下、ＣＷレーザ光という）５４とは重畳して照射される。
　つまり、期間ｔ１において、図１８（Ａ）に示すように、パルスレーザ光５３の予備放電によってイオン化媒体のプラズマ（火種）５５を生成し、このプラズマ５５に対してＣＷレーザ光５４を照射して該プラズマ５５を維持・生成しようとするものである。
　ところが、続く期間ｔ２においても、上記パルスレーザ光５３による予備放電により生成され、ＣＷレーザ光５４によって生成・維持しようとするプラズマ５５は、パルスレーザ光５３にも晒されることになる。 As shown in FIG. 17, a pulsed laser beam 53 for ionizing an ionic medium in the plasma container 52, and a continuous wave laser beam (hereinafter referred to as CW laser beam) 54 irradiated to the plasma 55 of the ionized medium, Are superimposed and irradiated.
That is, in the period t1, as shown in FIG. 18A, the plasma (fire type) 55 of the ionized medium is generated by the 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.
　図１８（Ｂ）に示すように、該パルスレーザ光５３に晒されるプラズマ５５は、該パルスレーザ光５３によって急激に加熱膨張し、プラズマ５５内の荷電粒子が四方八方に飛散してプラズマが消滅されてしまう。この荷電粒子が消失した空間にＣＷレーザ光５４は印加され続けるが、荷電粒子が消失した状態とは予備電離のない状態と同じであるので、プラズマが生成されることはない。
　即ち、パルスレーザ光５３による予備放電によって生成したプラズマ５５をＣＷレーザ光５４によって維持していこうとしても、同時に照射されるパルスレーザ光５３によって該プラズマ５５が消滅してしまうという問題がある。 As shown in FIG. 18B, 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 to extinguish the plasma. 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.
　このように、パルスレーザ光は、その集光点付近の空間を急激に加熱膨張させてあたかも爆発のような現象を引き起こすことができるので、プラズマ容器内にイオン性媒体の予備放電を形成することに関しては有益である。しかしながら、一方では、ＣＷレーザの集光点位置とパルスレーザの集光点位置とが一致していると、該パルスレーザにより生成しＣＷレーザ光によってせっかく生成・維持されたプラズマが、今度は当該パルスレーザ光によって消滅してしまうという二律背反的な問題がある。 In this way, pulsed laser light 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 ionic medium is formed in the plasma vessel. Is useful. However, on the other hand, if the condensing point position of the CW laser and the condensing point position of the pulse laser coincide with each other, the plasma generated and maintained by the pulse laser and generated and maintained by the CW laser light is There is a contradictory problem that it is extinguished by pulsed laser light.
　上記した問題は、パルスレーザ光の照射時期とＣＷレーザ光の照射時期をずらすことによって解決は図れるものと考えられる。
　しかしながら、パルスレーザ光による予備放電によって生成されるプラズマ（火種）は極めてその寿命が短く、パルスレーザ光の照射を停止した後にＣＷレーザ光を照射しても、その時点ではプラズマ（火種）は消滅していて、該プラズマの維持・生成はできず、どうしても一定期間はパルスレーザ光とＣＷレーザ光とを同時的に照射する必要があるので、根本的な解決とはなりえない。 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.
特表２００９－５３２８２９号公報Special table 2009-532829
　この発明は、上記従来技術の問題点に鑑みて、発光媒体が封入されたプラズマ容器内にパルスレーザ源からのパルスレーザ光を集光照射して予備放電を生成し、該予備放電によって生成されたプラズマにＣＷレーザ源からのＣＷレーザ光を集光照射することによってプラズマ容器内にプラズマを生成・維持するレーザ駆動光源装置において、ＣＷレーザ光によって生成・維持されたプラズマがパルスレーザ光によって消滅することがないようにした構造を提供しようとするものである。 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.
　上記課題を解決するために、この発明に係わるレーザ駆動光源装置は、プラズマ容器内での前記パルスレーザ光の焦点位置とＣＷレーザ光の集光点位置が離隔していることを特徴とする。
　また、前記プラズマ容器は、管球形状であって、前記ＣＷレーザ光の集光点位置が前記プラズマ容器のほぼ中心点に位置していることを特徴とする。
　また、前記プラズマ容器が、凹面反射面を有する本体と、該本体の後方開口に設けられた入射窓と、該本体の前方開口に設けられた出射窓とからなり、前記本体と前記入射窓と前記出射窓によって密閉空間が形成されており、前記ＣＷレーザ光の集光点位置が、前記本体の凹面反射面の焦点位置にあることを特徴とする。
　また、前記パルスレーザ光の集光点位置が前記ＣＷレーザ光の光軸上に位置することを特徴とする。 In order to solve the above-mentioned problems, the laser-driven light source device according to the present invention is characterized in that the focal position of the pulse laser beam and the condensing point position of the CW laser beam in the plasma container are separated from each other.
Further, the plasma container is in a tube shape, and a condensing point position of the CW laser light is located at a substantially central point of the plasma container.
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 point position of the CW laser light is at the focal position of the concave reflecting surface of the main body.
Further, the condensing point position of the pulse laser beam is located on the optical axis of the CW laser beam.
　また、前記パルスレーザ光と前記ＣＷレーザ光は、互いに波長が異なるものであって、同一の集光レンズに入射され、前記パルスレーザ光の集光点と前記ＣＷレーザ光の集光点が前記プラズマ容器内で離隔して集光されることを特徴とする。
　また、前記プラズマ容器は、管球形状であって、前記ＣＷレーザ光の集光点が前記プラズマ容器のほぼ中心点に位置していて、前記プラズマ容器を取り囲むように凹面反射鏡が設けられていて、前記ＣＷレーザ光の集光点が、該凹面反射鏡の焦点にあることを特徴とする。
　また、前記パルスレーザ源及び前記ＣＷレーザ源と、前記集光レンズとの間にダイクロイックミラーが配置され、該ダイクロイックミラーはパルスレーザ光とＣＷレーザ光の一方を透過し、他方を反射するものであることを特徴とする。
　また、前記パルスレーザ源及び前記ＣＷレーザ源と、前記集光レンズとの間に配置されて、前記パルスレーザ光と前記ＣＷレーザ光の一方を透過し、他方を反射する第一のダイクロイックミラーと、前記プラズマ容器の励起光出射側前方に配置されて、前記集光レンズを通過した前記パルスレーザ光及び前記ＣＷレーザ光を前記プラズマ容器に向けて反射し、前記プラズマ容器からの励起光を透過する第二のダイクロイックミラーとを備えていることを特徴とする。
　また、前記パルスレーザ源と前記ＣＷレーザ源とにそれぞれ対応するファイバを有するファイバカプラを備え、該ファイバカプラの合波ファイバを、アクロマティックレンズを介在させて前記集光レンズに対向させてなることを特徴とする。 The pulse laser beam and the CW laser beam have different wavelengths, are incident on the same condenser lens, and the focal point of the pulse laser beam and the focal point of the CW laser beam are It is characterized in that the light is collected separately in the plasma container.
In addition, the plasma container has a tube shape, and the condensing point 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.
Further, a dichroic mirror is disposed between the pulse laser source and the CW laser source and the condenser lens, and the dichroic mirror transmits one of the pulse laser light and the CW laser light and reflects the other. It is characterized by being.
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.
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 made to face the condenser lens with an achromatic lens interposed therebetween. It is characterized by.
　本発明によれば、パルスレーザ光の予備放電により生成されたプラズマが、ＣＷレーザ光によって、パルスレーザ光の集光点位置とは離隔した位置のＣＷレーザ光の集光点位置に移動して、当該集光点位置に存続するので、このＣＷレーザ光によって生成・維持しようとするプラズマが、パルスレーザ光によって消滅されることがなく、安定的にプラズマが維持されるという効果を奏するものである。 According to the present invention, the plasma generated by the preliminary discharge of the pulse laser beam is moved by the CW laser beam to the condensing point position of the CW laser beam at a position separated from the condensing point position of the pulse laser beam. The plasma that is to be generated and maintained by the CW laser beam is not extinguished by the pulse laser beam, and the plasma is stably maintained. is there.
　また、プラズマ容器を管球形状として、ＣＷレーザ光の集光点位置をプラズマ容器のほぼ中心点に位置させたので、高温のプラズマがプラズマ容器中心で存続するため、管壁への偏った熱的影響を防止できる。
　また、プラズマ容器を、凹面反射面を有する本体と、該本体の後方開口に設けられた入射窓と、該本体の前方開口に設けられた出射窓とから構成することで、これら本体部や入射窓や出射窓に石英ガラス以外のセラミックスや金属を使用することができ、プラズマからの高出力のＵＶ光やＶＵＶ光の照射を受けても、紫外線ひずみが生じることのないプラズマ容器を提供することができる。
　また、ＣＷレーザ光の集光点位置が、前記本体の凹面反射面の焦点位置にあることで、ＣＷレーザ光により維持されるプラズマから発生する励起光を、集光光や平行光としてプラズマ容器から外部に出射させることができる。
　また、パルスレーザ光の集光点位置を、ＣＷレーザ光の光軸上に位置するようにすれば、パルスレーザ光によって生成されたプラズマがＣＷレーザ光の集光点位置に移行しやすいという効果がある。
　更には、ダイクロイックミラーを用いてＣＷレーザ光とパルスレーザ光を同軸で同方向から入射させることで、プラズマ容器本体に設けられたレーザ光入射のための開口を１ヶ所にすることができ、ＣＷレーザ光とパルスレーザ光用の入射開口をそれぞれに設ける場合と比較して凹面反射面の面積を拡張することができるため、外部に出射される励起光の光量を増加させることができる。 In addition, since the plasma vessel has a tube shape and the condensing point position of the CW laser light is located at the substantially central point of the plasma vessel, the high temperature plasma continues at the center of the plasma vessel, and thus the biased heat to the tube wall 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 condensing point position of the CW laser light is at the focal position of the concave reflecting surface of the main body, the excitation light generated from the plasma maintained by the CW laser light is converted into the plasma container as the condensed light or parallel light. Can be emitted to the outside.
Further, if the focal point position of the pulse laser beam is positioned on the optical axis of the CW laser beam, the plasma generated by the pulse laser beam can easily shift to the focal point position of the CW laser beam. There is.
Furthermore, by making the CW laser beam and the pulse laser beam incident in the same direction coaxially using a dichroic mirror, the opening for laser beam incidence provided in the plasma vessel main body can be made into one place. Since the area of the concave reflecting surface can be expanded as compared with the case where the incident openings for the laser beam and the pulse laser beam are respectively provided, the amount of excitation light emitted to the outside can be increased.
　また、パルスレーザ光とＣＷレーザ光の波長を異なるものとして、集光レンズの色収差を利用して、プラズマ容器内でパルスレーザ光の集光点とＣＷレーザ光の集光点を離隔させることができる。そして、パルスレーザ光とＣＷレーザ光を同一の集光レンズに入射するものであるので、全体の構造が簡略化される。 Further, it is possible to separate the condensing point of the pulse laser light and the condensing point of the CW laser light in the plasma container by using the chromatic aberration of the condensing lens, assuming that the wavelengths of the pulse laser light and CW laser light are different. it can. Since the pulse laser beam and the CW laser beam are incident on the same condenser lens, the entire structure is simplified.
本発明の第１の実施例に係るレーザ駆動光源装置の説明図。Explanatory drawing of the laser drive light source device which concerns on the 1st Example of this invention. 本発明の第２の実施例の説明図。Explanatory drawing of the 2nd Example of this invention. 本発明の第３の実施例の説明図。Explanatory drawing of the 3rd Example of this invention. 本発明のレーザ駆動光源装置のプラズマの挙動説明図。Explanatory drawing of the behavior of the plasma of the laser drive light source device of this invention. 本発明の第４の実施例の説明図。Explanatory drawing of the 4th Example of this invention. 本発明のレーザ駆動光源装置のプラズマの他の挙動説明図。The other action explanatory view of the plasma of the laser drive light source device of the present invention. 本発明の第５の実施例の説明図。Explanatory drawing of the 5th Example of this invention. 本発明の第６の実施例の説明図。Explanatory drawing of the 6th Example of this invention. 本発明の第７の実施例の説明図。Explanatory drawing of the 7th Example of this invention. 本発明の第８の実施例の説明図。Explanatory drawing of the 8th Example of this invention. 本発明の第９の実施例の説明図。Explanatory drawing of the 9th Example of this invention. 本発明の第１０の実施例の説明図。Explanatory drawing of the 10th Example of this invention. 本発明の第１１の実施例の説明図。Explanatory drawing of the 11th Example of this invention. 本発明の第１２の実施例の説明図。Explanatory drawing of the 12th Example of this invention. 本発明の第１３の実施例の説明図。Explanatory drawing of the 13th Example of this invention. 従来技術から想定されるレーザ駆動光源装置の説明図。Explanatory drawing of the laser drive light source device assumed from a prior art. パルスレーザとＣＷレーザの照射チャート。Irradiation chart of pulse laser and CW laser. 従来のレーザ駆動光源装置のプラズマの挙動説明図。Explanatory drawing of the behavior of the plasma of the conventional laser drive light source device.
　図１に本発明の第１の実施例のレーザ駆動光源装置１が示されていて、プラズマ容器２内には希ガス、水銀等のイオン性の発光媒体が封入されている。このプラズマ容器２は、種々の形態を採用できるが、この実施例では、管球形状をしている。ここで、管球形状とは、ランプ技術における、略球形状や略楕円回転体形状などの発光管形状を意味する。
　このプラズマ容器２には、ここでは図示しないパルスレーザ源からパルスレーザ光３Ｌが該プラズマ容器２内で集光点３ａに集光するように照射されている。
　一方で、同様に図示しないＣＷレーザ源からＣＷレーザ光４Ｌが、プラズマ容器２内に集光照射されていて、該ＣＷレーザ光４Ｌの集光点４ａは、前記パルスレーザ光３Ｌの集光点３ａとは離隔した位置にある。
　そして、この実施例では、前記パルスレーザ光３Ｌの集光点３ａはＣＷレーザ光４Ｌの集光点４ａに対して、該ＣＷレーザ光４Ｌの光軸Ｘ上の前方側（ＣＷレーザ光の進行方向の手前側）に位置しており、また、前記ＣＷレーザ光４Ｌの集光点４ａは前記プラズマ容器２のほぼ中心点に位置している。 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 plasma container 2 is irradiated with a pulse laser beam 3L from a pulse laser source (not shown) so as to be focused on a condensing point 3a in the plasma container 2.
On the other hand, similarly, CW laser light 4L is condensed and irradiated into the plasma container 2 from a CW laser source (not shown), and the condensing point 4a of the CW laser light 4L is the condensing point of the pulse laser light 3L. It is in a position separated from 3a.
In this embodiment, the condensing point 3a of the pulse laser beam 3L is ahead of the condensing point 4a of the CW laser beam 4L on the optical axis X of the CW laser beam 4L (the progress of the CW laser beam). Further, the condensing point 4a of the CW laser light 4L is located substantially at the center point of the plasma vessel 2.
　図２に他の実施例が示されており、この例ではパルスレーザ光３Ｌの集光点３ａは、ＣＷレーザ光４Ｌの集光点４ａに対して光軸Ｘ上の後方側（ＣＷレーザ光の進行方向の先方側）に位置していて、その他の構成については上記図１の実施例と同様である。 FIG. 2 shows another embodiment. In this example, the condensing point 3a of the pulsed laser light 3L is located on the rear side (CW laser light) on the optical axis X with respect to the condensing point 4a of the CW laser light 4L. The other configuration is the same as that of the embodiment of FIG. 1 described above.
　図３に更に他の実施例が示されていて、この例では、パルスレーザ光３Ｌの集光点３ａがＣＷレーザ光４Ｌの光軸Ｘ上にはなく、光軸Ｘとは所定距離だけ離れた位置にある。 FIG. 3 shows another embodiment. In this example, the condensing point 3a of the pulse laser beam 3L is not on the optical axis X of the CW laser beam 4L, and is separated from the optical axis X by a predetermined distance. In the position.
　上記構成において、図４（Ａ）に示すように、パルスレーザ光３Ｌがプラズマ容器２内に集光照射されると、該プラズマ容器２内の集光点３ａの付近に予備放電が生成され、火種７が生成される。そして、この状態でＣＷレーザ光４Ｌが前記火種７の近傍に集光照射されると、図４（Ｂ）に示すように、前記火種７が該ＣＷレーザ光４Ｌの集光点４ａに移動し、該ＣＷレーザ光４Ｌの照射によりプラズマ８が生成され、その後、パルスレーザ光３Ｌの照射を停止するとともに、ＣＷレーザ光４Ｌを継続的に照射することにより該プラズマ８は維持される。
　なお、図１～３の実施例は、パルスレーザ光３ＬとＣＷレーザ光４Ｌが直交して入射するものであるが、その角度は任意のものであってよい。 In the above configuration, as shown in FIG. 4A, when the pulsed laser light 3L is focused and irradiated into the plasma container 2, a preliminary discharge is generated in the vicinity of the focused point 3a in the plasma container 2, Fire type 7 is generated. In this state, when the CW laser light 4L is condensed and irradiated near the fire type 7, the fire type 7 moves to the condensing point 4a of the CW laser light 4L as shown in FIG. 4B. The plasma 8 is generated by the irradiation of the CW laser light 4L, and then the irradiation of the pulse laser light 3L is stopped, and the plasma 8 is maintained by continuously irradiating the CW laser light 4L.
In the embodiment shown in FIGS. 1 to 3, the pulse laser beam 3L and the CW laser beam 4L are incident orthogonally, but the angle may be arbitrary.
　図５～９には、プラズマ容器２が管球形状以外の構造を持つ実施例が示されていて、これらの実施例では、パルスレーザ光とＣＷレーザ光とは同一の光軸上で集光するものである。
　図５は第４の実施例の断面図であり、プラズマ容器２は、円柱形状の本体１０を有しており、その内面に凹面反射面１１が形成されている。この凹面反射面１１は、楕円形状、放物面形状等適宜に選択される。前記本体１０には後方開口１０ａと前方開口１０ｂが形成されていて、後方開口１０ａに対応して入射窓１２が設けられ、前方開口１０ｂに対応して出射窓１３が設けられている。
　そして、本体１０の後方開口１０ａに対応した入射窓１２は、金属製の窓枠部材１４に装着されていて、この窓枠部材１４が、金属筒体１５によって本体１０に取り付けられている。これら凹面反射面１１を有する本体１０と、入射窓１２と、出射窓１３とによって密閉空間が形成されており、この密閉空間内に発光元素が封入されていて、プラズマ容器２が構成されている。 FIGS. 5 to 9 show embodiments in which the plasma container 2 has a structure other than a tube shape. In these embodiments, the pulse laser beam and the CW laser beam are condensed on the same optical axis. To do.
FIG. 5 is a cross-sectional view of the fourth embodiment. The plasma vessel 2 has a cylindrical main body 10 with a concave reflecting surface 11 formed on the inner surface thereof. The concave reflecting surface 11 is appropriately selected such as an elliptical shape or a parabolic shape. The main body 10 is formed with a rear opening 10a and a front opening 10b. An entrance window 12 is provided corresponding to the rear opening 10a, and an exit window 13 is provided corresponding to the front opening 10b.
The incident window 12 corresponding to the rear opening 10 a of the main body 10 is attached to a metal window frame member 14, and the window frame member 14 is attached to the main body 10 by a metal cylinder 15. A sealed space is formed by the main body 10 having the concave reflecting surface 11, the entrance window 12, and the exit window 13, and a light emitting element is enclosed in the sealed space, thereby forming the plasma container 2. .
　上記構成のプラズマ容器２に対して、パルスレーザ光３ＬとＣＷレーザ光４Ｌは、共に当該プラズマ容器２内で集光するが、その集光点３ａと集光点４ａとは離隔した位置にある。そして、ＣＷレーザ光４Ｌの集光点４ａは、プラズマ容器２の凹面反射面１１の焦点Ｆ位置と一致している。そして、この実施例では、パルスレーザ光３Ｌの集光点３ａは、ＣＷレーザ光４Ｌの光軸Ｘ上においてその集光点４ａから前方側（ＣＷレーザ光の進行方向の手前側）に離隔している。
　図５には、このような配置を実現する構成の一例が示されていて、ＣＷレーザ光４Ｌの光路中にダイクロイックミラー３５が配置されている。このダイクロイックミラー３５は、ＣＷレーザ光４Ｌは透過して、パルスレーザ光３Ｌは反射するものである。 The pulse laser beam 3L and the CW laser beam 4L are both condensed in the plasma vessel 2 with respect to the plasma vessel 2 having the above-described configuration, but the condensing point 3a and the condensing point 4a are located apart from each other. . The condensing point 4a of the CW laser beam 4L coincides with the focal point F position of the concave reflecting surface 11 of the plasma container 2. In this embodiment, the condensing point 3a of the pulsed laser light 3L is separated from the condensing point 4a on the optical axis X of the CW laser light 4L to the front side (front side in the traveling direction of the CW laser light). ing.
FIG. 5 shows an example of a configuration that realizes such an arrangement, and a dichroic mirror 35 is arranged in the optical path of the CW laser beam 4L. The dichroic mirror 35 transmits the CW laser beam 4L and reflects the pulse laser beam 3L.
　ＣＷレーザ光４Ｌは、集光レンズ１７によって集光されつつ、ダイクロイックミラー３５を透過してプラズマ容器２の入射窓１２から入射し、凹面反射面１１の焦点Ｆ位置に集光する。つまり、ＣＷレーザ光４Ｌの集光点４ａは、凹面反射面１１の焦点Ｆと一致している。
　一方、パルスレーザ光３Ｌは、集光レンズ１８によって集光されつつ、ダイクロイックミラー３５に対して、図５の下方から照射され、これにより反射されて光路を変えて入射窓１２からプラズマ容器２内に入射する。
　このパルスレーザ光３Ｌの集光点３ａは、上記したように、ＣＷレーザ光４Ｌの光軸Ｘ上においてその焦点４ａの前方側（手前側）に離隔している。
　プラズマ容器２内でＣＷレーザ光４Ｌにより生成・維持されるプラズマによって励起された励起光ＥＬは、凹面反射面１１によって反射されて出射窓１３を介して外部に出射される。 The CW laser beam 4 </ b> L is collected by the condenser lens 17, passes through the dichroic mirror 35, enters from the incident window 12 of the plasma container 2, and is collected at the focal point F position of the concave reflecting surface 11. That is, the condensing point 4a of the CW laser beam 4L coincides with the focal point F of the concave reflecting surface 11.
On the other hand, the pulse laser beam 3L is irradiated from the lower side of FIG. 5 to the dichroic mirror 35 while being condensed by the condenser lens 18, and is reflected thereby to change the optical path from the incident window 12 into the plasma container 2. Is incident on.
As described above, the condensing point 3a of the pulse laser beam 3L is separated on the front side (near side) of the focal point 4a on the optical axis X of the CW laser beam 4L.
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 11 and emitted to the outside through the emission window 13.
　上記構成におけるプラズマの挙動を図６により説明する。図６に示すように、パルスレーザ光３Ｌがプラズマ容器２内に集光照射されると、該プラズマ容器２内の集光点３ａの付近に予備放電が生成され、火種７が生成される。そして、この状態でＣＷレーザ光４Ｌが前記火種７の近傍に集光照射されると、前記火種７が該ＣＷレーザ光４Ｌの集光点４ａに移動し、該ＣＷレーザ光４Ｌの照射によりプラズマ８が生成される。その後、パルスレーザ光３Ｌの照射を停止するとともに、ＣＷレーザ光４Ｌを継続的に照射することにより該プラズマ８はＣＷレーザ光４Ｌの集光点４ａの位置で維持されるものである。 The behavior of plasma in the above configuration will be described with reference to FIG. As shown in FIG. 6, when the pulsed laser light 3 </ b> L is condensed and irradiated into the plasma container 2, a preliminary discharge is generated near the condensing point 3 a in the plasma container 2, and a fire type 7 is generated. In this state, when the CW laser beam 4L is condensed and irradiated in the vicinity of the fire type 7, the fire type 7 moves to the condensing point 4a of the CW laser beam 4L, and plasma is generated by the irradiation of the CW laser beam 4L. 8 is generated. Thereafter, the irradiation of the pulse laser beam 3L is stopped and the CW laser beam 4L is continuously irradiated to maintain the plasma 8 at the position of the condensing point 4a of the CW laser beam 4L.
　図７に更に他の第５の実施例が示されていて、この例では、ＣＷレーザ光はプラズマ容器の後方から入射し、パルスレーザ光は前方から入射する例である。
　つまり、ＣＷレーザ光４Ｌは、プラズマ容器２の入射窓１２を介して入射するが、このＣＷレーザ光４Ｌの集光点４ａは、凹面反射面１１の焦点Ｆ位置に一致するように配置されていて、ＣＷレーザ光４Ｌは、凹面反射面１１の焦点Ｆ位置に集光する。
　そして、プラズマ容器２の前方（出射側）には、ダイクロイックミラー３５が配置されていて、このダイクロイックミラー３５は、パルスレーザ光３Ｌを反射し、プラズマ容器２からの励起光ＥＬを透過するものである。 FIG. 7 shows still another fifth embodiment. In this example, the CW laser light is incident from the rear of the plasma container, and the pulsed laser light is incident from the front.
That is, the CW laser light 4L is incident through the incident window 12 of the plasma container 2, and the condensing point 4a of the CW laser light 4L is disposed so as to coincide with the focal point F position of the concave reflecting surface 11. Thus, the CW laser beam 4L is condensed at the focal point F position of the concave reflecting surface 11.
A dichroic mirror 35 is disposed in front of the plasma container 2 (on the emission side). The dichroic mirror 35 reflects the pulse laser light 3L and transmits the excitation light EL from the plasma container 2. is there.
　一方、パルスレーザ光３Ｌは、集光レンズ１８によって集光されつつ、ダイクロイックミラー３５に対して、図７の上方から照射され、このダイクロイックミラー３５で反射されて光路を変更し、プラズマ容器２の出射窓１３から入射し、内部で集光する。このパルスレーザ光３Ｌの集光点３ａは、ＣＷレーザ光４Ｌの光軸Ｘ上において、ＣＷレーザ光４Ｌの集光点４ａ（凹面反射面１１の焦点Ｆ）に対して後方側（ＣＷレーザ光の進行方向の先方側）に離隔している。
　そして、ＣＷレーザ光４Ｌにより生成・維持されるプラズマによって励起された励起光ＥＬは、凹面反射面１１によって反射されて出射窓１３を介して出射され、ダイクロイックミラー３５を透過して外部に出射される。 On the other hand, the pulse laser light 3L is irradiated from the upper side of FIG. 7 while being condensed by the condenser lens 18 and is reflected by the dichroic mirror 35 to change the optical path. The light enters from the exit window 13 and is condensed inside. The condensing point 3a of the pulsed laser light 3L is on the rear side (CW laser light) with respect to the condensing point 4a of the CW laser light 4L (focal point F of the concave reflecting surface 11) on the optical axis X of the CW laser light 4L. It is separated from the other side of the direction of travel.
Then, the excitation light EL excited by the plasma generated and maintained by the CW laser light 4L is reflected by the concave reflecting surface 11 and emitted through the emission window 13, and is transmitted through the dichroic mirror 35 and emitted to the outside. The
　図８、図９には、更に別の実施例として、ＣＷレーザ光４Ｌがプラズマ容器２の前方から入射し、パルスレーザ光３Ｌが後方から入射する例が示されている。
　図８に示す第６の実施例においては、プラズマ容器２の前方に、ＣＷレーザ光４Ｌを反射し、励起光ＥＬを透過するダイクロイックミラー３５が配置されている。
　パルスレーザ光３Ｌは、プラズマ容器２の入射窓１２から入射して、集光点３ａに集光する。この集光点３ａは、プラズマ容器２の凹面反射面１１の焦点Ｆとは異なる位置にある。
　一方、ＣＷレーザ光４Ｌは、集光レンズ１７によって集光されつつ、ダイクロイックミラー３５に照射され、ここで反射されて、光路を変更してプラズマ容器２の出射窓１３からプラズマ容器２内に入射する。このとき、ＣＷレーザ光４Ｌの集光点４ａは、凹面反射面１１の焦点Ｆ位置に一致するように配置されていて、ＣＷレーザ光４Ｌは、凹面反射面１１の焦点Ｆ位置に集光する。
　そして、ＣＷレーザ光４Ｌにより生成・維持されるプラズマによって励起された励起光ＥＬは、凹面反射面１１によって反射されて出射窓１３を介して出射され、ダイクロイックミラー３５を透過して外部に出射される。 FIG. 8 and FIG. 9 show an example in which the CW laser light 4L is incident from the front of the plasma container 2 and the pulsed laser light 3L is incident from the rear as yet another embodiment.
In the sixth embodiment shown in FIG. 8, a dichroic mirror 35 that reflects the CW laser light 4L and transmits the excitation light EL is disposed in front of the plasma container 2.
The pulse laser beam 3L is incident from the incident window 12 of the plasma container 2 and is condensed at the condensing point 3a. This condensing point 3 a is at a position different from the focal point F of the concave reflecting surface 11 of the plasma container 2.
On the other hand, the CW laser beam 4L is irradiated on the dichroic mirror 35 while being collected by the condenser lens 17, reflected there, and enters the plasma vessel 2 from the emission window 13 of the plasma vessel 2 by changing the optical path. To do. At this time, the condensing point 4a of the CW laser light 4L is arranged so as to coincide with the focal point F position of the concave reflecting surface 11, and the CW laser light 4L is condensed at the focal point F position of the concave reflecting surface 11. .
Then, the excitation light EL excited by the plasma generated and maintained by the CW laser light 4L is reflected by the concave reflecting surface 11 and emitted through the emission window 13, and is transmitted through the dichroic mirror 35 and emitted to the outside. The
　図８の第６の実施例では、ＣＷレーザ光４Ｌが集光されつつプラズマ容器２に入射するものであるのに対して、図９の第７の実施例では、ＣＷレーザ光４Ｌは集光されることなく平行光としてプラズマ容器２に入射する例である。
　ダイクロイックミラー３５によって反射されて平行光としてプラズマ容器２に入射したＣＷレーザ光４Ｌは、凹面反射面１１によって反射されて、その焦点Ｆに集光する。つまり、この場合も、ＣＷレーザ光４Ｌの集光点４ａと凹面反射面１１の焦点Ｆとは一致していることになる。
　このように、平行ＣＷレーザ光４Ｌを焦点Ｆで集光するためには、凹面反射面１１を放物面で形成することで実現できる。
　その他の構成については上記図８の第６の実施例と同様である。
　この実施例によれば、ＣＷレーザ光４Ｌを集光する集光レンズ１７を省略することができるという利点がある。 In the sixth embodiment of FIG. 8, the CW laser light 4L is incident on the plasma vessel 2 while being condensed, whereas in the seventh embodiment of FIG. 9, the CW laser light 4L is condensed. It is an example which injects into the plasma container 2 as parallel light, without being carried out.
The CW laser light 4L reflected by the dichroic mirror 35 and incident on the plasma container 2 as parallel light is reflected by the concave reflecting surface 11 and condensed at the focal point F. That is, also in this case, the condensing point 4a of the CW laser light 4L and the focal point F of the concave reflecting surface 11 are coincident.
Thus, in order to condense the parallel CW laser beam 4L at the focal point F, it can be realized by forming the concave reflecting surface 11 with a parabolic surface.
Other configurations are the same as those of the sixth embodiment shown in FIG.
According to this embodiment, there is an advantage that the condenser lens 17 for condensing the CW laser light 4L can be omitted.
　図１０以下の実施例は、パルスレーザ光の集光点とＣＷレーザ光の集光点の位置を離隔する手段として、集光レンズの色収差を利用したものである。
　図１０に示された、本発明の第８の実施例のレーザ駆動光源装置１は、パルスレーザ源３とＣＷレーザ源４とを備えており、これらパルスレーザ源３からのパルスレーザ光３Ｌと、ＣＷレーザ源４からのＣＷレーザ光４Ｌは、互いにその波長が異なっている。
　そして、この実施例では、ＣＷレーザ光４Ｌの波長がパルスレーザ光３Ｌの波長よりも長いという前提で説明する。例えば、ＣＷレーザ光４Ｌの波長が１０６４±５ｎｍで、パルスレーザ光３Ｌの波長が５３２±５ｎｍの場合や、あるいは、ＣＷレーザ光４Ｌの波長が１５５０±５ｎｍで、パルスレーザ光３Ｌの波長が５２３．５±５ｎｍの場合でなどである。 In the embodiment shown in FIG. 10 and subsequent figures, the chromatic aberration of the condensing lens is used as means for separating the condensing point of the pulse laser beam and the condensing point of the CW laser beam.
The laser drive light source device 1 of the eighth embodiment of the present invention shown in FIG. 10 includes a pulse laser source 3 and a CW laser source 4, and the pulse laser light 3L from these pulse laser sources 3 The CW laser beams 4L from the CW laser source 4 have different wavelengths.
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.
　前記パルスレーザ源３からのパルスレーザ光３Ｌと、前記ＣＷレーザ源４からのＣＷレーザ光４Ｌは、同一の集光レンズ５に照射される。これを実現するために、パレスレーザ源３及びＣＷレーザ源４と、集光レンズ５との間にはダイクロイックミラー６が配置されている。
　このダイクロイックミラー６は、パルスレーザ光３Ｌを反射し、ＣＷレーザ光４Ｌを透過するものである。
　勿論、パルスレーザ源３とＣＷレーザ源４の配置を逆にして、ダイクロイックミラー６を、パルスレーザ光３Ｌを透過し、ＣＷレーザ光４Ｌを反射するものとすることもできる。 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. In order to realize this, a dichroic mirror 6 is disposed 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.
　このような配置により、パルスレーザ源３からパルスレーザ光３Ｌは、ダイクロイックミラー６により反射され、集光レンズ５によって管球形状のプラズマ容器２内で集光点３ａに集光される。
　一方で、ＣＷレーザ源４からＣＷレーザ光４Ｌは、ダイクロイックミラー６を透過し、同じ集光レンズ５によってプラズマ容器２内で集光点４ａに集光される。このＣＷレーザ光４Ｌの集光点４ａは、前記パルスレーザ光３Ｌの集光点３ａとは離隔した位置になる。 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 condenser lens 5 on the condensing point 3a in the tube-shaped 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.
　このように、同一の集光レンズ５によって集光されるパルスレーザ光３Ｌの集光点３ａとＣＷレーザ光４Ｌの集光点４ａが異なる位置になるのは、集光レンズ５の色収差によるものである。
　この色収差を有する集光レンズ５によって、パルスレーザ光３Ｌ及びＣＷレーザ光４Ｌは、それぞれの波長に応じた集光点に集光する。この集光レンズ５の材質は、例えば、ＢＫ－７、石英、フッ化カルシウムなどである。
　そして、この実施例では、波長の短いパルスレーザ光３Ｌの集光点３ａは、波長の長いＣＷレーザ光４Ｌの集光点４ａに対して、該ＣＷレーザ光４Ｌの光軸上の後方側（レーザ光の進行方向の手前側）に位置している。
　このとき、前記ＣＷレーザ光４Ｌの集光点４ａが前記プラズマ容器２のほぼ中心点に位置するように配置することが望ましい。 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 located behind the condensing point 4a of the long-wavelength CW laser light 4L on the optical axis of the CW laser light 4L ( It is located on the front side of the traveling direction of the laser beam.
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.
　また、前記プラズマ容器２を取り囲むように凹面反射鏡９が設けられていて、ＣＷレーザ光４Ｌの集光点４ａはこの凹面反射鏡９の焦点に位置している。
　これにより、プラズマ容器２内で発生したプラズマにより生成される励起光ＥＬは、この凹面反射鏡９によって反射されて、その前面開口から出射される。このとき、励起光ＥＬを平行光として取り出すか、集光光として取り出すかは、凹面反射鏡９の形状によって選択される。この実施例では、凹面反射鏡９が放物面鏡として構成され、励起光ＥＬが平行光として出射されるものが示されている。 Further, a concave reflecting mirror 9 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 9.
Thereby, the excitation light EL generated by the plasma generated in the plasma container 2 is reflected by the concave reflecting mirror 9 and emitted from the front opening. At this time, whether to extract the excitation light EL as parallel light or as condensed light is selected depending on the shape of the concave reflecting mirror 9. In this embodiment, the concave reflecting mirror 9 is configured as a parabolic mirror, and the excitation light EL is emitted as parallel light.
　この構成におけるパルスレーザ光３ＬとＣＷレーザ光４Ｌによるプラズマ容器２内でのプラズマ発生の挙動は、上記図６に関する説明と同様である。 The behavior of the plasma generation in the plasma container 2 by the pulse laser beam 3L and the CW laser beam 4L in this configuration is the same as described with reference to FIG.
　図１１の第９の実施例は、プラズマ容器２が管球形状以外の構造を持つ例である。
　プラズマ容器２は、円柱形状の本体２０を有しており、その内面に凹面反射面２１が形成されている。この凹面反射面２１は、楕円形状、放物面形状等適宜に選択される。前記本体２０には後方開口２０ａと前方開口２０ｂが形成されていて、中心部にはレーザ光通過用の貫通孔２２が形成されている。そして、後方開口２０ａに対応して入射窓２３が設けられ、前方開口２０ｂに対応して出射窓２４が設けられている。
　本体２０の後方開口２０ａに対応した入射窓２３は、金属製の窓枠部材２５に装着されていて、この窓枠部材２５が、金属筒体２６によって本体２０に取り付けられている。同様に、前方開口２０ｂに対応した出射窓２４は、金属製の窓枠部材２７に装着されていて、この窓枠部材２７が、金属筒体２８によって本体２０に取り付けられている。
　これら凹面反射面２１を有する本体２０と、入射窓２３と、出射窓２４とによって密閉空間Ｓが形成されており、この密閉空間Ｓ内に発光元素が封入されていて、プラズマ容器２が構成されている。 The ninth embodiment of FIG. 11 is an example in which the plasma container 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.
　このような構成のプラズマ容器２に対して、ＣＷレーザ光４Ｌは、ダイクロイックミラー６を透過し、集光レンズ５によって集光されつつ、プラズマ容器２の入射窓２３から入射し、プラズマ容器２内で集光する。
　一方、パルスレーザ光３Ｌは、ダイクロイックミラー６により反射されて光路を変え、同じ集光レンズ５によって集光されて入射窓２３からプラズマ容器２内に入射し、該プラズマ容器２内で集光する。
　このように、パルスレーザ光３ＬとＣＷレーザ光４Ｌは、ダイクロイックミラー６を経て、同一の集光レンズ５によって、共に当該プラズマ容器２内で集光するが、集光レンズ５の色収差に基づいて、その集光点３ａと集光点４ａは離隔した位置になる。
　この実施例では、パルスレーザ光３Ｌの集光点３ａは、ＣＷレーザ光４Ｌの集光点４ａから光軸上において後方側（レーザ光の進行方向の手前側）に離隔している。
　そして、この場合、ＣＷレーザ光４の集光点４ａは、プラズマ容器２の凹面反射面２１の焦点と一致している。 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.
　プラズマ容器２内でＣＷレーザ光４Ｌにより生成・維持されるプラズマによって励起された励起光ＥＬは、凹面反射面２１によって反射されて出射窓２４を介して外部に出射される。 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.
　この第９の実施例によれば、プラズマ容器２を構成する本体部２０や入射窓２３や出射窓２４に石英ガラス以外のセラミックスや金属を使用することができ、ＵＶ光やＶＵＶ光を励起光とする場合にも、プラズマからの高出力のＵＶ光やＶＵＶ光の照射を受けても、紫外線ひずみが生じることのないプラズマ容器を提供することができる。 According to the ninth 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 constituting 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.
　図１２に示す第１０の実施例では、パルスレーザ光及びＣＷレーザ光がともに、凹面反射鏡の前面開口側からプラズマ容器に入射する例である。
　パルスレーザ源３及びＣＷレーザ源４と、集光レンズ５との間には、第一のダイクロイックミラー３６が配置されていて、この第１のダイクロイックミラー３６は、パルスレーザ光３Ｌを反射し、ＣＷレーザ光４Ｌを透過するものである。
　勿論、パルスレーザ源３とＣＷレーザ源４の配置を逆にして、第１のダイクロイックミラー３６を、パルスレーザ光３Ｌを透過し、ＣＷレーザ光４Ｌを反射するものとすることができることは、図１０の第８の実施例と同様である。 The tenth embodiment shown in FIG. 12 is an example in which both pulsed laser light and CW laser light are incident on the plasma container from the front opening side of the concave reflecting mirror.
A first dichroic mirror 36 is disposed between the pulse laser source 3 and the CW laser source 4 and the condenser lens 5, and the first dichroic mirror 36 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 36 can transmit the pulse laser beam 3L and reflect the CW laser beam 4L. This is the same as the tenth eighth embodiment.
　そして、プラズマ容器２を取り囲む凹面反射鏡９の前方、即ち、励起光出射側の前方に第２のダイクロイックミラー３７が配置されていて、この第２のダイクロイックミラー３７は、パルスレーザ光３Ｌ及びＣＷレーザ光４Ｌを反射し、プラズマ容器２からの励起光ＥＬを透過するものである。
　この構成により、パルスレーザ源３からのパルスレーザ光３Ｌ及びＣＷレーザ源４からのＣＷレーザ光４Ｌは、共に同じ集光レンズ５を通過して第２のダイクロイックミラー３７に至り、ここで反射されてプラズマ容器２に向かう。
　そして、プラズマ容器２内でそれぞれ集光するが、それぞれの集光点３ａ、４ａは、波長に応じて異なる位置に離隔している。即ち、パルスレーザ光３Ｌの集光点３ａは、ＣＷレーザ光４Ｌの集光点４ａよりも、光軸上においてレーザ光の進行方向の手前側に位置する。 A second dichroic mirror 37 is disposed in front of the concave reflecting mirror 9 surrounding the plasma container 2, that is, in front of the excitation light emission side. 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 37, where they are reflected. To the plasma vessel 2.
Then, the light is condensed in the plasma container 2, but 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.
　この実施例においても、ＣＷレーザ光４Ｌの集光点４ａは、凹面反射鏡９の焦点に位置している。これにより、プラズマ容器２内で発生したプラズマに基づく励起光ＥＬは、凹面反射鏡９により反射されて、その前面開口から出射される。この励起光ＥＬは、第２のダイクロイックミラー３７を透過して、外部に出射される。 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 9. Thereby, the excitation light EL based on the plasma generated in the plasma container 2 is reflected by the concave reflecting mirror 9 and emitted from the front opening. This excitation light EL passes through the second dichroic mirror 37 and is emitted to the outside.
　図１３に示す第１１の実施例では、図１２の第１０の実施例とは、プラズマ容器２の形状が異なる。
　即ち、プラズマ容器２を構成する円筒状の本体３０には、前面側に凹面反射面３１が形成されていて、その前面開口には前面窓３２が設けられ、これら本体３０と前面窓３２により、密閉空間が形成されていて、その内部には発光元素が封入されている。
　その他の構成は、図１２の第１０の実施例と同様である。 The eleventh embodiment shown in FIG. 13 differs from the tenth embodiment of FIG. 12 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 tenth embodiment of FIG.
　パルスレーザ光３Ｌ及びＣＷレーザ光４Ｌは、それぞれ、パルスレーザ源３（ＣＷレーザ源４）→第１のダイクロイックミラー３６→集光レンズ５→第２のダイクロイックミラー３７→前面窓３２を経てプラズマ容器２内で集光する。このとき、パルスレーザ光３Ｌの集光点３ａと、ＣＷレーザ光４Ｌの集光点４ａとは、それぞれの波長に応じて離隔しており、この第１１の実施例では、パルスレーザ光３Ｌの集光点３ａが、レーザ光の光軸上でＣＷレーザ光４Ｌの集光点４ａよりもレーザ光の進行方向で手前側に位置することは、前記第１０の実施例と同様である。
　そして、プラズマ容器２内で発生した励起光ＥＬは、前面窓３２から出射して、第２のダイクロイックミラー３７を透過して外部に出射される。 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 36 → the condensing lens 5 → the second dichroic mirror 37 → the front window 32. 2 to collect light. At this time, the condensing point 3a of the pulse laser light 3L and the condensing point 4a of the CW laser light 4L are separated according to the respective wavelengths. In the eleventh embodiment, the condensing point 3a of the pulse laser light 3L As in the tenth embodiment, the condensing point 3a is positioned on the near side in the traveling 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 37, and is emitted to the outside.
　図１４に示す第１２の実施例では、パルスレーザ光３ＬとＣＷレーザ光４Ｌを同じ集光レンズ５に導く手段として、ファイバカプラ４０を用いた例である。
　ここで、ファイバカプラとは、波長の同じ光を合流若しくは分岐させ、または、波長の異なる光を合波若しくは分波するという機能を有する光学部品であり、本発明においては、異なる波長のレーザ光を合波するために使用する。
　パルスレーザ源３からのパルスレーザ光３Ｌと、ＣＷレーザ源４からのＣＷレーザ光４Ｌをファイバカプラ４０のそれぞれのファイバ４１、４２の一端に入射し、これら波長の異なるレーザ光を合波する。そして合波ファイバ４３から出射する合波されたレーザ光を、アクロマティックレンズ（アクロマートレンズ）４５を介して集光レンズ５に入射させる。 In the twelfth embodiment shown in FIG. 14, a fiber coupler 40 is used as 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.
　ここで、アクロマティックレンズ４５とは、光学特性の異なるレンズを樹脂接合して貼り合わせたもので、色収差の補正に使用される。本発明では、この性質を利用し、ファイバカプラ４０の合波ファイバ４３から出射される光を平行光にしてから集光レンズ５に入射させる。アクロマティックレンズ４５を利用することにより、集光レンズ５にレーザ光を平行光として入射させることができるようになり、レーザ光の集光点の位置合わせが容易になる。 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.
　以上説明した第８～第１２の実施例では、ＣＷレーザ光の波長が、パルスレーザ光の波長よりも長い例で説明したが、図１５の第１３の実施例は、ＣＷレーザ光の波長がパルスレーザ光の波長よりも短い場合の例である。
　この場合、パルスレーザ光３Ｌの集光点３ａとＣＷレーザ光４Ｌの集光点４ａが、異なる位置に離隔していることは同じであるが、パルスレーザ光３Ｌの集光点３ａが、光軸上でＣＷレーザ光４Ｌの集光点４ａよりも前方側（レーザ光の進行方向で先方側）に離隔している。
　このとき、ＣＷレーザ光４Ｌの集光点４ａをプラズマ容器２の凹面反射面２１の焦点に位置させることは他の実施例と同様である。 In the eighth to twelfth 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 thirteenth embodiment in 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.
　以下、パルスレーザ光とＣＷレーザ光の波長の違いによる集光点の離隔距離を評価した。
（１）ＣＷレーザ光の波長　：1064±5nm
　　　パルスレーザ光の波長：532±5nm
　　　集光レンズ：ソーラボ社製　LA1472（BK－7製、F＠587.6nm=20mm、R=10.3　＋0.0‐0.1mm）
 
　平凸レンズの焦点距離F=R／（n－1）
　　　R：レンズの曲率半径
　　　n（λ）：屈折率
 
　ＣＷレーザ光（1064±5nm）の焦点距離F1=20.328～20.333mm
　パルスレーザ光（532±5nm）の焦点距離F2=19.817～19.838mm）
 
　両者の差（F1－F2）がＣＷレーザ光とパルスレーザ光の集光点間の離間距離ΔＦである。
　　離間距離ΔＦ＝0.49～0.52mm 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 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レーザ光の波長　：1550±5nm
　　　パルスレーザ光の波長：523.5±5nm
　　　集光レンズ：ソーラボ社製　LA1255（BK－7製、F＠587.6nm=50mm、R=25.8　＋0.0‐0.1mm）
 
　ＣＷレーザ光（1550±5nm）の焦点距離F1=51.526～51.539mm
　パルスレーザ光（523.5±5nm）の焦点距離F2=49.592～49.647mm）
 
　　離間距離ΔＦ＝1.88～1.95mm (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
　上記のように、本発明においては、プラズマ容器内でのパルスレーザ光の集光点位置とＣＷレーザ光の集光点位置が離隔しているので、パルスレーザ光の集光点近傍に生成される予備電離に伴うプラズマの火種が、ＣＷレーザ光の集光点位置に移動してプラズマを生成するため、パルスレーザ光がこのプラズマに当たることがなく、せっかく生成されたプラズマがパルスレーザ光によって消滅させられるようなことがなく、安定的にプラズマを生成・維持することができる。
　また、集光点を離隔する手段として、波長の異なるパルスレーザ光とＣＷレーザ光を同一の集光レンズに入射して、該集光レンズの色収差を利用することで、全体構造が簡略化される。 As described above, in the present invention, since the condensing point position of the pulse laser light in the plasma container and the condensing point position of the CW laser light are separated from each other, they are generated near the condensing point of the pulse laser light. Since the plasma fire associated with preionization moves to the condensing point of the CW laser beam and generates plasma, the pulsed laser beam does not hit this plasma, and the generated plasma is extinguished by the pulsed laser beam. The plasma can be generated and maintained stably without being generated.
In addition, as a means for separating the condensing points, the entire structure is simplified by making pulse laser light and CW laser light having different wavelengths incident on the same condensing lens and utilizing the chromatic aberration of the condensing lens. The
　１　　　　レーザ駆動光源装置
　２　　　　プラズマ容器
　３　　　　パルスレーザ源
　３Ｌ　　　パルスレーザ光
　３ａ　　　パルスレーザ光の集光点
　４　　　　ＣＷレーザ源
　４Ｌ　　　ＣＷレーザ光
　４ａ　　　ＣＷレーザ光の集光点
　７　　　　火種
　８　　　　プラズマ
　９　　　　凹面反射鏡
　１０　　　本体
　１０ａ　　後方開口
　１０ｂ　　前方開口
　１１　　　凹面反射面
　１２　　　入射窓
　１３　　　出射窓
　１４　　　窓枠部材
　１５　　　金属筒体
　１７　　　（ＣＷレーザ光の）集光レンズ
　１８　　　（パルスレーザ光の）集光レンズ
　２０　　　本体
　２０ａ　　後方開口
　２０ｂ　　前方開口
　２１　　　凹面反射面
　２２　　　貫通孔
　２３　　　入射窓
　２４　　　出射窓
　２５　　　（入射窓用）窓枠部材
　２６　　　金属筒体
　２７　　　（出射窓用）窓枠部材
　２８　　　金属筒体
　３０　　　本体
　３１　　　凹面反射面
　３２　　　前面窓
　３５　　　ダイクロイックミラー
　３６　　　第１のダイクロイックミラー
　３７　　　第２のダイクロイックミラー
　４０　　　ファイバカプラ
　４１，４２　ファイバ
　４３　　　合波ファイバ
　４５　　　アクロマティックレンズ
　Ｘ　　　　ＣＷレーザ光の光軸
　Ｆ　　　　凹面反射面の焦点
　ＥＬ　　　励起光
 
 
  DESCRIPTION OF SYMBOLS 1 Laser drive light source device 2 Plasma container 3 Pulse laser source 3L Pulse laser beam 3a Condensing point of pulse laser beam 4 CW laser source 4L CW laser beam 4a Condensing point of CW laser beam 7 Fire type 8 Plasma 9 Concave reflector 10 Main body 10a rear opening 10b front opening 11 concave reflecting surface 12 entrance window 13 exit window 14 window frame member 15 metal cylinder 17 condensing lens 18 (for CW laser light) condensing lens 20 (for pulse laser light) 20 main body 20a rear opening 20b Front opening 21 Concave reflection 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 30 Main body 31 Concave reflection surface 32 Front window 35 Dichroic mirror 36 First dichroic mirror Mirror 37 second dichroic mirror 40 fiber coupler 41 fiber 43 multiplexing fiber 45 achromatic lens X CW focal EL excitation light optical axis F concave reflecting surface of the laser beam

Claims (10)

  1. 　発光媒体が封入されたプラズマ容器内にパルスレーザ源からのパルスレーザ光を集光照射して予備放電を生成し、該予備放電によって生成されたプラズマにＣＷレーザ源からのＣＷレーザ光を集光照射することによってプラズマ容器内にプラズマを生成・維持するレーザ駆動光源装置において、
    　前記パルスレーザ光の焦点位置と前記ＣＷレーザ光の集光点位置が離隔していることを特徴とするレーザ駆動光源装置。     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,
    A laser-driven light source device, wherein a focal position of the pulse laser beam and a condensing point position of the CW laser beam are separated from each other.
  2. 　前記プラズマ容器は、管球形状であって、前記ＣＷレーザ光の集光点位置が前記プラズマ容器のほぼ中心点に位置していることを特徴とする請求項１に記載のレーザ駆動光源装置。 The laser-driven light source device according to claim 1, wherein the plasma container has a tube shape, and a condensing point position of the CW laser light is located at a substantially central point of the plasma container.
  3. 　前記プラズマ容器が、凹面反射面を有する本体と、該本体の後方開口に設けられた入射窓と、該本体の前方開口に設けられた出射窓とからなり、前記本体と前記入射窓と前記出射窓によって密閉空間が形成されており、
    　前記ＣＷレーザ光の集光点位置が、前記本体の凹面反射面の焦点位置にあることを特徴とする請求項１に記載のレーザ駆動光源装置。     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,
    2. The laser-driven light source device according to claim 1, wherein a condensing point position of the CW laser light is at a focal position of a concave reflecting surface of the main body.
  4. 　前記パルスレーザ光の集光点位置が前記ＣＷレーザ光の光軸上に位置することを特徴とする請求項１～３のいずれかに記載のレーザ駆動光源装置。 The laser-driven light source device according to any one of claims 1 to 3, wherein a condensing point position of the pulse laser light is located on an optical axis of the CW laser light.
  5. 　前記パルスレーザ光と前記ＣＷレーザ光は、互いに波長が異なるものであって、同一の集光レンズに入射され、
    　前記パルスレーザ光の集光点と前記ＣＷレーザ光の集光点が前記プラズマ容器内で離隔して集光される、
    ことを特徴とする請求項１に記載のレーザ駆動光源装置。     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,
    The laser-driven light source device according to claim 1.
  6. 　前記プラズマ容器は、管球形状であって、前記ＣＷレーザ光の集光点が前記プラズマ容器のほぼ中心点に位置していて、
    　前記プラズマ容器を取り囲むように凹面反射鏡が設けられていて、前記ＣＷレーザ光の集光点が、該凹面反射鏡の焦点にある、
    ことを特徴とする請求項５に記載のレーザ駆動光源装置。     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 5.
  7. 　前記プラズマ容器が、凹面反射面を有する本体と、該本体の後方開口に設けられた入射窓と、該本体の前方開口に設けられた出射窓とからなり、前記本体と前記入射窓と前記出射窓によって密閉空間が形成されており、
    　前記ＣＷレーザ光の集光点が、前記本体の凹面反射面の焦点にある、
    ことを特徴とする請求項５に記載のレーザ駆動光源装置。     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 5.
  8. 　前記パルスレーザ源及び前記ＣＷレーザ源と、前記集光レンズとの間にダイクロイックミラーが配置され、
    　該ダイクロイックミラーはパルスレーザ光とＣＷレーザ光の一方を透過し、他方を反射するものである、
    ことを特徴とする請求項５～７のいずれかに記載のレーザ駆動光源装置。     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 5 to 7, wherein
  9. 　前記パルスレーザ源及び前記ＣＷレーザ源と、前記集光レンズとの間に配置されて、前記パルスレーザ光と前記ＣＷレーザ光の一方を透過し、他方を反射する第一のダイクロイックミラーと、
    　前記プラズマ容器の励起光出射側前方に配置されて、前記集光レンズを通過した前記パルスレーザ光及び前記ＣＷレーザ光を前記プラズマ容器に向けて反射し、前記プラズマ容器からの励起光を透過する第二のダイクロイックミラーと、
    を備えていることを特徴とする請求項５に記載のレーザ駆動光源装置。     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 5, comprising:
  10. 　前記パルスレーザ源と前記ＣＷレーザ源とにそれぞれ対応するファイバを有するファイバカプラを備え、
    　該ファイバカプラの合波ファイバを、アクロマティックレンズを介在させて前記集光レンズに対向させてなる、
    ことを特徴とする請求項５～７のいずれかに記載のレーザ駆動光源装置。
     
     
          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 5 to 7, wherein


PCT/JP2017/008457 2016-05-24 2017-03-03 Laser-driven light source device WO2017203791A1 (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP2016-103203 2016-05-24
JP2016103203A JP2017212061A (en) 2016-05-24 2016-05-24 Laser drive lamp
JP2017-018220 2017-02-03
JP2017018220A JP2018125227A (en) 2017-02-03 2017-02-03 Laser driving light source device

Publications (1)

Publication Number Publication Date
WO2017203791A1 true WO2017203791A1 (en) 2017-11-30

Family

ID=60411517

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2017/008457 WO2017203791A1 (en) 2016-05-24 2017-03-03 Laser-driven light source device

Country Status (1)

Country Link
WO (1) WO2017203791A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113690126A (en) * 2021-08-19 2021-11-23 华中科技大学 Laser-sustained plasma broadband light source and application
US20220200225A1 (en) * 2020-12-21 2022-06-23 Hamamatsu Photonics K.K Light emitting sealed body and light source device

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009532829A (en) * 2006-03-31 2009-09-10 エナジェティック・テクノロジー・インコーポレーテッド Laser-driven light source
JP2010170994A (en) * 2008-12-27 2010-08-05 Ushio Inc Light source device
JP2011035039A (en) * 2009-07-30 2011-02-17 Ushio Inc Light source device
US20150049778A1 (en) * 2013-08-14 2015-02-19 Kla-Tencor Corporation System and Method for Separation of Pump Light and Collected Light in a Laser Pumped Light Source

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009532829A (en) * 2006-03-31 2009-09-10 エナジェティック・テクノロジー・インコーポレーテッド Laser-driven light source
JP2010170994A (en) * 2008-12-27 2010-08-05 Ushio Inc Light source device
JP2011035039A (en) * 2009-07-30 2011-02-17 Ushio Inc Light source device
US20150049778A1 (en) * 2013-08-14 2015-02-19 Kla-Tencor Corporation System and Method for Separation of Pump Light and Collected Light in a Laser Pumped Light Source

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20220200225A1 (en) * 2020-12-21 2022-06-23 Hamamatsu Photonics K.K Light emitting sealed body and light source device
US11862922B2 (en) * 2020-12-21 2024-01-02 Energetiq Technology, Inc. Light emitting sealed body and light source device
CN113690126A (en) * 2021-08-19 2021-11-23 华中科技大学 Laser-sustained plasma broadband light source and application

Similar Documents

Publication Publication Date Title
US9941655B2 (en) High power broadband light source
CN108140538B (en) Lighting source for electrodeless plasma ignition and plasma broadband source
CN102043346B (en) Light source apparatus
JP5557487B2 (en) Light source device
US9723703B2 (en) System and method for transverse pumping of laser-sustained plasma
JP2018531487A6 (en) System and method for electrodeless plasma ignition in a laser sustained plasma light source
JP2020155418A (en) System for separation of pump light and collected light in laser pumped light source
US20150262808A1 (en) Light Source Driven by Laser
WO2017203791A1 (en) Laser-driven light source device
CN108353490B (en) System and method for laser sustained plasma illumination
CN108369891B (en) Laser sustained plasma light source with graded absorption characteristics
JP2018125227A (en) Laser driving light source device
JP2018060640A (en) Laser-driven light source
JP5661169B2 (en) Light source device
JP2017212061A (en) Laser drive lamp
JP2017216125A (en) Laser driven lamp
JP6390863B2 (en) Laser drive light source device
KR20220133979A (en) Laser Pumped Plasma Light Source and Plasma Ignition Method

Legal Events

Date Code Title Description
NENP Non-entry into the national phase

Ref country code: DE

121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 17802393

Country of ref document: EP

Kind code of ref document: A1

122 Ep: pct application non-entry in european phase

Ref document number: 17802393

Country of ref document: EP

Kind code of ref document: A1