JP2005333065A - Solid state laser apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid state laser apparatus radiating laser beams of a plurality of wavelengths, maintaining low-cost and high-accuracy characteristics and improving radiation efficiency of laser beams. <P>SOLUTION: The solid state laser apparatus is provided with: a first optical resonator having a first optical axis 24; a second optical resonator having a second optical axis; a third optical resonator having a third optical axis 30; an optical path switching means 37 formed on an intersecting part between the second optical axis 32 and the third optical axis 30; a first wavelength transforming optical member 28 arranged on the first optical axis 24 and the second optical axis 32; and a second wavelength transforming optical member 38 arranged on the third optical axis 30 passing the optical path switching means 28. In the solid state laser apparatus, a laser beam of sum frequency is radiated by the first wavelength transforming optical member in a state of transmitting a second basic wave oscillated from the second optical resonator, and in a state of the optical path switching means transmitting a first basic wave oscillated from the first optical resonator, a laser beam of secondary higher harmonic is projected by a third basic wave oscillated from the third optical resonator and the second wavelength transforming optical member 38. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a solid-state laser device capable of emitting laser beams having a plurality of wavelengths.

  In recent years, the use of laser beams in the field of medical treatment has become widespread. For example, there is a medical laser surgical apparatus that irradiates a diseased part with a laser beam and treats it.

  A medical machine using a laser beam performs non-contact photocoagulation, removal, incision, etc. of a treatment site in a non-contact manner, and the color, ie, wavelength, of the laser beam used differs depending on the type of treatment. In a laser apparatus which is a light emission source, it is desired to supply laser beams having a plurality of wavelengths to a medical machine.

  As a conventional laser apparatus capable of emitting laser beams having a plurality of wavelengths, there is one disclosed in Patent Document 1.

  This will be described with reference to FIG.

  In FIG. 4, 1 is a laser oscillator, 2 is a control unit, and 3 is an operation unit. The control unit 2 controls the wavelength of the laser beam emitted from the laser oscillator 1 and controls the intensity of the laser beam. The operation unit 3 is provided with a switch for selecting a wavelength and various switches for setting and inputting a laser beam irradiation condition.

  The laser oscillator 1 has a semiconductor laser 4 as an excitation light source, and a laser beam emitted from the semiconductor laser 4 is guided to a first resonance unit 5, a second resonance unit 6, and a third resonance unit 7. Yes.

  The first resonating unit 5 is provided on a first reflecting mirror 9, a laser crystal 11, an output mirror 12 that is a semi-transmissive mirror, and a reflected optical axis 13 of the output mirror 12 disposed on the first optical axis 8 a. The first wavelength converting optical member (nonlinear crystal) 14a and the second reflecting mirror 15a.

  The second resonating unit 6 has a second optical axis 8b, and the second resonating unit reflecting mirror 16 is provided on the second optical axis 8b so as to be movable on the second optical axis 8b. The second wavelength converting optical member (nonlinear crystal) 14b and the third reflecting mirror 15b provided on the two optical axes 8b are provided. The second resonating part reflecting mirror 16 is provided by the second resonating part driving part 17. It is moved and positioned at the intersection of the reflected optical axis 13 and the second optical axis 8b.

  The third resonating unit 7 has a third optical axis 8c, and the third resonating mirror 18 for the third resonating unit provided on the third optical axis 8c so as to be movable on the third optical axis 8c. A third wavelength converting optical member (nonlinear crystal) 14c and a fourth reflecting mirror 15c provided on the three optical axes 8c are provided. The third resonating part reflecting mirror 18 is provided by a third resonating part driving part 19. It is moved and positioned at the intersection of the reflection optical axis 13 and the third optical axis 8c.

  In the laser apparatus, when the laser beam having the first wavelength is emitted, the second resonating part reflecting mirror 16 and the third resonating part reflecting mirror 18 are moved backward from the reflected optical axis 13. The laser beam incident on the first resonating unit 5 is amplified between the first reflecting mirror 9 and the second reflecting mirror 15a, passes through the output mirror 12, and is emitted.

  When the laser beam having the second wavelength is emitted, the second resonating part reflecting mirror 16 is moved to the intersection of the reflecting optical axis 13 and the second optical axis 8b, and the first reflecting mirror is moved. 9 and the third reflecting mirror 15b, the second resonating unit 6 amplifies the laser beam and emits it through the output mirror 12.

  When a laser beam having a third wavelength is emitted, the second resonator reflecting mirror 16 is retracted from the reflecting optical axis 13 and the third resonator reflecting mirror 18 is moved to the reflecting optical axis 13. And the third optical axis 8c, the laser beam is amplified by the third resonating unit 7 formed between the first reflecting mirror 9 and the fourth reflecting mirror 15c, and the output mirror 12 is It is injected through.

  Thus, by selecting the positions of the second resonance part reflection mirror 16 and the third resonance part reflection mirror 18, laser beams having a plurality of wavelengths can be emitted.

  In the above-described conventional laser device, the second resonator reflection mirror 16 and the third resonator reflection mirror 18 are configured to move, so that the drive unit, the second resonator reflection mirror 16, and the A guide mechanism for the three-resonator reflecting mirror 18 is required, and the mechanism is complicated. In addition, since the stop positions of the second resonator reflector 16 and the third resonator reflector 18 greatly affect the laser beam emission efficiency, high accuracy is required.

  For this reason, a guide mechanism, a control system, and the like that require high accuracy are required, and there is a problem that manufacturing costs are increased.

JP 2002-151774 A

  In view of such circumstances, the present invention provides a solid-state laser device capable of emitting laser beams of a plurality of wavelengths, maintaining high accuracy at low cost, and improving the emission efficiency.

  The present invention includes a first optical resonator having a first optical axis, a second optical resonator having a second optical axis, a third optical resonator having a third optical axis, An optical path switching means provided at an intersection of the second optical axis and the third optical axis, the first optical axis and the second light; A first wavelength converting optical member disposed on an axis, and a second wavelength converting optical member disposed on the third optical axis passing through the optical path switching means, wherein the first optical axis is The third optical axis is refracted by the optical path switching means so as to be parallel to the second optical axis, and the optical path switching means is a first basic that is oscillated by the first optical resonator. Reflecting or transmitting a wave and transmitting a second fundamental wave oscillated by the second optical resonator, and the optical path switching means is a first oscillating by the first optical resonator. A sum frequency laser beam is emitted by the first wavelength converting optical member while reflecting the main wave and transmitting the second fundamental wave oscillated by the second optical resonator, and the optical path switching means A second harmonic laser beam is generated from the third fundamental wave oscillated by the third optical resonator and the second wavelength converting optical member in a state where the first fundamental wave oscillated by the first optical resonator is transmitted. The optical path switching means relates to an optical member that reflects either one of the first fundamental wave and the second fundamental wave and transmits either one of the fundamental wave and the fundamental wave. The present invention relates to a solid-state laser device that has a transmission part that transmits light, and alternatively positions the optical member and the transmission part at the intersection, and the first fundamental wave and the second fundamental wave have different polarization directions. The optical member is a polarization beam splitter. The dependency, and the optical member relates to a solid-state laser apparatus is a dichroic mirror, further or the optical member, the transmission portion are those of the solid-state laser device provided in the rotary plate rotatable.

  According to the present invention, a first optical resonator having a first optical axis, a second optical resonator having a second optical axis, a third optical resonator having a third optical axis, , The second optical axis and the third optical axis intersect, an optical path switching means provided at the intersection of the second optical axis and the third optical axis, the first optical axis and the second optical axis. And a first wavelength converting optical member disposed on the third optical axis passing through the optical path switching means, and the first light The axis is refracted by the optical path switching means so that the third optical axis is parallel to the second optical axis, and the optical path switching means is oscillated by the first optical resonator. One fundamental wave is reflected or transmitted, and the second fundamental wave oscillated by the second optical resonator is transmitted, and the optical path switching means oscillates the first optical resonator. A sum frequency laser beam is emitted by the first wavelength conversion optical member in a state of reflecting the first fundamental wave and transmitting the second fundamental wave oscillated by the second optical resonator, and the optical path switching means A second harmonic laser from the third fundamental wave oscillated by the third optical resonator and the second wavelength converting optical member in a state where the first fundamental wave oscillated by the first optical resonator is transmitted. Since the light beam is emitted, it is possible to emit laser beams of multiple wavelengths, the structure is simple, there are few moving parts when the emitted wavelength is polarized, and the high accuracy is maintained at low cost. It exhibits an excellent effect that the efficiency can be improved.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  In FIG. 1, 21 is a first laser light source section, 22 is a second laser light source section, 23 is a third laser light source section, 55 is a first optical resonator, 56 is a second optical resonator, and 57 is a third optical resonance. Shows the vessel.

  The first laser light source unit 21 has a first optical axis 24, and a first condenser lens unit 25, a first concave mirror 26, and a first solid-state laser medium (first laser crystal) 27 on the first optical axis 24. , An optical path switching means 37 (described later) is disposed, and the first optical axis 24 is refracted by the optical path switching means 37 and is refracted by the refracted portion of the first optical axis 24 (hereinafter referred to as the first optical axis 24 '). A first nonlinear optical medium (first wavelength converting optical member (NLO)) 28 and a first output mirror 29 are disposed.

  A first LD light emitting device (semiconductor laser: Laser Diode) 31 is disposed opposite to the first light collecting lens unit 25, and excitation light emitted from the first LD light emitting device 31 is transmitted to the first light collecting lens unit. 25, passes through the first concave mirror 26, and is focused on the first laser crystal 27 by the first condenser lens unit 25. The first LD light emitter 31 may be a single semiconductor laser or a plurality of semiconductor lasers.

  The polarization direction of the laser beam emitted from the first LD light emitter 31 and oscillated between the first concave mirror 26 and the first output mirror 29 is, for example, that the crystal direction of the first laser crystal 27 is S-polarized light. Is set.

  The optical path switching means 37 includes a rotating plate 51 that is rotatably provided. The rotating plate 51 has an optical member such as a polarizing beam splitter 52 and a transmission hole 53 that does not optically block the first optical axis 24. The rotation plate 54 of the rotation plate 51 is inclined with respect to the first optical axis 24, and the rotation plate 51 is rotated by a rotation means such as a motor or a solenoid (not shown) so that the first rotation position and the first rotation position. 2 can be positioned at the rotational position. The polarizing beam splitter 52 is positioned on the first optical axis 24 at the first rotational position, and the transmission hole 53 is positioned on the first optical axis 24 at the second rotational position. .

  The polarization beam splitter 52 has a 90 ° polarization direction different from the polarization direction s of the laser beam (first fundamental wave) oscillated between the first concave mirror 26 and the first output mirror 29. Accordingly, the polarization beam splitter 52 reflects S-polarized light and transmits P-polarized light.

  Dielectric reflecting films are formed on the reflecting surface of the first concave mirror 26 and the reflecting surface of the first output mirror 29, respectively. The first laser crystal 27 is a solid-state laser element for excitation. When the wavelength of the first LD emitter 31 is 809 nm, for example, when Nd: YVO4 is used, the first laser crystal 27 oscillates at a wavelength of 1064 nm. In addition, YAG (yttrium aluminum garnet) doped with Nd3 + ions or the like is employed, and YAG has oscillation lines of 946 nm, 1064 nm, 1319 nm, and the like. Further, Ti (Sapphire) having an oscillation line of 700 to 900 nm can be used.

  The first wavelength conversion optical member 28 is a sum frequency wavelength conversion optical member, and a dielectric reflection film 58 is formed on the polarizing reflection plate 37 side. As the first wavelength converting optical member 28, KTP (KTiOPO4 potassium titanyl phosphate) is used. As the first wavelength converting optical member 28, in addition to KTP, BBO (β-BaB 2 O 4 β-type barium borate), LBO (LiB 3 O 5 lithium triborate), KNbO 3 (potassium niobate), etc. are also employed. The

  The dielectric reflecting film of the first concave mirror 26 is highly transmissive with respect to the excitation light from the first LD light emitter 31, for example, 809 nm excitation light, and the oscillation wavelength (the first wavelength emitted by the first laser crystal 27) Fundamental wave), for example, a high reflection with respect to the first fundamental wave of 1064 nm.

  The dielectric reflecting film of the first output mirror 29 is highly reflective with respect to the first fundamental wave and the second fundamental wave of the oscillation wavelength emitted by the second laser crystal 36, and the first wavelength converting optical member 28. Is highly transparent to the sum frequency (SFG: SUM FREQUENCY GENERATION) of the first fundamental wave and the second fundamental wave. For example, the first fundamental wave of 1064 nm and the second fundamental wave of 1342 nm are highly reflective, and the first frequency of 593 nm (orange laser beam) is highly transmissive.

  The dielectric reflection film 58 of the first wavelength converting optical member 28 is highly transmissive with respect to the first fundamental wave and the second fundamental wave, and highly reflective at the sum frequency.

  In the first laser light source unit 21, the first concave mirror 26, the first output mirror 29, and the first laser crystal 27 constitute a first optical resonator 55, and the laser beam from the first LD light emitter 31 is emitted. When the first laser crystal 27 is pumped through the first condenser lens unit 25, the laser beam is reciprocated between the first concave mirror 26 and the first output mirror 29 so as to be S-polarized. The first fundamental wave oscillates.

  Similarly, in the second laser light source unit 22, the second concave mirror 35, the first output mirror 29, and the second laser crystal 36 constitute a second optical resonator 56, and the laser beam from the second LD light emitter 33 is emitted. When the first laser crystal 36 is pumped through the second condenser lens unit 34, the laser beam is defined to reciprocate between the second concave mirror 35 and the first output mirror 29 to become P-polarized light. The second fundamental wave oscillates. As the second fundamental wave, for example, when the excitation light from the second LD light emitter 33 is 809 nm, the second fundamental wave is 1342 nm.

  A second wavelength converting optical member 38 and a second output mirror 39 are provided at a portion of the third optical axis 30 passing through the optical path switching means 37 that shares a part with the first optical axis 24 and passes through the optical path switching means 37. It is arranged. The third optical resonator 57 is constituted by the first concave mirror 26, the second output mirror 39, and the second wavelength converting optical member 38, and the third fundamental wave is oscillated. The second wavelength converting optical member 38 is made of, for example, SHG-KTP that converts a third fundamental wave having a wavelength of 1064 nm into a second harmonic wave (green laser beam) having a wavelength of 532 nm.

  The second output mirror 39 is formed with a dielectric reflection film, and is highly reflective to the third fundamental wave and highly transmissive to the second harmonic. A dielectric reflection film 59 is formed on the polarizing reflection plate 37 side of the second wavelength converting optical member 38. The dielectric reflection film 59 is highly transmissive with respect to the third fundamental wave, and the second harmonic wave. Is highly reflective.

  The second laser light source unit 22 has a second optical axis 32, and the second optical axis 32 intersects the third optical axis 30 at, for example, 90 ° at the position of the optical path switching means 37, and the second light The second LD light emitter 33, the second condenser lens unit 34, the second concave mirror 35, and the second laser crystal 36 are disposed on the shaft 32, and the portion of the second optical axis 32 that passes through the optical path switching means 37 Is shared with the first optical axis 24 ′, and the first wavelength converting optical member 28 and the first output mirror 29 are also shared with the first laser light source unit 21.

  The excitation light emitted from the second LD light emitter 33 is P-polarized light, is incident on the second condenser lens unit 34, passes through the second concave mirror 35, and is transmitted by the second condenser lens unit 34. Focused on the second laser crystal 36.

  The second laser crystal 36 is made of YAG (yttrium aluminum garnet) doped with Nd: YVO4, Nd3 + ions, Ti (Sapphire) or the like, and the second wavelength conversion optical member 38 is KTP (KTiOPO4 phosphoric acid). Titanyl potassium), BBO (β-BaB 2 O 4 β-type barium borate), LBO (LiB 3 O 5 lithium triborate), KNbO 3 (potassium niobate) and the like are employed.

  The third laser light source unit 23 has a fourth optical axis 42, and a third LD light emitter 43, a third condenser lens unit 44, and a reflecting mirror 45 are disposed on the fourth optical axis 42, and the third LD The light emitter 43 emits a red laser beam. The fourth optical axis 42 is deflected to the fourth optical axis 42 ′ by the reflecting mirror 45.

  The third optical axis 30 that passes through the second output mirror 39 is deflected by the reflecting mirror 41 and intersects the fourth optical axis 42 ', and at the intersection of the third optical axis 30 and the fourth optical axis 42'. The first dichroic mirror 46 is disposed. The first optical axis 24 'and the fourth optical axis 42' intersect each other, and a second dichroic mirror 47 is disposed at the intersection of the first optical axis 24 'and the fourth optical axis 42'. .

  The first dichroic mirror 46 transmits a laser beam emitted from the third LD emitter 43, for example, a red laser beam, and reflects a laser beam having a wavelength other than the red laser beam. The second dichroic mirror 47 reflects the sum frequency from the first optical axis 24 ′, for example, orange (593 nm) wavelength, and transmits other wavelengths.

  Further, the first LD light emitter 31 and the second LD in the state where the optical path switching unit 37 positions the rotating plate 51 in the first rotation position, that is, the polarization beam splitter 52 is positioned on the first optical axis 24. When the light emitter 33 is simultaneously driven to emit excitation light from both the first LD light emitter 31 and the second LD light emitter 33, the S-polarized light beam from the first LD light emitter 31 is reflected by the polarization beam splitter 52, The P-polarized light beam from the second LD light emitter 33 passes through the polarization beam splitter 52.

  Thus, a second fundamental wave is oscillated between the second concave mirror 35 and the first output mirror 29 by the laser beam from the second LD emitter 33, and the second fundamental wave is oscillated by the laser beam from the first LD emitter 31. A first fundamental wave is oscillated between one concave mirror 26 and the first output mirror 29, and a sum frequency (SFG) of the first fundamental wave and the second fundamental wave is emitted from the first output mirror 29. The sum frequency color is, for example, orange having a wavelength of 593 nm.

  Note that the solid-state laser device includes a power supply control unit 49 that drives and controls the driving state of the first LD light emitter 31, the second LD light emitter 33, and the third LD light emitter 43. The 1LD light emitter 31, the second LD light emitter 33, and the third LD light emitter 43 can be controlled in various modes, such as being able to blink independently or controlling the light intensity in synchronization.

  The operation will be described below with reference to FIGS.

  When the first LD light emitter 31 and the second LD light emitter 33 are turned off and the third LD light emitter 43 is turned on, the red laser beam is reflected by the reflecting mirror 45, and the first dichroic mirror 46 and the second dichroic light are reflected. It passes through the mirror 47. Therefore, a red laser beam is emitted from the solid-state laser device.

  As shown in FIG. 2, the third LD light emitter 43 is turned off, the rotating plate 51 is set to the first rotation position, and the polarization beam splitter 52 is positioned on the first optical axis 24. When the first LD light emitter 31 and the second LD light emitter 33 are turned on, the first fundamental wave defined so that the first optical resonator 55 becomes S-polarized light by the excitation light of the first LD light emitter 31 is emitted. Oscillates and is reflected by the polarization beam splitter 52. The second optical resonator 56 oscillates a second fundamental wave defined to be P-polarized light by the excitation light of the second LD light emitter 33 and passes through the polarization beam splitter 52.

  The first fundamental wave and the second fundamental wave are converted into a sum frequency laser beam by the first wavelength converting optical member 28, and a sum frequency, for example, an orange laser beam is transmitted through the first output mirror 29 and emitted. Reflected by the dichroic mirror 47, an orange laser beam is emitted from the solid-state laser device.

  Next, as shown in FIG. 3, the rotating plate 51 is rotated to the second rotation position, and the transmission hole 53 is positioned on the first optical axis 24. When the first LD light emitter 31 is turned on, and the second LD light emitter 33 and the third LD light emitter 43 are turned off, the laser beam from the first LD light emitter 31 is transmitted through the transmission hole 53 and the first concave mirror. 26 and the second output mirror 39, a third fundamental wave is oscillated, and further, for example, a green laser beam is oscillated by the second wavelength converting optical member 38, and the green laser beam is emitted from the second output mirror 39. The The green laser beam is reflected by the reflecting mirror 41 and the first dichroic mirror 46, passes through the second dichroic mirror 47, and the green laser beam is emitted from the solid-state laser device.

  Thus, the power supply control unit 49 controls the blinking of the first LD light emitter 31, the second LD light emitter 33, and the third LD light emitter 43, and the rotational position control of the rotating plate 51, so that the red color is emitted from the solid-state laser device. It is possible to emit laser beams of three colors, orange and green. Further, since the position of the optical path switching means 37 is changed by rotation, the mechanism is simple.

  The polarizing beam splitter 52 may be changed to a dichroic mirror 52 ′. In this case, for example, the dichroic mirror 52 ′ reflects the first fundamental wave (1064 nm wavelength) oscillated by the first optical resonator 55 and the second fundamental wave (1342 nm) oscillated by the second optical resonator 56. (Wavelength).

  In this case as well, the sum frequency is generated with the dichroic mirror 52 ′ positioned on the first optical axis 24 as described above, and the orange laser beam is emitted from the first output mirror 29 and transmitted. A green laser beam is emitted in a state where the hole 53 is positioned on the first optical axis 24.

  In the above description, the polarization beam splitter 52 and the transmission hole 53 are provided in the rotating plate 51, but they may be provided in a slide plate that goes in and out with respect to the first optical axis 24. The slide plate simply inserts and removes the polarizing beam splitter 52 with respect to the first laser light source unit 21. When the polarizing beam splitter 52 is not positioned on the first optical axis 24, the first optical axis is used. The transmission part which is the space which does not obstruct | occlude 24 may be formed.

  It goes without saying that laser beams of various colors can be emitted by appropriately selecting a laser crystal and a wavelength converting optical member.

It is a schematic block diagram which shows embodiment of this invention. It is explanatory drawing which shows the effect | action of embodiment of this invention. It is explanatory drawing which shows the effect | action of embodiment of this invention. It is a schematic block diagram of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 21 1st laser light source part 22 2nd laser light source part 23 3rd laser light source part 24 1st optical axis 26 1st concave mirror 27 1st laser crystal 28 1st wavelength conversion optical member 29 1st output mirror 31 1st LD light emitter 32 2nd optical axis 33 2nd LD light emitter 35 2nd concave mirror 36 2nd laser crystal 37 Optical path switching means 38 2nd wavelength conversion optical member 39 2nd output mirror 43 3rd LD light emitter 49 Power supply control part 51 Rotating plate 52 Polarization Beam splitter 53 Transmission hole

Claims (5)

  A first optical resonator having a first optical axis; a second optical resonator having a second optical axis; a third optical resonator having a third optical axis; and the second light. And the optical path switching means provided at the intersection of the second optical axis and the third optical axis, and the first optical axis and the second optical axis. A first wavelength converting optical member, and a second wavelength converting optical member disposed on the third optical axis passing through the optical path switching means, wherein the first optical axis is the third optical axis. The optical path is refracted by the optical path switching means so as to be parallel to the second optical axis, and the optical path switching means reflects the first fundamental wave oscillated by the first optical resonator, Alternatively, it transmits the second fundamental wave that is transmitted and oscillated by the second optical resonator, and the optical path switching means counteracts the first fundamental wave that is oscillated by the first optical resonator. Then, a sum frequency laser beam is emitted by the first wavelength converting optical member in a state where the second fundamental wave oscillated by the second optical resonator is transmitted, and the optical path switching means is the first optical resonance. A second harmonic laser beam is emitted from the third fundamental wave oscillated by the third optical resonator and the second wavelength converting optical member in a state where the first fundamental wave oscillated by the resonator is transmitted. A solid-state laser device characterized by the above.   The optical path switching means includes an optical member that reflects one of the first fundamental wave and the second fundamental wave and transmits the other, and a transmission portion that transmits the one of the fundamental waves. The solid-state laser device according to claim 1, wherein a member and the transmission portion are alternatively positioned at the intersecting portion.   3. The solid-state laser device according to claim 2, wherein the first fundamental wave and the second fundamental wave have different polarization directions, and the optical member is a polarization beam splitter.   The solid-state laser device according to claim 2, wherein the optical member is a dichroic mirror.   The solid-state laser device according to claim 2, wherein the optical member and the transmission portion are provided on a rotatable rotating plate.

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