JP2010098215A - Solid-state laser rod and method of manufacturing the same, and solid-state laser device using the solid-state laser rod - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem wherein when a sand surface for pumping light convergence is formed on the outer peripheral surface of a laser base material, a formed assembly of laser base materials loses parallelism between the laser base materials, resulting in loss of parallelism, between both end surfaces of the laser base materials and the perpendicularity between the length direction and end surfaces of the laser base materials so that manufacture of a solid-state laser rod is poor in yield. <P>SOLUTION: The solid-state laser rod is of a columnar shape and has a side surface finished into a rough surface, while having parts of the side surface nearby both ends become mirror-finish planes, projected from the side surface. Both the end surfaces of the rod are polished into mirror-finish planes, and the parallelism between both the end surfaces is ≤1 minute. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a solid-state laser rod, a manufacturing method thereof, and a solid-state laser device using the solid-state laser rod.

  In recent years, lasers are rapidly and widely used in fields such as processing, medicine, and measurement. These laser types include solid lasers, gas lasers, fiber lasers, free electron lasers, and the like. Laser oscillation modes include continuous wave (CW), pulse mode, and the like, and the pulse width, wavelength, etc. can be set arbitrarily.

  Among these, the solid-state laser will be described. The solid-state laser is a device that takes out laser light by irradiating a solid-state laser rod provided in the laser unit with excitation light. It was the beginning of the solid-state laser that Mayman first oscillated with a ruby laser.

  In addition, a solid-state laser using YAG, which is an acronym of yttrium, aluminum, or garnet, as a rod base material is well known (for example, see Patent Document 1).

  A simple configuration of a conventional solid-state laser unit 1 is shown in FIG. The solid-state laser unit 1 basically includes a laser rod 3 that oscillates laser light, a reflecting mirror 4 and a reflecting mirror 5 that amplify the oscillated laser light, and a flash that irradiates the laser rod 3 with light energy. The lamp 6 includes a power source 8 for causing the flash lamp 6 to emit light, and a lens barrel 2 that covers the entire flash lamp 6, reflects light, and irradiates the laser rod 3.

  A reflective film may be formed on the end face of the laser rod 3 instead of the reflective mirror 4 and the reflective mirror 5. The reflective film is a dielectric multilayer film or the like, and is formed by a method such as sputtering. The reflectance of the reflecting mirror 5 is set to 80% to 95%, and the reflectance of the reflecting mirror 4 is set to almost total reflection of 99.5% or more, so that the laser can be amplified. Further, the laser beam emitted from the laser rod 3 is used by increasing the intensity by focusing it to one point with the lens 7 arranged on the emission axis of the laser rod 3.

  The parallelism of both end faces of such a laser rod is 5 seconds (5/3600 degrees) or less, and the perpendicularity between the side faces and the end faces is 5 minutes (5/60 degrees). Also, since the surface roughness of the side surface is about # 150 sand, the rods are overlapped and integrated with wax, and the parallelism is checked while polishing both ends, but the processing accuracy does not come out well There was a problem.

  Next, a method for manufacturing the laser rod 63 will be described. As shown in FIG. 12, first, in a first step 65, a plurality of quadrangular prism-shaped laser rods 62b are cut out from a plate-like base material 62a with a dicer or the like. Then, in the next second step 66, the cut-out quadrangular columnar laser rod 62b is processed into a columnar laser rod 62 by coreless grinding or cylindrical grinding. At this time, a sand surface (surface roughness Ra1-2) having a surface roughness of about # 150 is formed on the outer peripheral surface. Next, in the third step 67, a plurality of laser rods 62 are collected and bonded with wax or the like to form an aggregate, but an aggregate 62c assembled with the laser rods 62 and an aggregate assembled via a middle jig. There is a body 62d. Both end surfaces of the aggregate 62c or 62d are mirror-polished to obtain the parallelism of both end surfaces and the perpendicularity between the both end surfaces and the longitudinal direction of the laser rod 62. Next, although not shown, in the fourth step 68, a reflection film is formed on both end faces.

As prior art document information related to the invention of this application, for example, Patent Document 1 is known.
JP-A-7-115237

  The parallelism of both end faces of such a laser rod is 5 seconds (5/3600 degrees) or less, and the perpendicularity between the side faces and the end faces is 5 minutes (5/60 degrees). Since the surface roughness of the side surface of the rod is Ra1-2, when the rods are overlapped with each other and integrated with wax to confirm the parallelism while polishing both end faces, There was a problem that the processing accuracy was not good. Therefore, it has been difficult to obtain a solid laser rod with a high yield.

  The present invention solves such a problem, and an object of the present invention is to provide a solid laser rod having a high yield.

  In order to achieve this object, the solid laser rod according to the present invention includes a side surface finished with a rough surface, a mirror surface having a diameter larger than the side surface at a portion near both ends of the side surface, and both end surfaces subjected to mirror polishing. As a result, the parallelism of both end faces is set to 1 minute or less, whereby the intended purpose can be achieved.

  As described above, according to the present invention, the rod is a cylindrical laser oscillation rod, and the rod has a rough side surface and a part near both ends of the side surface so as to have a larger diameter than the side surface. A solid laser rod having a mirror surface, mirror-polished both end surfaces, and parallelism of both end surfaces is 1 minute or less.

  Therefore, an assembly in which the solid laser rods are arranged in parallel can be easily obtained without being affected by the rough surface formed on the side surface of the solid laser rod. Therefore, when reflecting films are formed on both end faces of the solid-state laser rod, a predetermined parallelism between both end faces and a perpendicularity between both end faces and the side face can be easily obtained, and the solid-state laser rod with good yield can be obtained. Can be obtained.

(Embodiment 1)
FIG. 1 is a perspective view of a solid-state laser rod 11 in the first embodiment. In this embodiment, Er: YAG (erbium-doped yttrium, aluminum, garnet) is used as the material of the solid-state laser rod 11. In FIG. 1, a side surface 12 has a cylindrical shape, and is formed of a sand surface (rough surface) having a mesh size of about # 150 (surface roughness Ra1 to 2) for the purpose of collecting excitation light. Convex reference surfaces 14a and 14b (first and second reference surfaces) are provided at both ends of the solid laser rod 11 with respect to the side surface 12 of the laser rod 11 rather than the side surface 13, respectively. The flatness of the reference surfaces 14a and 14b is an optical mirror surface of about λ / 10 with respect to the laser wavelength λ.
The flatness of the end faces 15a and 15b is mirror-finished with a roughness of about λ / 10 with respect to the laser wavelength λ. When an external resonator is used, the laser can be oscillated as it is. it can.

  When an external resonator is not used, a first reflective film 15a (partially transmissive reflective film) having a reflectance of 80 to 95% is formed on one end face 12a of the solid-state laser rod 11, and the other A second reflection film 15b (total reflection film) having a reflectance of 99.5% or more is formed on the end face 12b. The solid laser rod 11 has a diameter of approximately 2 mm and a length of 20 mm to 40 mm.

  Next, a method for manufacturing the solid laser rod 11 will be described. In the first step 16 shown in FIG. 2, the plate-like laser base material 21 is cut with a cutter such as a dicer to cut out a square prism-shaped laser prism 22. Next, in the second step 17, in order to form the reference surfaces 23a and 23b by processing the laser prism 22 into a columnar shape using centerless grinding or cylindrical grinding and further providing steps at both ends. Then, the cylindrical side surface 13a is processed by using, for example, coreless grinding or cylindrical grinding to obtain the laser cylinder 23. In addition, in order to provide a step at both ends, the reference surfaces 23a and 23b may be masked and the cylindrical side surface 13a may be formed by sandblasting. The surface roughness of the cylindrical shape 13a at this time forms a sand surface of about mesh # 150. The reference surfaces 23a and 23b are the bases of the reference surfaces 14a and 14b and have a diameter larger than the diameter of the columnar shape 13a.

Next, in the third step 18, the reference surfaces 23a and 23b are mirror-finished to form the reference surfaces 14a and 14b. This becomes the laser rod base material 12. The reference surfaces 14a and 14b are optical mirror surfaces having a flatness of about λ / 10, where λ is the wavelength of the reference light for optical measurement. (Here, λ is 630 nm because a red laser is used.)
Next, in the 4th process 19, the 1st aggregate 24a or the 2nd aggregate 24b which collected two or more laser rod base materials 12 is formed. The first aggregate 24a is formed by bundling only a plurality of laser rod base materials 12. When a plurality of laser rod base materials 12 are bundled, the cylindrical side surfaces 13a forming the sand surface are not in contact with each other, and only the reference surfaces 14a and 14b are in contact with each other. It is necessary to fix with wax etc. so as not to leave. Since the reference surfaces 14a and 14b are mirror-finished, the plurality of bundled laser rod base materials 12 are maintained in parallel even though the cylindrical side surface 13 is a sand surface.

  In the second assembly 24b, a plurality of laser rod base materials 12 are bundled and attached to the outer peripheral surface of the cylindrical member 25 whose outer peripheral surface is mirror-finished. Even if a plurality of laser rod base materials 12 are bundled and attached to the cylindrical member 25, in this embodiment, the outer peripheral surface 13a forming the sand surface does not contact the cylindrical member 25, and only the reference surfaces 14a and 14b are cylindrical members. 25 comes into contact. Since the reference surfaces 14a and 14b are mirror-finished, a plurality of laser rod base materials 12 mounted in parallel are maintained even though the main body 13 is a sand surface.

  The assembly 24a or assembly 24b configured as described above is placed on a fixing jig (not shown), placed on the rotating surface plate 26 for lapping, and a predetermined load (not shown) is applied. Then, while rotating the rotating platen 26, the fixed jig also rotates to polish one end surface 12a of the laser rod base material 12 to a mirror surface. At this time, an abrasive mixed with a liquid is injected. The particle size of the abrasive is reduced in several stages over time. After the polishing of one end is completed, the assembly 24a, 24b is turned upside down and the other end surface 12b is also polished to a mirror surface.

  As described above, since the parallelism between the plurality of laser rod base materials 12 is ensured by the reference surfaces 14a and 14b, the perpendicularity between the length direction of the laser rod base material 12 and the both end surfaces 12a and 12b (5 / 60 degrees) and the parallelism (5/3600 degrees) of the both end faces 12a and 12b of the laser rod base material 12 can be easily obtained and processed with a high yield.

  Next, the fifth step 20 will be described with reference to FIGS. The fifth step 20 is a step of forming the reflection films 15a and 15b on the both end faces 12a and 12b of the laser rod base material 12, respectively. In the fifth step 20, first, as shown in FIG. 3, a plurality of laser rod base materials 12 are set on the film forming jig 27. In the present embodiment, five laser rod base materials 12 are set in a row and three laser rod base materials 12 are set in a vertical row, and a total of 15 laser rod base materials 12 are set. Thus, the set film-forming jig 27 is put into a film-forming apparatus (here, IBS: ion beam sputtering) to form a film.

  On a normal laser film, a dielectric multilayer film of a system in which a material having a high refractive index and a material having a low refractive index are alternately formed with respect to a target laser wavelength to increase the reflectance is formed. The layer of the film is determined by the target laser wavelength. First, a reflective film having a reflectance of 80 to 95% is formed on one end face 12a as a first reflective film 15a (partially transmissive reflective film). Next, a reflective film having a reflectance of 99.5% or more is formed as the second reflective film 15b (total reflection film) also on the other end face 12b.

  FIG. 4 is a perspective view in which the first reflective film 15a is mounted on, for example, one end surface 12a of one laser rod base material 12. FIG. The diameter 28 is the diameter of the reference surface 14a (or the reference surface 14b). If the diameter end 29b is formed into a square with a right angle, the stress is concentrated and the film formation (the first reflective film 15a in FIG. 4) is easily peeled off. Therefore, as shown in FIG. By forming the C surface 31 to such a degree, the film is not easily peeled off, and the strength of the film formation can be maintained.

  Here, as shown in FIG. 8, the radial distance 29 and the laser output light 30 are the strongest at the diameter center 29a, the output at the diameter end 29b is very small, and the intensity used for finger puncture or the like. Is negligible. Therefore, even if the C surface 31 is formed, the characteristics of the laser output light 30 are hardly affected. Further, since the resonance of the laser is performed within the diameter of the cylindrical side surface 13a, even if the diameters of the reference surfaces 14a and 14b are made larger than the diameter of the cylindrical side surface 13a, the characteristics of the laser output light 30 are not affected.

  As shown in FIG. 6, the laser beam 32 in the laser rod base material 12 has a first reflecting film 15a formed on one end surface 12a of the laser rod base material 12, and the other of the laser rod base material 12. When the intensity of the laser beam 32 exceeds a certain level when amplified with repeated reflection with the second reflection film 15b formed on the end surface 12b of the solid state laser, the solid laser passes through the first reflection film 15a. Output to the outside of the rod 11. This is because the light output to the outside becomes the laser output light 30.

  Here, as shown in FIG. 7, in the large diameter portion 14c of the reference surfaces 14a and 14b having a diameter larger than that of the cylindrical side surface 13a, the amplification of the laser beam 32 does not occur. It depends.

  In addition, as shown in FIG. 9, the solid laser rod 11 is attached to the mounting member 33 using the reference surfaces 14a and 14b, but the reference surfaces 14a and 14b are mirror-finished. Mounting accuracy can be improved. In addition, with the amplification of the laser beam 32, it is conceivable that heat is generated and the laser rod base material 12 expands. However, even if the laser rod base material 12 expands, the supporting portion is mirror-finished. Since the laser rod base material 12 slides on the mounting member 33 because of the reference surfaces 14a and 14b, the laser rod base material 12 is less stressed because the elongation in the optical axis direction is performed without friction.

(Embodiment 2)
FIG. 10 is a cross-sectional view of a laser puncture device 41 using the solid-state laser rod 11 described in the first embodiment. The same components as those in the first embodiment are denoted by the same reference numerals, and the description is simplified.

  In FIG. 10, the inside of a cylindrical casing 42 having a circular or elliptical shape is a mirror surface 42a in order to efficiently reflect the light source. When the casing 42 is elliptical, a flash lamp (used as an example of a light source) 43 is disposed at one focal point, and the solid laser rod 11 is disposed at the other focal point. The emitted light is efficiently irradiated to the solid-state laser rod 11. In addition, since the reference surfaces 14a and 14b formed at both ends of the solid laser rod 11 are supported and fixed by the mounting member 33, the laser output does not decrease.

  A first reflective film 15a is formed on one end face 12a of the laser rod base material 12 constituting the solid laser rod 11, and a lens 44 is provided in front of the first reflective film 15a. A laser transmission plate 42b through which the laser output light 30 is transmitted is attached to the casing 42 so that the lens 44 is not contaminated by dust from the outside further in front of the lens 44. A second reflective film 15 b is formed on the other end surface 12 b of the laser rod base material 12.

  When a voltage of about 200 V to 700 V is applied to both ends of the flash lamp 43 by the power source 51 and then a voltage of about 5 to 10 kV is momentarily applied as a trigger voltage, the spark coil is boosted, and the enclosed xenon gas is generated. It is ionized, electricity flows and xenon gas is discharged to emit light. This becomes excitation light.

  The excitation light emitted from the flash lamp 43 enters the solid laser rod 11 and excites a doped laser operating material (in this example, erbium Er) to generate light. This is stimulated emission.

  The generated light resonates and is amplified between the first reflective film 15a, the solid laser rod 11, and the second reflective film 15b. Part of the amplified laser light passes through the reflective film 15a. The laser light that has passed through the reflection film 15a is transmitted through the lens 44 and emitted, and then passes through the laser transmission plate 42b and is condensed.

  When the puncture finger 47 is placed on the portion of the light collected in this manner, the skin 47 a can be punctured by the laser output light 30. A portion of the skin 47a is transpirated by the laser output light 30, and blood 48 exudes from the capillaries inside the skin that are damaged at the same time. The exuded blood 48 can be used for blood tests such as a blood sugar level test and a cholesterol test.

  The solid laser rod according to the present invention is useful as a solid laser rod used in a laser puncture apparatus because of its good yield during production.

The perspective view of the solid-state laser rod in Embodiment 1 of this invention Same as above, manufacturing process diagram of laser base material Same perspective view of film formation process Same part perspective view Same as above, enlarged perspective view Same as above, explaining the operation of laser light Same perspective view of solid laser rod Same as above, characteristics of laser output Same perspective view of solid laser rod mounting explanation The block diagram of the laser puncture apparatus in Embodiment 2 same as the above Sectional view of a conventional laser unit Same as above, manufacturing process diagram of laser base material

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,11 Solid-state laser unit 2 Lens barrel 3 Laser rod 4, 5 Reflector 6 Flash lamp 7 Lens 8 Power supply 12 Laser rod base material 13 Side surface 13a Cylindrical side surface 14a, 14b Reference surface 15a, 15b End surface 21 Laser base material 22 Laser prism 23a, 23b Reference surface 23 Laser column 24a First assembly 24b Second assembly 25 Cylindrical member 27 Deposition jig 28 Diameter 29 Distance 29a Diameter center 29b Diameter end 30 Laser output light 31 C surface 32 Laser light 33 attachment member 41 laser puncture device 42 case 42a mirror surface 42b laser transmission plate 43 flash lamp 44 lens 47 puncture finger 47a skin 48 blood 62, 63 laser rod

Claims (9)

A rod for lasing in a cylindrical shape, wherein the side surface of the rod has a large mirror surface in the vicinity of both end portions thereof, and other than both end portions are formed as rough surfaces, and both end surfaces of the rod are mirror surfaces. A solid-state laser rod that is polished and has parallelism of both end faces of 1 minute or less. The solid laser rod according to claim 1, wherein both end faces are C-plane cut. 2. The solid laser rod according to claim 1, wherein a reflection film for a laser oscillation wavelength is formed on both end faces, one is a reflection film of 99.5% or more, and the other is a reflection film of 85% to 95%. The solid laser rod according to claim 1, wherein the rough surface of the rod is a sand surface of mesh # 150. 2. The solid laser rod according to claim 1, wherein the mirror surface of the solid laser rod is an optical mirror surface of about λ / 10 of a laser wavelength used for laser oscillation. A step of cutting a rod from a plate-shaped base material into a quadrangular prism shape, a step of forming a rod from the rod into a cylindrical shape, and a step that leaves a portion near both ends of the cylindrical rod as reference surfaces Forming a shape, forming the reference surface into a mirror surface, and forming an assembly in which only the reference surfaces of the plurality of rods on which the reference surface is formed are in contact with each other. A method for producing a solid-state laser rod, comprising a step of mirror-finishing and a step of forming a reflective film on each of both end faces. A step of cutting a rod into a square prism shape from a plate-shaped base material, a step of forming a rod from the rod into a cylindrical shape, and a step that leaves a portion near both ends of the cylindrical rod as a reference plane Forming a shape, forming the reference surface into a mirror surface, and forming an assembly in which only the reference surfaces of the plurality of rods on which the reference surface is formed are in contact with each other. A method for producing a solid laser rod, comprising a step of mirror finishing. A cylindrical body having an inner surface as a mirror surface, the solid laser rod according to claim 1 disposed in the cylindrical body, a light source disposed in parallel with the solid laser rod, and an axis of the solid laser rod. And a solid-state laser device. The solid-state laser device according to claim 5, wherein the support when the solid-state laser rod is arranged is supported by a reference surface of the solid-state laser rod.

Images