JP2001094180A - Aperture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent heating of ambient members by reducing reflection and scattering of laser light. SOLUTION: An aperture 9 for reducing the diameter of a laser beam R, emitted from the end in the axial-direction of a laser rod through an opening 10. The aperture is made of a material through which the beam R can transmit, both surfaces of an edge 11 for reducing an excessive laser light Ra to reduce the diameter of the beam are provided as incident surfaces 12 perpendicular to the laser light R, and a notch having reflection surfaces 13 which totally reflects the laser light Ra entered from the planes 12 of incidence toward a prescribed interior.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aperture for stopping a laser beam.

[0002]

2. Description of the Related Art As shown in FIG. 5, in a general solid-state laser oscillator, a laser rod 2 (for example, a solid-state laser medium such as an Nd: YAG laser rod) and an excitation lamp 3 (krypton lamp) are provided in a housing called a cavity 1. , And a cavity 1 is positioned and installed on an optical surface plate, and a transmission mirror 4 (partially reflection mirror) and a reflection mirror 5 (total reflection) forming an optical resonator are provided before and after the cavity 1. A mirror), and the laser rod 2 is excited by turning on the excitation lamp 3 in the cavity 1 to emit light, and the light is reciprocated between the transmission mirror 4 and the reflection mirror 5 to reciprocate the laser rod 2. By repeating the input and output of the laser beam, optical resonance is caused to amplify the light energy, and the laser beam R can be oscillated through the transmission mirror 4.

In this type of laser oscillator, as shown in FIGS. 6 and 7, an opening 6 is provided between a cavity 1 and each of a transmission mirror 4 and a reflection mirror 5 located before and after the cavity 1. A thin metal plate-shaped aperture 7 is provided, and the edge 8 is passed through an opening 6 having a wedge-like shape in the thickness direction to limit an extra outer laser beam Ra having a required beam divergence angle. In this way, the beam diameter is reduced to maintain good beam quality with high directivity.

[0004]

However, the problem is that the excess laser light Ra limited by the metal aperture 7 is reflected and scattered and hits a member located around the aperture 7 to heat the surrounding member. was there.

The present invention has been made in view of the above circumstances, and has as its object to reduce the reflection and scattering of laser light and prevent heating of surrounding members.

[0006]

According to a first aspect of the present invention, there is provided an aperture for narrowing a beam diameter of a laser beam emitted from an axial end of a laser rod through an opening.
It is made of a material that transmits laser light, and both sides of the edge that restricts excess laser light and narrows the beam diameter are made incident surfaces perpendicular to the laser light, and the laser light incident from the incident surface is put into a predetermined inside. An aperture, characterized in that a notch having a reflecting surface for total reflection is formed at the tip of the incident surface,
It is related to.

According to a second aspect of the present invention, there is provided an aperture for narrowing a beam diameter of a laser beam emitted from an axial end of a laser rod through an opening, the aperture being made of a material that transmits the laser beam, and The side of the laser light emission side of the edge that restricts excess laser light and narrows the beam diameter is made an incident surface perpendicular to the laser light, and the laser light incident from the incident surface on the opposite side is inserted into the predetermined inside. A notch provided with a reflecting surface for total reflection toward the aperture.

According to a third aspect of the present invention, there is provided an aperture for narrowing a beam diameter of a laser beam emitted from an axial end of a laser rod through an opening, the aperture being made of a material that transmits the laser beam, and Both edges of the edge that restricts excess laser light and narrows the beam diameter form a wedge shape toward the opening, so that the laser light that has entered inside from one incident surface is reflected toward the predetermined inside by the opposite incident surface. The aperture is characterized by being formed.

In the first and second aspects of the present invention, preferably, a non-reflection coating which does not reflect laser light may be provided on the vertical incident surface.

In the first, second, third, and fourth aspects of the present invention, preferably, an absorber for absorbing the heat of the limited laser beam may be provided. A cooler for preventing heating may be provided.

According to the first and second aspects of the present invention, when the laser beam is passed through the aperture of the aperture to reduce the beam diameter, the excess laser beam to be limited is reduced from the vertical incidence surface at the edge. The light enters the inside of the aperture, is totally reflected by the notched reflecting surface, travels through a predetermined inside of the aperture, and is guided to the outside from a predetermined position of the aperture.

As described above, the laser beam limited by the edge of the aperture travels through a predetermined inside of the aperture instead of being reflected and scattered, and is guided to the outside from a predetermined position of the aperture. The member located around the aperture is not hit by the reflection and the scattering, so that the heating of the member around the aperture can be prevented.

According to the third aspect of the present invention, when the laser beam is passed through the aperture of the aperture to reduce the beam diameter, the excess laser beam to be restricted is incident on the inside of the aperture from one of the wedge-shaped entrance surfaces. At the same time, the light travels through a predetermined interior of a material that is reflected and transmitted by the opposite wedge-shaped incident surface, and is guided to the outside from a predetermined position of the aperture.

As described above, the laser beam limited by the edge portion travels through a predetermined inside of the aperture instead of being reflected and scattered, and is guided to the outside from a predetermined position of the aperture.
The limited laser light does not hit the members located around the aperture due to reflection and scattering, so that heating of the surrounding members can be prevented. Further, since the edge of the aperture is formed in a simple wedge-like shape, it can be easily molded, and the manufacturing cost can be reduced.

[0015] According to the fourth aspect of the present invention, the first aspect is provided.
If a non-reflection coating that does not reflect laser light is provided on the vertical incident surface in the invention according to claim 2, the laser light is reflected on the incident surface when extra laser light is incident on the edge of the aperture. Without reflection of laser light,
Scattering can be reliably prevented.

According to the fifth aspect of the present invention, when an absorbing material for absorbing heat of the limited laser light is provided, the laser light guided into the aperture is absorbed by the absorbing material. Can be prevented from being heated.

According to the sixth aspect of the present invention, if a cooler for preventing the heating of the absorbing material is provided, the heating of the absorbing material can be prevented, so that the heating of the edge and the absorbing material can be surely prevented.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

A first example of the aperture according to the embodiment of the present invention will be described with reference to FIGS. 1 and 2. An aperture 9 according to the first example is formed by forming an opening 10 in a thin plate at a central portion thereof. It is.

The aperture 9 is made of a transparent material such as optical glass, and is preferably made of sapphire,
Those having high light transmittance and high thermal conductivity such as YAG are desirable.

The edge 11 of the aperture 10 of the aperture 9 has an incident surface 12 perpendicular to the laser beam R on both sides in the thickness direction of the aperture 9 and has an anti-reflection coating. Has a reflecting surface 1 that totally reflects light.
3, a V-shaped notch 14 is formed.

On the other hand, the aperture 9 is provided with an absorbing material 15 such as a metal painted black so as to absorb heat, and the absorbing material 15 is provided with a cooler 16.

Hereinafter, the operation of the first embodiment of the present invention will be described.

When the laser beam R is passed through the aperture 10 of the aperture 9 to reduce the beam diameter, the limited surplus laser beam Ra enters the inside of the aperture 9 from the vertical incidence surface 12 of the edge 11. The light is totally reflected by the reflection surface 13 of the notch 14, travels through a predetermined portion of the aperture 9, and is guided from a predetermined position of the aperture 9 to an external absorber 15.

The laser beam Ra guided to the absorber 15 turns into heat and heats the absorber 15, but at the same time, the absorber 16 is cooled by the cooler 16, so that the temperature rise of the absorber 15 is prevented.

As described above, the laser beam Ra restricted by the edge 11 of the aperture 9 travels through a predetermined inside of the aperture 9 instead of being reflected and scattered, and is guided to the outside from a predetermined position of the aperture 9. The reflected laser light Ra does not hit a member located around the aperture 9 due to reflection and scattering, and can prevent heating of the surrounding members.

If a non-reflection coating that does not reflect the laser light Ra is provided on the vertical incident surface 12, the extra laser light R
a is incident on the edge 11 of the aperture 9,
2, the laser light Ra is not reflected, and the reflection and scattering of the laser light Ra can be reliably prevented.

Further, if the aperture 9 is provided with an absorbing material 15 for absorbing the heat of the limited laser light Ra, the laser light Ra guided into the aperture 9 is absorbed by the absorbing material 15, and 11 can be prevented from being heated.

Furthermore, if a cooler 16 for preventing the heating of the absorbing material 15 is provided, the heating of the absorbing material 15 can also be prevented, so that the heating of the edge portion 11 and the absorbing material 15 can be reliably prevented.

A second example of the aperture according to the embodiment of the present invention will be described with reference to FIG. 3. The aperture 17 of the second example is configured such that the edge 11 of the aperture 9 of the first example is shifted from the one incident surface 12. Intermediate position of notch 14, that is, reflecting surface 1
The shape is up to three.

More specifically, the edge 19 of the opening 18
Has a side surface on the emission side of the laser light R formed on an incident surface 20 perpendicular to the laser light R and provided with a non-reflection coating. A notch 22 on an inclined surface is formed so as to form a reflection surface 21 that totally reflects the light.

The aperture 17 is made of a transparent material such as optical glass, similarly to the aperture 9 of the first example, and preferably has high light transmittance and high thermal conductivity such as sapphire and YAG. It is desirable to have one.

On the other hand, the aperture 17 is provided with an absorbing material such as metal painted black so as to absorb heat.
The absorber has a cooler.

The operation of the second embodiment of the present invention will be described below.

After passing through a transmission line, an amplifier, etc., the laser light R
Is only from one direction, and when the laser beam R is passed through the opening 18 of the aperture 17 to reduce the beam diameter, the limited excess laser beam Ra is applied to the vertical incident surface 20 of the edge 19.
The light enters the predetermined inside of the more transparent material, is totally reflected by the reflection surface 21 of the notch 22 on the opposite side, travels through the predetermined inside of the aperture 17, and is guided from the predetermined position of the aperture 17 to the external absorbing material.

The laser beam Ra guided to the absorber becomes heat and heats the absorber, but at the same time, the absorber is cooled by the cooler, so that the temperature rise of the absorber is prevented.

As described above, the laser beam Ra restricted by the edge 19 of the aperture 17 travels through a predetermined inside of the aperture 17 instead of being reflected and scattered, and is guided to the outside from a predetermined position of the aperture 17. Functions substantially similar to those of the first example can be obtained.

A third example of the aperture according to the embodiment of the present invention will be described with reference to FIG. 4. The aperture 23 of the third example is obtained by modifying the shape of the edge 11 in the aperture 9 of the first example. .

The edge 25 of the opening 24 of the aperture 23
Both surfaces are formed in the shape of a wedge toward the opening, and the specific shape of the wedge is such that the laser light Ra is incident on the inside of the aperture 23 from one of the incident surfaces 26 while the other is the incident surface 26, and the other side is formed on the opposite side. It is formed at an angle at which the light is reflected toward a predetermined inside on the incident surface 26.

Here, the material of the aperture 23 is a material such as optical glass that transmits light similarly to the aperture 9 of the first example, and preferably a material having high light transmittance and high thermal conductivity such as sapphire or YAG. Is desirable.

The aperture 23 is provided with an absorbing material such as a metal painted black so as to absorb heat, similarly to the aperture 9 of the first example, and the absorbing material is provided with a cooler. .

Hereinafter, the operation of the third example of the embodiment of the present invention will be described.

When narrowing the beam diameter by passing the laser beam R through the opening 24 of the aperture 23, the limited excess laser beam Ra enters the inside of the aperture 23 from one of the wedge-shaped entrance surfaces 26, and becomes wedge-shaped. The light is reflected by the opposite incident surface 26 and travels through a predetermined portion of the aperture 23 to form the aperture 2.
3 is guided to the outside from a predetermined position.

Here, the aperture 23 of the third example reflects approximately 5% of the laser light R on the incident surface 26, but was able to sufficiently prevent the members located around the aperture 23 from being heated.

Next, the laser beam Ra guided to the absorbing material turns into heat to heat the heat absorbing material. At the same time, the heating material is cooled by the cooler, thereby preventing the temperature of the heating material from rising.

As described above, the laser beam Ra limited by the edge portion 25 of the aperture 23 travels inside a predetermined portion of the aperture 23 instead of being reflected and scattered, and is guided to the outside from a predetermined position of the aperture 23. The reflected laser light Ra does not hit a member located around the aperture 23 due to reflection and scattering, so that heating of the surrounding member can be prevented. Further, since the edge 25 of the aperture 23 has a simple wedge-like shape, it can be easily molded, and the manufacturing cost can be reduced.

Further, the operation of the third example of the embodiment of the present invention can obtain the same operation as that of the first example.

It should be noted that the aperture of the present invention is not limited to only the above-described embodiment, and it is needless to say that various changes can be made without departing from the gist of the present invention.

[0049]

According to the first and second aspects of the present invention, the laser light limited by the edge of the aperture is:
Instead of being reflected and scattered, the laser beam travels through a predetermined inside of the aperture and is guided to the outside from a predetermined position of the aperture.Therefore, the limited laser light does not hit members located around the aperture due to reflection and scattering. Heating of the member can be prevented.

According to the third aspect of the present invention, the laser beam limited by the edge portion travels through the predetermined inside of the aperture instead of being reflected and scattered, and is guided to the outside from the predetermined position of the aperture. The reflected laser light does not hit the members located around the aperture due to reflection and scattering, so that heating of the surrounding members can be prevented. In addition, the edge of the aperture has a simple wedge shape, so it can be easily molded,
Manufacturing costs can be reduced.

According to the fourth aspect of the present invention, the first aspect
If a non-reflection coating that does not reflect laser light is provided on the vertical incident surface in the invention according to claim 2, the laser light is reflected on the incident surface when extra laser light is incident on the edge of the aperture. Without reflection of laser light,
Scattering can be reliably prevented.

According to the fifth aspect of the present invention, when an absorbing material for absorbing heat of the limited laser light is provided, the laser light guided into the aperture is absorbed by the absorbing material. Can be prevented from being heated.

According to the sixth aspect of the present invention, if a cooler for preventing the heating of the absorbing material is provided, the heating of the absorbing material can be prevented, so that the heating of the edge portion and the absorbing material can be surely prevented.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a first example of an embodiment of an aperture according to the present invention.

FIG. 2 is a schematic diagram showing a state where an aperture and a cooler are provided in the aperture of the first example.

FIG. 3 is a longitudinal sectional view showing a second example of the embodiment of the aperture according to the present invention.

FIG. 4 is a longitudinal sectional view showing a third embodiment of the aperture according to the present invention.

FIG. 5 is a schematic plan view showing an example of a general solid-state laser oscillator.

FIG. 6 is a longitudinal sectional view showing an example of a conventional aperture.

FIG. 7 is a plan view showing an example of a conventional aperture.

DESCRIPTION OF SYMBOLS 2 Laser rod 9 Aperture 10 Opening 11 Edge 12 Entrance surface 13 Reflection surface 14 Notch 15 Absorber 16 Cooler 17 Aperture 18 Opening 19 Edge 20 Entrance surface 21 Reflection surface 22 Notch 23 Aperture 24 Opening 25 Edge 26 Incident surface R Laser light Ra Laser light

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Akihiro Nishimi 3-1-1-15 Toyosu, Koto-ku, Tokyo Ishikawajima Harima Heavy Industries, Ltd. Tokyo Engineering Center (72) Inventor Kenya Nakajima Toyosu 3-chome, Koto-ku, Tokyo 1-115 Ishikawajima-Harima Heavy Industries, Ltd., Tokyo Engineering Center (72) Inventor Yoshihisa Yamauchi 3-1-1, Toyosu, Koto-ku, Tokyo Ishikawajima-Harima Heavy Industries, Ltd. Tokyo Engineering Center F-term 5F072 AB02 AK01 KK01 KK09 KK26 MM08

Claims (6)

[Claims] 1. An aperture for narrowing a beam diameter of a laser beam emitted from an axial end of a laser rod through an opening, the aperture being made of a material that transmits the laser beam, and restricting an excessive laser beam. Both sides of the edge that narrows the beam diameter are made incident surfaces perpendicular to the laser light, and a notch with a reflecting surface that totally reflects the laser light incident from the incident surface toward a predetermined inside is provided at the tip of the incident surface. An aperture characterized by being formed. 2. An aperture for narrowing a beam diameter of a laser beam emitted from an axial end of a laser rod through an opening, the aperture being made of a material that transmits the laser beam, and restricting an excessive laser beam. The side face on the laser light emission side of the edge for narrowing the beam diameter is set as an incident surface perpendicular to the laser light, and a reflection surface for totally reflecting the laser light incident from the incident surface on the opposite side toward a predetermined inside is provided. An aperture, wherein a notch provided is formed. 3. An aperture for narrowing a beam diameter of a laser beam emitted from an axial end of a laser rod through an opening, the aperture being made of a material that transmits the laser beam, and restricting an excessive laser beam. Both sides of the edge for narrowing the beam diameter are formed in a wedge shape toward the opening, and the laser light incident inside from one incident surface is formed so as to be reflected toward a predetermined inside on the opposite incident surface. aperture. 4. The aperture according to claim 1, wherein a non-reflection coating that does not reflect laser light is provided on the vertical incidence surface. 5. The aperture according to claim 1, further comprising an absorber that absorbs heat of the limited laser light. 6. The aperture according to claim 5, further comprising a cooler for preventing heating of the absorbent.