WO2011132535A1

WO2011132535A1 - Optical glass rod, manufacturing method of optical glass rod, and laser generation device

Info

Publication number: WO2011132535A1
Application number: PCT/JP2011/058743
Authority: WO
Inventors: 康一梶山; 通伸水村
Original assignee: 株式会社ブイ・テクノロジー
Priority date: 2010-04-23
Filing date: 2011-04-06
Publication date: 2011-10-27
Also published as: TW201211577A; JP2011233591A

Abstract

The disclosed optical glass rod (6) provided with anti-reflection films (6a) on both end surfaces is positioned in the optical path of a laser resonator comprising a rear mirror and a front mirror in order to lengthen the optical light path. The optical glass rod (6) comprises a main body (6b) and a pair of end members (6c) which have a total length shorter than that of the main body (6b) and which have an anti-reflective film (6a) on one end surface. The other end surface of the end members (6c) is formed so as to be connected by optical contact to the end surfaces of the main body (6b). By this means, it is possible to form an optical glass rod (6) with an anti-reflective film (6a) on both sides even when the length of optical glass rod (6) required cannot normally be inserted into a vacuum evaporation device. Consequently, the disclosed optical glass rod with anti-reflective film can secure the necessary length without being limited to a rod length which can be accommodated in a vacuum evaporation device for forming the anti-reflective films.

Description

Optical glass rod, method of manufacturing optical glass rod, and laser generator

The present invention relates to an optical glass rod provided with antireflection films on both end faces, a method for manufacturing the optical glass rod, and a laser generator provided with the optical glass rod.

Conventionally, a laser device in which a high refractive index medium is arranged is known as means for controlling the optical path length in a laser resonator (see, for example, Patent Document 1).

JP 2008-060317 A

By the way, since the emission time (pulse width) of the laser beam becomes longer in proportion to the resonator length, geometrical resonance can be achieved by placing an optical glass rod (high refractive index medium) on the optical path in the resonator. Without changing the device length, the optical resonator length can be increased to increase the laser light emission time (pulse width). However, if the laser beam is reflected by the end face of the optical glass rod placed in the resonator, oscillation other than normal laser oscillation occurs, causing damage to optical components and lowering efficiency, so both end faces of the optical glass rod It is necessary to form an antireflection film on the surface.
However, in general, the antireflection film is formed by vacuum vapor deposition, but the length of the optical glass rod entering the vacuum vapor deposition machine is limited, so the length of the optical glass rod depends on the size of the vacuum vapor deposition machine. The limit is determined, and it is difficult to form an antireflection film on both ends of the required length of the optical glass rod, and the required laser light emission time (pulse width) may not be obtained.

Therefore, the present invention addresses such problems and is provided with an antireflection film that can secure the required length without being limited by the rod length that can be accommodated in a vacuum evaporation machine that forms the antireflection film. It is another object of the present invention to provide an optical glass rod and a method for producing the optical glass rod, and to provide a laser generator equipped with the optical glass rod.

In order to achieve the above object, an optical glass rod according to the present invention is an optical glass rod having antireflection films on both end faces, and has a main body member and an antireflection film having a shorter overall length than the main body member. It consists of a pair of end members provided on one end surface, and the other end surfaces of the end members are joined to both end surfaces of the main body member.
In such a configuration, an antireflection film is attached to both end faces by joining the other end face of the end member having the antireflection film on one end face (the face not having the antireflection film) to each of both end faces of the main body member. It is set as the optical glass rod provided with. Since the antireflection film is not formed on the main body member, it is not necessary to put in a vacuum vapor deposition machine in order to form the antireflection film, and the end member can be set to a length that cannot be accommodated in the vacuum vapor deposition machine. The antireflection film can be formed by setting the length so as to be accommodated in a vacuum vapor deposition machine.
Here, the other end surface of the end member can be joined to each end surface of the main body member by an optical contact.

On the other hand, the method for producing an optical glass rod according to the present invention is a method for producing an optical glass rod having antireflection films on both end faces, and the step of forming an antireflection film on one end face of each of the pair of end members. And joining the other end surface of the end member to each of both end surfaces of the main body member longer than the end member.
In such a configuration, after the antireflection film is formed on one end surface of the end member, the other end surface of the end member is joined to each of both end surfaces of the main body member, thereby providing the antireflection film on both end surfaces. An optical glass rod is manufactured.

Here, the bonding step includes polishing the both end surfaces of the main body member, polishing the other end surface of the end member, and the end member on each of the both end surfaces of the main body member. Joining the end faces with optical contacts.
In such a configuration, both end surfaces of the main body member, in other words, the joint surface with the end member are polished, and the other end surface (the surface on which the antireflection film is not provided) of the end member is polished. The other end surface of the end member is joined to each of both end surfaces by optical contact to form an optical glass rod having antireflection films on both end surfaces.

The laser generator according to the present invention includes a main body member and a pair of end members having an overall length shorter than that of the main body member and provided with an antireflection film on one end surface. The optical glass rod formed by joining the other end surfaces of the end members is disposed on the optical path in the resonator.
In such a configuration, the optical glass rod is composed of a main body member and an end member having an antireflection film, and the length of the main body member that does not form the antireflection film can be set to a required length. By arranging the optical glass rod on the optical path in the resonator, the optical optical path length of the resonator can be made sufficiently long, and the optical glass rod has antireflection films at both ends, so that it passes through the optical glass rod. It can suppress that a laser beam reflects on the both end surfaces of an optical glass rod.

Further, a Q switch, a laser rod provided with an excitation lamp, and the optical glass rod may be provided between a rear mirror and a front mirror constituting the resonator of the laser generator.
In such a configuration, the light energy of the excitation lamp is collected in the laser rod, so that light molecules are emitted from the laser rod, and reflection is repeated between the rear mirror and the front mirror, leading to laser light oscillation. Part of the oscillated laser beam is emitted from the front mirror to the outside. Here, since an optical glass rod having antireflection films at both ends is arranged on the optical path between the rear mirror and the front mirror, the optical optical path length between the rear mirror and the front mirror becomes long, and The laser light passing through the optical glass rod can be prevented from being reflected at both end faces of the optical glass rod. The Q switch blocks the laser beam once, stores the energy and then outputs it, so that the laser beam with high peak energy can be extracted.

According to the optical glass rod and the method for manufacturing the optical glass rod according to the present invention, the optical glass rod is constituted by joining the main body member and the end member having the antireflection film on one end surface. Is formed by vacuum deposition, it is not necessary to set the length of the main body member to enter the vacuum deposition machine, and the required length of the optical glass rod having antireflection films on both end faces can be easily secured. .

Further, according to the laser generator of the present invention, the length of the optical glass rod disposed on the optical path of the resonator can be easily set long, so that the optical path length of the resonator is suppressed while suppressing the geometric optical path length. The optical path length can be made sufficiently long to extend the laser light emission time (pulse width), and the anti-reflection film is provided on both end faces of the optical glass rod, so that the laser light is reflected at both end faces of the optical glass rod. Thus, it is possible to avoid the destruction of the optical component and the decrease in efficiency.

It is a figure which shows the laser generator (resonator) in embodiment of this invention. It is a figure which shows the optical glass rod in embodiment of this invention, (A) is an exploded view, (B) is a figure which shows a joining state. It is a figure which shows the manufacturing process of the optical glass rod in embodiment of this invention.

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
FIG. 1 shows a laser generator (resonator) provided with an optical glass rod according to the present invention.
A laser generator 1 shown in FIG. 1 includes a laser rod 2 serving as a laser oscillation source, an excitation lamp (flash lamp) 3 for exciting the laser rod, a rear mirror 4, a front mirror 5, an optical glass rod 6, and Q A switch 7 is provided.

As the laser rod 2, for example, a YAG rod can be used. Then, the excitation lamp 3 is arranged in parallel to the laser rod 2, and when the excitation lamp 3 is turned on, the energy of the lamp light is collected in the laser rod 2 and when the inside of the laser rod 2 is in a sufficient energy state, Laser molecules are emitted by emitting light molecules from the laser rod 2 and repeatedly reflecting between the two

mirrors

4 and 5.

The rear mirror 4 is a total reflection mirror, whereas the front mirror 5 (output mirror) transmits part of the laser light, and part of the oscillated laser light is emitted from the front mirror 5 to the outside.
The Q switch 7 first suppresses laser oscillation by lowering the Q value of the laser resonator, and when the number of particles in the excited state in the laser rod 2 becomes sufficiently large, the Q value of the resonator is rapidly increased. Raising the laser to generate laser light with high peak energy.

The optical glass rod 6 is a rod-shaped member made of optical glass, and by placing the optical glass rod 6 that is a high refractive index medium on the optical path of the laser light that repeatedly reflects between the two

mirrors

4 and 5, Without changing the distance (geometric optical path length) between the two

mirrors

4 and 5, the optical optical path length is increased, thereby extending the laser light emission time (pulse width).
That is, since the emission time (pulse width) of the laser light becomes longer in proportion to the resonator length L, the geometric resonator length L can be obtained by arranging the optical glass rod 6 on the optical path in the resonator. Without changing, the optical resonator length (optical optical path length) is lengthened, and the emission time (pulse width) of the laser light is extended.

Here, if the laser light is reflected at the end face of the optical glass rod 6, oscillation other than the normal laser oscillation occurs, causing damage to the optical components and lowering the efficiency. An antireflection film 6a is provided.
The antireflection film 6a is provided on the end face of the optical glass rod 6 as a layer having a different refractive index, and cancels the phase of the reflected light on the surface of the antireflection film 6a and the reflected light on the end face of the optical glass rod 6 by reversing the phases. For example, it is formed by vacuum deposition using an inorganic material such as SiO ₂ , TiO _2, or Ta ₂ O ₅ .

As shown in FIG. 2, the optical glass rod 6 includes a main body member 6b and a pair of end members 6c joined to both ends of the main body member 6b.
An antireflection film 6a is formed on one end surface of the end member 6c, and the other end surface of the end member 6c on the side where the antireflection film 6a is not provided and both end surfaces of the body member 6b are optically contacted. Be joined.
The length of the end member 6c is, for example, about 10 mm, whereas the length of the main body member 6b is, for example, more than 50 cm.

Here, the manufacturing method of the optical glass rod 6 will be schematically described with reference to FIG.
First, a main body member 6b and an end member 6c, which are optical glass rods each having a specified length, are prepared (step S11, step S21), and both end faces of the main body member 6b are precisely polished (step S12). .
On the other hand, for the end member 6c, one end surface provided with the antireflection film 6a is polished, and the other end surface (joint surface with the main body member 6b) not provided with the antireflection film 6a is precisely polished (step S22). After the polishing operation, an antireflection film 6a is formed on one end face of the end member 6c by vacuum deposition (step S23).
In the precision polishing of both end surfaces of the main body member 6b and the other end surface of the end member 6c, the surface accuracy that enables joining by optical contact, for example, surface accuracy = about λ / 10 is polished. The end member 6c may be formed with the antireflection film 6a after the polishing step.

When the polishing and the formation of the antireflection film 6a are finished, the other end surface of the end member 6c (the end surface on the side where the antireflection film 6a is not provided) is brought into close contact with both end surfaces of the main body member 6b, and bonded by optical contact. Then, the optical glass rod 6 provided with the antireflection film 6a on both end faces is formed (step S13).
As a method for joining the main body member 6b and the end member 6c, in addition to the optical contact, bonding with a UV adhesive (optical adhesive) that has high transparency and does not absorb the laser oscillation wavelength is also possible. However, in the laser generator 1 having a large peak power of the laser beam by providing the Q switch 7 as in the present embodiment, the adhesive on the joint surface is easily destroyed by the laser beam, so that the optical contact as described above. It is more preferable to join the main body member 6b and the end member 6c by (optical welding).

According to the optical glass rod 6, since the antireflection film 6a is not provided on the main body member 6b, it is not necessary to put the main body member 6b in the vacuum vapor deposition machine, and therefore the length of the main body member 6b enters the vacuum vapor deposition machine. The length is not limited, and any length required for extending the optical path length of the resonator can be set.
On the other hand, the end member 6c does not determine the length of the optical glass rod 6, but is bonded to both end faces of the main body member 6b in order to provide the antireflection film 6a at both ends. For example, a length (thickness) of about 10 mm is sufficient, and this is a length (size) that can be easily put into a general vacuum deposition machine.
Therefore, even when the length of the optical glass rod 6 is required to be difficult to put into a general vacuum vapor deposition machine, antireflection films 6a formed by the vacuum vapor deposition machine are provided at both ends. An optical glass rod 6 can be formed.

Further, if the main body member 6b and the end member 6c are joined by optical contact, the joining surface is not broken in the laser generator 1 that generates a high-power laser, and an adhesive is used. Therefore, there is no dissolution / elution from the bonding surface, and laser light can be generated stably.
Further, if the optical glass rod 6 is provided on the optical path in the resonator, the length of the optical glass rod 6 is set to a length necessary for extending the laser light emission time (pulse width) to the required level. It is possible to emit laser light having a required light emission time.
In addition, the antireflection films 6a provided on both end surfaces of the optical glass rod 6 suppress the reflection of the laser light on both end surfaces of the optical glass rod 6, so that it is possible to prevent oscillation other than normal laser oscillation. It is possible to avoid destruction of optical parts and decrease in efficiency.

In the above embodiment, the optical glass rod 6 formed by joining the main body member 6b and the end member 6c provided with the antireflection film 6a is disposed on the optical path in the resonator. The arrangement of is not limited to within the resonator.
For example, the laser light emitted from the laser generator 1 is separated into two light beams by a polarization beam splitter, etc., and the optical path length of one of the separated light beams is made longer than the other light beam, and the optical path length difference is given. By combining the two luminous fluxes, the optical glass rod 6 is arranged on the optical path of the luminous flux giving a long optical path length in the configuration for extending the emission time (pulse width) of the laser light, and the geometrical optical path length An optical path length difference longer than the difference can be given.
Further, when the optical glass rod 6 is disposed in the resonator, the laser generator may not be provided with a Q switch in the resonator, and an SHG crystal or a THG crystal is disposed on the optical path in the resonator. The laser generator may be used.

DESCRIPTION OF SYMBOLS 1 ... Laser generator 2 ... Laser rod 3 ... Excitation lamp 4 ... Rear mirror 5 ... Front mirror 6 ... Optical glass rod 6a ... Antireflection film 6b ... Body member 6c ... End member 7 ... Q switch

Claims

An optical glass rod having antireflection films on both end faces,
A main body member and a pair of end members having a shorter overall length than the main body member and provided with an antireflection film on one end surface. The other end surface of the end member is joined to each of both end surfaces of the main body member. An optical glass rod.
The optical glass rod according to claim 1, wherein the other end surface of the end member is joined to each of both end surfaces of the main body member by optical contact.
A method for producing an optical glass rod having antireflection films on both end faces,
Forming an antireflection film on one end face of each of the pair of end members;
Bonding the other end surface of the end member to each of both end surfaces of the main body member longer than the end member;
The manufacturing method of the optical glass rod containing this.
Performing the joining comprises:
Polishing both end faces of the body member;
Polishing the other end surface of the end member;
Bonding the other end surface of the end member to each of both end surfaces of the body member by optical contact;
The manufacturing method of the optical glass rod of Claim 3 containing this.
A main body member and a pair of end members each having a shorter overall length than the main body member and provided with an antireflection film on one end surface. The other end surface of the end member is joined to each of both end surfaces of the main body member. A laser generator in which an optical glass rod is arranged on an optical path in a resonator.
6. The laser generator according to claim 5, further comprising: a Q switch, a laser rod provided with an excitation lamp, and the optical glass rod between a rear mirror and a front mirror constituting a resonator of the laser generator. .