JP2000180741A - Laser beam distributing apparatus and laser device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser beam distribution device of which the laser beam characteristics and the optical axis of the laser beam do not change, and is easy to handle, and is also capable of distributing the laser beam to many measurement instruments for simultaneously measuring the characteristics of the laser beam by them. SOLUTION: A plane mirror 2, arranged in a case 1 having an incident port, an exit port, and a distributing port, is controlled to turn based on the pulse timing detection signal of the laser beam. The plane mirror 2 has a reflecting surface area and a passing hole area and is arranged at a position intersecting the optical axis of the laser beam and is freely go in and out of the optical axis of the laser beam, and is arranged so that when the reflecting surface area is irradiated with the laser beam, the laser beam reaches a distribution port 15, and when the passing hole area is irradiated therewith, the laser beam travels straight and reaches an exit port 13, and the reflecting surface area is put in and out of the laser beam axis, according to the laser pulse timing signal and distributes the laser pulse to the exit port 13 and the distribution port 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser beam distribution device for transporting and distributing a laser beam to a place of use, and more particularly to a laser beam distribution device for distributing a laser beam formed by a pulse train. The present invention relates to a laser beam distribution device that can be used for a high-efficiency test device for distributing an output laser beam or simultaneously analyzing laser beams having the same characteristics obtained from one light source with another type of measurement device.

[0002]

2. Description of the Related Art Conventionally, as a method of distributing a conveyed laser beam to a use place, as shown in FIG. 9, one mirror is arranged on the laser beam optical axis and the laser beam is deflected from the optical axis. In some cases, as shown in FIG. 10, one beam splitter is arranged on the laser beam optical axis and the laser beam is divided into transmitted light and reflected light. In the method shown in FIG. 9, since the entire amount of the laser beam is supplied to any one location, the laser beam cannot be used at a plurality of locations at the same time.

Further, in the method shown in FIG. 10, the laser beam transmitted through the beam splitter is partially absorbed and the wavelength characteristic of the transmitted laser beam changes, so that accurate laser characteristic analysis cannot be performed. Further, since the beam splitter generates heat and is damaged by the absorption of the laser beam, high intensity light cannot be used. Furthermore, since the optical axis shifts in parallel during transmission through the beam splitter, there is a disadvantage that the optical axis needs to be readjusted at the place where the laser beam is used when the beam splitter is inserted and removed on the laser optical axis. there were. In addition, since the shift amount of the optical axis differs depending on the wavelength, when handling various laser beams, there is also an inconvenience that the optical axis needs to be readjusted every time the laser source is changed.

In the infrared region, zinc sulfide (ZnS) and zinc selenium (ZnS) are used as beam splitters.
e), KRS5 (IBrTa), sodium chloride (NaC
Although plates such as l) are used, these have the drawback of being toxic or deliquescent and difficult to handle.

[0005]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to make it possible to distribute a homogeneous laser beam to a large number of users, and to preserve characteristics in a large number of measuring devices arranged in parallel. An object of the present invention is to provide a laser beam distributing apparatus which does not change the laser beam characteristics, does not change the laser beam optical axis, and is easy to handle so that the laser beams can be simultaneously distributed. In particular, it is an object of the present invention to provide a laser beam distribution device capable of distributing a pulse discharge type laser beam to a required portion for each laser pulse.

[0006]

In order to solve the above-mentioned problems, a laser beam distribution device according to the present invention comprises a laser beam incident port, an output port through which the laser beam passes directly, and an output port through which the laser beam is deflected. A housing having a distribution port for distributing and emitting, a mirror provided in the housing,
The apparatus includes a mirror drive controller and a detector that detects a pulse timing of a laser beam and generates a signal.

The mirror has a reflective surface area and a through hole area,
The area is provided at a position intersecting with the optical axis of the laser beam, and the area is reciprocable with respect to the optical axis of the laser beam. When the light is irradiated, the light goes straight and reaches the emission port. The drive controller rotates the mirror based on the timing signal received from the laser pulse timing detector to position either the reflection surface area or the passage hole area on the laser beam axis, and emits the laser pulse. And distribution to the distribution ports.

According to the present invention, since the mirror only needs to have a structure in which a part has a total reflection area and a part has a hole through which a laser passes, it is difficult to use a material which is difficult to handle as in a conventional beam splitter. Instead, for example, a silicon or copper disk provided with an appropriate slit and plated with gold or the like to improve the reflectance of the reflection region can be used.

[0009] The laser beam passing through the mirror is emitted from the emission port without any change in the laser optical axis or the laser characteristics merely by passing through the space of the passage hole. Further, the laser beam deflected by the mirror and distributed to the distribution port is totally reflected by the reflection surface, so that the laser characteristics do not change similarly.

Further, since a required laser pulse group can be accurately distributed in synchronization with the pulse timing of the laser beam, energy intensity, micro pulse length,
Various measurements of laser pulses, such as polarization state and wavelength analysis, can be accurately performed. The timing of the laser pulse can be easily detected if the timing is based on, for example, a trigger signal from a laser oscillator.

The mirror can be rotated about an axis,
The drive controller may rotate the mirror axis to distribute the laser pulse to the emission port and the distribution port. With such a structure, the distribution control accurately synchronized with the laser pulse can be easily performed by using a simple rotary drive mechanism such as an electric motor.

The housing may be a vacuum container. When the laser beam has a wavelength in the infrared region, the characteristics may change or the container may generate heat by being absorbed by gas such as air or water vapor present inside the housing, and the transfer of the laser energy or the improvement of the laser characteristics may occur. Obstructs measurement. If the housing is a vacuum container, the inside of the housing can be evacuated to avoid such absorption and preserve the characteristics of the laser beam.
Note that by using the rotation introducing device, the mirror can be driven while maintaining the vacuum of the housing.

A position detection sensor is provided in the housing, and a detection signal for detecting the rotation position of the mirror is input to a drive controller, and the rotation and rotation of the mirror are controlled based on the position signal. can do. The detection signal of the position detection sensor becomes a feedback signal, and mirror rotation control can be performed more accurately. The rotation state of the mirror can be grasped, for example, by providing a notch or a protrusion on a predetermined portion of the mirror and detecting the contactlessly with an optical sensor or a magnetic sensor.

Further, a plurality of the above-mentioned laser beam distribution devices can be connected in series, and the laser beam supplied from the upstream can be arbitrarily distributed to the distribution ports of each stage.
When the entrance of the downstream laser beam distribution device is connected to the exit of the laser beam distribution device installed on the upstream side,
The laser beam supplied to the downstream laser beam distribution device is a laser beam that has just passed without undergoing any alteration except for the absence of the laser pulse group distributed to the distribution port by the upstream laser beam distribution device, Neither the laser characteristics nor the laser optical axis change. As described above, since the characteristics and optical axis of the laser beam propagating downstream of the laser beam distribution device do not change at all, the same applies even if any number of laser beam distribution devices are connected in series.

Therefore, even when the characteristics of the laser beam passing through the laser beam distribution device are measured, a correct measurement result can be obtained without being affected by the laser beam distribution device on the way. In addition, a large number of measuring instruments can be installed at the distribution port or the exit port of the laser beam distribution device at each stage to simultaneously measure various characteristics.
At this time, since there is no deviation of the optical axis, there is no need to perform optical adjustment even if the measurement conditions change, so that the measurement operation is easier and more accurate measurement results can be obtained than using a conventional laser beam distribution device. it can.

A laser device according to the present invention includes the above-described laser beam distribution device. The laser device has a great effect particularly when it generates an infrared laser or a free electron laser. This is because infrared rays are absorbed in a specific band by air or water vapor, and therefore it is preferable to avoid such selective absorption for use of a laser beam or characteristic measurement.

Further, the free electron laser is under research, and it is necessary to measure various characteristics of a laser pulse continuously sent from a laser generator. However, the free electron laser has large laser characteristics such as a wavelength, an intensity, and a laser pulse length. Because of the change in the range, the conventional apparatus cannot measure many measurement items at the same time, and it is necessary to reset the measuring instrument every time the measurement condition changes. By using the above laser beam distribution device, the laser characteristics are not affected by the distribution operation and the optical axis does not change depending on the measurement conditions, so the laser beam is distributed to many measurement devices. However, once the measuring device is correctly set, it is possible to simultaneously measure various characteristics of one laser beam.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a laser beam distribution device according to the present invention will be described in detail based on embodiments with reference to the drawings. FIGS. 1 to 6 are views for explaining a first embodiment of the present invention, and FIGS. 7 and 8 are drawings for explaining a second embodiment of the present invention.

[0019]

[Embodiment 1] FIG. 1 shows a laser beam distribution apparatus 1 according to the present invention.
It is a block diagram showing the laser device provided with the Example. The laser apparatus shown in FIG. 1 has an entrance 11 into which a laser beam enters, and an exit 1 through which a laser beam directly passes and exits.
3 and a distribution port from which a laser beam is deflected and emitted and 1
And a plane mirror 2 provided in the housing
A mirror drive controller 3, a position detector 4 for detecting the position of the plane mirror 2, and a laser generator 5 having a built-in detector for detecting a pulse timing of a laser beam and generating a signal. A synchronization control circuit 6 with a changeover switch 61 is provided.

The laser beam 51 emitted from the laser light source device 5 is introduced into the housing 1 through the entrance 11. An emission port 13 is provided on the optical axis extension of the laser beam 51, and is emitted from the emission port 13 when the laser beam 51 simply passes through the inside of the housing. The plane mirror 2 is installed at an appropriate position on the optical axis of the incident laser beam 51 so that the mirror surface has an appropriate angle with respect to the optical axis. The mounting angle of the mirror surface may be appropriately determined depending on the position and orientation of the distribution port 15, but if the angle is set to 45 degrees with respect to the optical axis, the structure of the laser beam distribution device is simplified.

FIG. 2 is a plan view showing an example of the mirror surface shape of the flat mirror 2. The mirror surface 21 is formed in a disk shape centered on the rotation shaft 23, has a reflection surface 25 having a surface perpendicular to the axis at a part, and has a notch 27 at a part. , Can rotate around the axis of rotation. Reflective surface 25
Is a polished surface of copper, which totally reflects infrared rays. Further, gold plating may be applied. In addition, the reflection surface 25 is provided on the outer periphery.
And projection 2 for position detection corresponding to the position of notch 27
9 are provided. Further, silicon also has a high reflectivity over a wide range of wavelengths, so that it can be used as a mirror material. FIG. 3 is a plan view showing another embodiment of the mirror surface 22 of the flat mirror.
6, the mirror surface 22 can be swung to move the reflection surface 26 into and out of the irradiation position of the laser beam 51.

The housing 1 is a vacuum container and includes a flat mirror 2
Is driven by a motor by a mirror drive controller 3 via a rotation introducing machine. As described above, the plane mirror 2 allows the reflection surfaces 25 and 26 to move in and out of the laser beam axis. When the laser beam 51 irradiates the reflection surface, the laser beam is reflected and emitted from the distribution port 15, and the reflection surface 25 and 26 are reflected. When the beam 26 is retracted from the laser beam optical axis, the laser beam goes straight and is emitted from the emission port 13. The housing 1 is
The laser beam 51 is mounted on an adjustment table 7 having a mechanism for adjusting the height and a mechanism for adjusting the front, rear, left and right positions, and can accurately adjust the position at which the laser beam 51 hits the plane mirror 2.

The laser beam 51 emitted from the laser generator 5 is composed of, for example, a laser pulse train of several tens of pps. The generation timing of the laser pulse can be known from the trigger signal of the laser generator, and is transmitted from the detector built in the laser generator 5 to the synchronization control circuit 6. The synchronization control circuit 6 controls the mirror drive controller 3 based on the timing of the laser pulse to control the positions of the reflection surfaces 25 and 26 of the plane mirror 2. In the case where the rotary flat mirror 2 as shown in FIG. 2 is used, the reflection surface 25 is positioned on the optical axis at the timing of the laser pulse to be branched to the distribution port 15 by the laser beam distribution device, and the other laser pulse The rotation speed is adjusted so that the notch 27 is located at the timing when comes.

FIG. 4 is a timing chart for explaining the distribution of laser pulses. FIG. 4A shows a laser beam 51 incident on the laser beam distribution device.
FIG. 4B shows the distribution laser beam 55 deflected by the reflection surface 25 and emitted from the distribution port 15, and FIG.
Represents a passing laser beam 53 emitted from the exit 13 through the laser beam. In the figure, the laser beam distribution device sends out one macro pulse for every four macro pulses to the distribution port 15, and at the timing of another macro pulse, the reflection surface 25 retreats from the laser optical axis position and passes through the exit port 13 as a passing laser beam 53. Has been released from.

As shown in FIG. 2, when the reflecting surface 25 and the notch 27 are distributed at a ratio of 1: 3 in the plane mirror 2, the plane mirror 2 is synchronized with the macro pulse timing. By rotating at a high speed, the distribution of the laser beam as shown in FIG. 4 is realized. In this case, the rotation speed of the plane mirror 2 is about 10 Hz. In order to rotate the mirror more accurately, the protrusion 29 on the periphery of the mirror surface 21 is required.
May be detected by the position detector 4 and fed back to the synchronization control circuit 6. The position detector 4 uses an optical sensor or a magnetic sensor to detect the passage of the protrusion 29 and generate a signal. A method of counting and estimating a method of distinguishing between the reflection surface 25 and the notch 27, a method of giving a difference in the projection shape, and the like can be used.

Even when the arrangement of the reflecting surface 25 on the plane mirror 2 is different from the interval between laser pulses to be distributed, the macropulse duration is short, so the macropulse time interval and the time when the reflecting surface 25 crosses the optical axis are determined. By determining the rotation speed of the plane mirror 2 in consideration of the interval, the distribution can be performed correctly. In addition, instead of rotating the plane mirror 2 at a constant speed, the reflection surface 25 using a pulse motor or the like is used.
By controlling the rotational position of the laser beam, the laser beam can be crossed at the correct timing. Also,
In the case of using an oscillating reflection mirror as shown in FIG. 3, the reflection surface 26 is inserted into the optical axis at the timing when the pulse to be distributed comes, and the control is made to retreat from the optical axis at other times. I just need.

The mode in which laser pulses are sampled and distributed at appropriate intervals in this manner is the first sampling mode, the mode in which all laser pulses are distributed to the distribution port 15 is the second sampling mode, and all laser pulses are emitted. The mode allocated to the mouth 13 is referred to as a third sampling mode.

FIG. 5 is a timing chart for explaining the distribution of laser pulses in the second sampling mode. In the second sampling mode, the reflection surfaces 25, 2
6 is always on the optical axis of the laser beam at the timing of the arrival of the laser pulse, and all the incident laser beams 51 shown in FIG. 5A are reflected on the reflection surfaces 25 and 2 as shown in FIG.
There is no laser beam deflected at 6 and emitted from the distribution port 15 and emitted from the emission port 13 as shown in FIG. The second sampling mode can be realized by controlling the rotation of the plane mirror 2, but can be easily realized by stopping the plane mirror 2 when the reflection surface 25 comes on the optical axis. All incident laser pulses are distributed to port 15
The second sampling mode is selected when it is desired to propagate the signal to the use place connected to.

FIG. 6 is a timing chart for explaining the distribution of laser pulses in the third sampling mode. In the third sampling mode, the reflection surface 2
6A are always out of the optical axis of the laser beam, and all the laser pulses of the incident laser beam 51 shown in FIG. 6A pass through as it is as shown in FIG. Then, as shown in FIG.
There is no laser pulse emitted from. The third sampling mode can be easily realized by stopping the plane mirror 2 when the notch 27 comes on the optical axis, and is selected when the incident laser pulse is directly propagated downstream. The selection of the sampling mode can be performed by giving an instruction to the synchronization control circuit 6 via the mode switch 61.

[0030]

Embodiment 2 This embodiment is a laser beam distribution device constructed by connecting the laser beam distribution devices of the first embodiment in series, and is used for distributing a laser beam to a plurality of locations. . FIG. 7 is a block diagram for explaining this embodiment, and FIG. 8 is a pulse timing chart showing an example of laser pulse distribution in this embodiment. The laser beam distribution device in the figure is a device in which three single laser beam distribution devices are connected in series, and the exit 83 of the most upstream laser beam distribution device 8 and the second stage laser beam distribution device 9
Are connected, and the output port 93 of the second-stage laser beam distribution device 9 and the entrance port 101 of the last-stage laser beam distribution device 10 are connected.

The laser beam a1 propagating from the laser generator (not shown) and entering the entrance 81 of the laser beam distributor 8 at the most upstream position is constant as shown in the uppermost graph (a1) in FIG. It is a laser beam having laser pulses at intervals. The incident laser beam a1 is transmitted to the plane mirror 8
FIG. 8 (b1) is deflected every predetermined pulse by 2
The laser beam is extracted as a distribution beam b1 having laser pulses at regular intervals as shown in FIG. The remaining laser pulse group is shown in FIG.
The light passes through the exit 83 and enters the entrance 91 of the laser beam distribution device 9 at the next stage as the passing beam a2 shown in 2).

A passing beam a2 shown in FIG. 8A and a distribution beam b2 shown in FIG.
And the distribution beam b2 is supplied from the distribution port 95 to the second laser use location. The distribution beam b2 is also a laser beam having equally spaced laser pulses. The passing beam a2 in the second-stage laser beam distribution device 9 is incident from the entrance 101 of the last-stage laser beam distribution device 10 and is transmitted by the plane mirror 102 to the passing beam c shown in FIG. ) Are distributed to the distribution beam b3. The distribution beam b3 is supplied from the distribution port 105 to the third laser use location, and the passing beam c is supplied from the emission port 103 to the fourth laser use location. The passing beam c and the distribution beam b3 in the last stage laser beam distribution device 10
Are also laser beams having laser pulses at equal intervals.

All of these distributed laser pulses are obtained by extracting one laser beam emitted from a laser generator for each laser pulse, and there is no laser beam in the propagation path that alters the laser characteristics. It has characteristics. Therefore, if a laser characteristic measuring device is installed at each place of use and simultaneously measured, various characteristics of the laser beam emitted from the laser generating device can be analyzed at once. Further, since the laser optical axis does not change depending on the laser wavelength once it is set, it is not necessary to adjust the position of the measuring device again even if the laser to be measured is changed. The laser beam distribution device at each stage can switch to the second sampling mode or the third sampling mode as needed to change the distribution destination. Also at this time, since the laser optical axis incident on the set measuring device does not change, there is no need to adjust the adjustment.

In the description of this embodiment, a case has been described in which three laser beam distribution devices are connected in series and the laser pulse group is equally distributed to four use locations. It is needless to say that there is no limitation and the distribution ratio and interval can be arbitrarily selected. When measuring the characteristics of the infrared laser, it is necessary to prevent the characteristics from changing due to the absorption band of air or water vapor, but the laser beam distribution device of the present invention distributes the laser beam in a vacuum vessel. Therefore, a change in characteristics can be avoided. In the case of measuring the characteristics of a free electron laser, the wavelength changes over a wide range. However, the laser beam distribution device of the present invention easily obtains accurate measurement results because the optical axis position has no wavelength dependency. be able to.

[0035]

As described above, the laser beam distribution device of the present invention makes it possible to distribute a uniform laser beam whose laser characteristics do not change to many users without changing the optical axis position. A homogeneous laser beam can be distributed simultaneously to a large number of measuring devices arranged in parallel.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a laser device having one embodiment of a laser beam distribution device according to the present invention.

FIG. 2 is a plan view showing an example of a mirror surface shape of a flat mirror used in the embodiment.

FIG. 3 is a plan view showing another example of the flat mirror used in the present embodiment.

FIG. 4 is a timing chart illustrating a distribution state of laser pulses in the present embodiment.

FIG. 5 is a timing chart illustrating a distribution state of laser pulses in a second sampling mode of the present embodiment.

FIG. 6 is a timing chart illustrating a distribution state of laser pulses in a third sampling mode of the present embodiment.

FIG. 7 is a block diagram showing a second embodiment of the laser beam distribution device of the present invention.

FIG. 8 is a pulse timing chart showing an example of laser pulse distribution in the present embodiment.

FIG. 9 is a conceptual diagram illustrating a conventional laser beam distribution method.

FIG. 10 is a conceptual diagram illustrating another example of a conventional laser beam distribution method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Housing 11 Inlet 13 Outlet 15 Distributor 2 Planar mirror 3 Mirror drive controller 4 Position detector 5 Laser generator 51 Laser beam 6 Synchronous control circuit 61 Mode switch 21, 22 Mirror surface 23, 24 Rotation axis 25, 26 Reflecting surface 27 Notch 29 Position detecting projection 7 Adjustment table 55 Distributed laser beam 53 Passing laser beam 51 Incident laser beam 8, 9, 10 Laser beam distribution device 83, 93, 103 Outgoing ports 81, 91, 101 Incident ports 85, 95, 105 Distributing ports 82, 92, 102 Flat mirror

Continued on the front page (72) Inventor Minoru Yokoyama 118 Futatsuka Noda City, Chiba Prefecture Kawasaki Heavy Industries Noda Factory F-term (reference) 2H041 AA14 AB13 AZ03 AZ06

Claims (8)

[Claims] 1. A housing having an entrance through which a laser beam enters, an exit through which the laser beam passes and exits, and a distribution opening through which the laser beam is distributed and exits, and is provided in the casing. A laser beam distribution apparatus comprising: a rotatable mirror having a reflection surface area and a through-hole area; a drive controller for the mirror; and a detector that detects a pulse timing of the laser beam and generates a signal. When the mirror irradiates the reflection surface area with the laser beam in the housing, the laser beam reaches the distribution port, and when the laser beam irradiates the passage hole area, the laser beam reaches the emission port. The drive controller rotates the mirror based on a signal from the detector to select the reflection surface area and the passage hole area to be positioned on the axis of the laser beam. A laser beam is distributed to the emission port and the distribution port. 2. The laser beam distribution device according to claim 1, wherein said mirror is rotatable, and is rotated by said drive controller to distribute said laser pulse to said emission port and said distribution port. . 3. The laser beam distribution device according to claim 1, wherein the housing is a vacuum vessel, and the drive controller drives the mirror by a rotation introducing device. 4. A position detection sensor for detecting a rotation position of the mirror is provided in the housing, and the drive controller controls rotation or rotation of the mirror based on a detection signal of the position detection sensor. 2. The method according to claim 1, wherein
4. The laser beam distribution device according to any one of claims 1 to 3. 5. A laser beam distribution device according to claim 1, wherein a plurality of laser beam distribution devices are connected in series, and a laser beam supplied from upstream is arbitrarily distributed to a distribution port of each stage. Laser beam distribution device. 6. A laser device comprising the laser beam distribution device according to claim 1. 7. An infrared laser device comprising the laser beam distribution device according to claim 1. 8. A free electron laser device comprising the laser beam distribution device according to claim 1.