JPH01201974A - Automatic alignment laser equipment - Google Patents

Abstract

PURPOSE:To simplify the arrangement of an automatic alignment laser equipment by having two sets or more of a pair of a heat detector disposed at opposite positions with an oscillating axis in-between at the rear face of a mirror of the total reflection side, performing a signal processing so as for the difference of the outputs of the detector disposed at opposite positions to become a predetermined size, and driving the mirror. CONSTITUTION:The equipment is formed of a set of an output mirror 2 and a total reflection mirror 1 disposed so as to sandwich an excitation medium 3. A heat detector 6 is disposed on the rear face of the total reflection mirror 1, and the temperature distribution on the surface of the mirror is measured. These heat detectors 6a and 6b, and 6c and 6d form respectively heat detector pairs disposed at symmetrical positions to the oscillating axis. A mirror adjusting screw 4 is moved by operating stepping motor 5a so as for the outputs of 6a and 6b to become equal, and the angle of the mirror in the upward and downward directions is adjusted. Further, a steeping motor 5b is operated so as for the outputs of 6c and 6d to become equal, causing a mirror adjusting screw 4b to move to adjust the angle of the mirror in the upward and downward directions. This makes it possible to obtain a highly reliable, simply- arranged, and inexpensive alignment system without degrading the quality of beams.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a laser device 1 that excites a laser medium and performs laser oscillation using a resonator, and particularly relates to an automatic alignment type laser device. Regarding.

(Prior Art) Conventionally, alignment of a laser resonator has generally been performed manually, except in research equipment. However, alignment of a racer requires considerable skill, and in the case of industrial lasers, it is common practice for an adjuster to go directly to the site and perform alignment. Therefore, there may be cases where the F-coracer cannot be used when necessary. Further, for the above-mentioned reasons, alignment cannot be carried out frequently, and the laser is often used in a poorly aligned state.

In order to improve these shortcomings, a laser device with an automatic alignment function is essential.

A conventional automatic alignment method is shown in FIGS. 3 and 4. The method will be explained below with reference to FIG. A part of the laser beam taken out from the output mirror 2 is bent by the partial reflection mirror 9, and a photodetector (or heat detector) t disposed opposite the optical axis t.
The light intensity at that location is converted into an electrical signal. and,
Alignment is performed by moving the mirror drive motor 5 using the differential amplifier 7 and the signal processing device 8 so that the outputs of the detectors placed opposite to the optical axis are equal. I am doing it.

However, this method has the disadvantage that the laser output is attenuated due to the insertion of a partially reflecting mirror in the beam optical path. A further disadvantage is that the quality of the laser beam deteriorates due to the thermal lens effect of the partially reflecting mirror. Furthermore, if the adjustment of the partial reflection mirror is incorrect, the beam position entering the detector will shift, making it impossible to achieve correct alignment. Therefore, it is necessary to accurately adjust the partial reflection mirror, and the alignment system is complicated. Become.

In addition, the method shown in Figure 4 uses a dielectric coated surface of a light-transmitting substrate as a total reflection mirror, and a portion of the emitted light is sent to a photodetector (or heat detector). ).

By employing this method, the above-mentioned disadvantages can be eliminated, but there is a disadvantage in that an inexpensive metal mirror with high light intensity cannot be used as the total reflection mirror. Furthermore, since a detector is installed behind the total reflection mirror, the configuration is complicated, although the method shown in FIG. 3 is not the same.

Furthermore, with the above two methods, it is almost impossible to align the folding mirror.

(Problems to be Solved by the Invention) As described above, in order to provide a stable and highly reliable laser device, a laser device having an automatic alignment device is essential. On the other hand, conventional alignment methods involve attenuation of laser output.

It had drawbacks such as reduced laser beam quality and complexity of the alignment system. The present invention aims to improve these drawbacks and provide a more excellent automatic alignment device.

[Structure of the invention]

(Means for Solving the Problems) The present invention has two or more pairs of heat detectors arranged opposite to each other with an oscillation axis sandwiched between them on the back surface of a mirror on the total reflection side, and Signal processing is performed so that the difference in output becomes a predetermined magnitude, and the mirror is driven, making the configuration extremely simple. At this time, the sensitivity of the detector can be further increased by making a hole in the back of the total reflection mirror and embedding a heat detector therein. Furthermore, by arranging a heat detector on the back surface of the folding mirror, it is also possible to align the resonator having the folding mirror.

(Function) The present invention has two or more pairs of heat detectors disposed on the back surface of the mirror on the total reflection side at positions f facing each other with the oscillation axis in between,
Signal processing is performed so that the difference between the outputs of the detectors at the opposite positions becomes a predetermined magnitude (-so that the boat fishing EC becomes equal), and the angle of the mirror is driven using a step motor, etc. It is something to do. As a result, the configuration of the device becomes very simple. Furthermore, the sensitivity of the detector can be further increased by making a hole in the back surface of the total reflection mirror and embedding a heat detector therein. The temperature distribution on the mirror surface is almost the same as the light intensity F in the resonator because the -rotate is absorbed on the mirror surface. Therefore, by comparing the outputs of the heat detectors placed on the back of the mirror and adjusting the mirror so that the light intensity within the resonator is axially symmetrical,
Alignment can be performed. In this way, in the present invention, since there is no need for light to leak to the back ff1 of the total reflection mirror, an inexpensive and highly durable metal mirror can be used for the total reflection mirror. Further, by using the present invention on the back surface of the folding mirror of the folding resonator, alignment of the folding resonator can be performed.

(Embodiment) FIG. 1 shows an embodiment of the present invention. A resonator is composed of a pair of mirrors placed to sandwich an excitation medium 3, and is composed of an output mirror 2 and a total reflection mirror 1.

A heat detector 6 is placed on the rear surface of the total reflection mirror to measure the temperature distribution on the mirror surface. It consists of a pair of thermal detectors, for example, two pairs arranged so that each pair is perpendicular to each other.In this case, the arrangement of the detector as seen from the direction of the laser oscillation axis and the rotation axis of the mirror The situation is shown in Fig. 5. 6a and 6b.

6d and 6d constitute a pair of heat detectors disposed at positions f symmetrical to the oscillation axis t, and the step motor 5a is operated so that the outputs of 6a and 6b are equal. Move the adjustment screw 4a to adjust the vertical mirror angle. Furthermore, by operating the step motor 5b so that the outputs of 6c and 6d are equal, the mirror adjustment screw 4b is moved to adjust the mirror angle in the left and right direction. By repeating the above two adjustments, mirror alignment is completed. The operation instructions for the step motors 5a and 5b are given by signal processing the detector output using a personal computer or the like. Of course, this may be done manually.

Further, any of the mirrors constituting the empathizer may be moved.

Further, for a folded resonator, alignment of the folded resonator can be performed by installing two or more pairs of heat detectors on the back surface of the total reflection mirror and the back surface of the folding mirror, respectively. An example of this case is shown in FIG.

In the present invention, the light intensity distribution inside the resonator is measured using two mirrors installed on the back surface of the total reflection mirror and on the back surface of the above-mentioned folding mirror.
This is done using more than one pair of heat detectors. This principle is based on the fact that the temperature rise on the mirror surface is approximately proportional to the light intensity distribution within the resonator due to slight light absorption on the mirror surface.

Therefore, by making a hole on the back side of the mirror and embedding the heat detector, the heat detector can be brought closer to the mirror surface1.
This improves measurement sensitivity.

As described above, by using the present invention, it is possible to provide an alignment system that is highly reliable, has a simple configuration, and is inexpensive, without impairing beam quality.

The present invention is of course applicable not only to stable resonators but also to unstable resonators, and it is only necessary to install a detector on the back surface of a concave mirror or a convex mirror. Furthermore, by installing these two mirrors at the same time on the back surface, alignment accuracy can be further improved.

As described above, the invention can be applied to various resonators and mirrors without departing from the effects of the invention.

〔Effect of the invention〕

By using the present invention, it is possible to provide an alignment system that is highly reliable, simple in construction, and inexpensive, without compromising beam quality.

Furthermore, it is possible to provide an alignment system that can relatively easily align folded resonators.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an automatic alignment device according to an embodiment of the present invention, FIG. 2 is a schematic diagram of an automatic alignment device for a folded resonator, also an embodiment of the present invention, and FIGS. The figure is a schematic diagram of a conventional automatic alignment device, and FIG. 5 is a schematic diagram showing the relationship between the detector position and the mirror rotation axis. 1. Total reflection mirror, 2. Output mirror, 3. Excitation medium, 4. Mirror adjustment screw, 5. Step motor, 6.
...detector, 7.. operational amplifier, 8. signal processing and motor drive device, 9.. beam splitter 110.. folding mirror, 1].. detector mounting mount, 12.. fulcrum, 13. mirror holder. .

Claims (3)

[Claims] (1) In a laser device that has a resonator consisting of a pair of mirrors optically arranged opposite to each other with an excitation region in between, a resonator is arranged opposite to each other across the oscillation axis on the back side of the mirror on the total reflection side. A signal processing device and a mirror driving device, each having two or more pairs of heat detectors arranged opposite to each other, and adjusting the angle of the mirror so that the difference in output between the opposingly arranged detectors becomes a predetermined magnitude. An automatic alignment type laser device comprising: (2) In a laser device in which a resonator consisting of a pair of optically opposed mirrors sandwiching an excitation region is folded back by one or more folding mirrors along the way, the folding mirror A pair of heat detectors are placed on the back side and on the back side of the mirror on the total reflection side, respectively, with the oscillation axis in between.
Automatic alignment comprising a signal processing device and a mirror driving device that adjust the angles of the mirrors so that the difference in output of the detectors arranged opposite to each other becomes a predetermined magnitude. type laser device. (3) The automatic alignment type laser device according to claim 1 and claim 2, wherein the heat detector is embedded in a hole formed in the back surface of the total reflection mirror and the back surface of the folding mirror.