JPH0483388A - Laser oscillator - Google Patents

Abstract

PURPOSE:To control a beam intensity and a pulse width by simultaneously or individually operating first, second acoustooptical Q switch elements provided between a beam splitter and first, second output mirrors. CONSTITUTION:When a control power source 11 is turned ON and a first acoustooptical Q switch 20 is operated in a laser oscillating state, a pulse beam L1 is output from a first output mirror 16. When a second acoustooptical Q switch element 21 is operated, a pulse beam L2 is output from a second output mirror 18. In this operation, when the repetition numbers of the switches 20, 21 are set to 1/2 and they are operated simultaneously by deviating the timing at half, two pulse beams having equal peak intensities to that when they are individually operated, are output. Thus, input energies to the beams L1, L2 can be altered, and the peak intensities and the pulse widths of the beams can be controlled to certain degree.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a laser oscillation device, and particularly to a device for obtaining two laser beams from one oscillation device.

(Prior art) When obtaining two laser beams from one laser oscillation device, it is necessary to split them into two using a beam splitter, or for pulsed laser beams, use a rotating mirror that rotates at high speed in synchronization with the pulse repetition frequency. It was common practice to guide the flow in two directions. However, with a beam splitter, if the beam is divided into approximately equal parts, the intensity will be approximately 1/2.
Depending on the type of processing, laser processing may not be possible due to insufficient beam intensity. Furthermore, in the case of a rotating mirror, synchronization is difficult, resulting in poor stability in the beam exit direction, which poses a practical problem. In addition to the techniques described above, a technique disclosed in Japanese Patent Laid-Open No. 55-77187 is known.

As shown in FIG. 2, this technology includes a laser oscillator (1), and the output laser light is made to enter a Pockels cell (2). (3) is a timing circuit that generates a pulse voltage for operating the Q switch of the laser oscillator (1) shown in Fig. 3 (al) and a pulse voltage for controlling the Pockels cell (2) shown in Fig. 3 (b). (4) is a polarizer provided at a position where the laser beam transmitted through the Pockels cell (2) is incident, and has two output ends (5) and (6) that are orthogonal to each other.

With the above configuration, when the laser oscillator (1) is applied with a pulse voltage for Q-switch operation, it emits a giant pulse laser beam as shown in FIG. 3(e). On the other hand, the Pockels cell (2) changes the polarization direction of the input laser beam by 90 degrees when the control pulse voltage is applied. That is, if the polarization direction of the output laser beam from the laser oscillator (1) is the direction A in FIG. 2, the polarization direction of the laser beam emitted by the Pockels cell (2) upon application of the control pulse voltage is the direction B in the same figure. The direction is perpendicular to the paper as shown in . The polarizer (4) receives the laser light emitted from the Pockels cell (2), and when the laser light is in the above-mentioned direction A, it directly emits the laser light from the output end (5) as shown in Figure 3 (+I). However, in the case of the above B direction, from the output end (6) to Fig. 3 (e)
The laser beam shown in is emitted.

(Problem to be Solved by the Invention) In the case of Figure 2 above, a Pockels cell (2) is used to change the polarization for each pulse outside the laser oscillator (1), and a polarizer (4) is used to direct the beam in two directions. Since the laser beams are separated, it is difficult to control the laser intensity depending on the emission direction.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a laser oscillation device that can extract two laser beams whose beam intensity and pulse width can be controlled.

[Structure of the invention] (Means and effects for solving the problem) A laser excitation section, a high reflection mirror provided on one end side of the laser excitation section, and a high reflection mirror provided on the other end side of the laser excitation section. a first output mirror forming an optical resonator in pair with a reflecting mirror; a beam splitter provided between the output mirror and the laser excitation section; and an optical path of the laser beam split by the beam splitter. a second output mirror that is provided in and forms an optical resonator with the high reflection mirror;
First and second acousto-optic Qs provided between the beam splitter and the eleventh and second output mirrors, respectively.
By operating the first and second acousto-optic Q-switches simultaneously or individually, the two laser beams are output in various forms.

(Example) Hereinafter, the present invention will be explained based on drawings showing embodiments.

Figure 1 shows an embodiment of the present invention, in which (1G) is a control power supply (1G).
A laser head that receives a predetermined power supply from 1), which includes a solid laser medium (12) such as a YAG rod doped with neodymium, and an excitation means (13) such as a xenon lamp.
and a condensing reflector (14) with both of these installed at predetermined positions.
It is equipped with (15) is a high reflection mirror that is provided on one end surface of the laser head (10) with its reflective surface facing each other at a predetermined distance.

A first output mirror (16) is provided facing the other end surface of the laser head (15), and forms an optical resonator with the high reflection mirror (15) via the laser head (1H).

The other end surface of the laser head (10) and the first output mirror (1
A beam splitter (17) for splitting the beam almost equally into the optical path in 6) is provided with its partially reflecting surface inclined at 45 degrees to the other end surface. Beam splitter (
17), there is a second output mirror (
18) is provided, forming an optical resonator with the high reflection mirror (15). A first acousto-optic Q-switch element (20) is provided in the optical path between the first output mirror (16) and the beam splitter (17). Also,
A second acousto-optic Q-switch element (
21) is provided.

(22) are the first and second acousto-optic Q-switch elements (20
) (21) is a control unit that controls the timing of switching.

Next, the operation of the above configuration will be explained. Control power supply (11
) is turned ON, and in the state of laser oscillation, the first acousto-optic Q
When the switch (20) is operated, the first output mirror (
A pulsed beam (Ll) is output from the second output mirror (18) when the second acousto-optic Q switch element (21) is operated. In this operation, the number of repetitions of the first and second acousto-optic Q-switch elements (20) and (21) is set to 1.
/2 and operate simultaneously with half the timing difference, two pulse beams are output with the same peak intensity as when each is operated independently.

(Effect of the invention) First and second acousto-optic Q-switch elements (20), (2
]) By changing the operation timing shift, it is possible to change the input energy for each pulse beam (LIL (L2)), and the peak intensity and pulse width of these beams can also be controlled to a certain extent. In some cases, it is also possible to process different materials at the same time.Also, compared to a configuration in which the output laser beam is divided into two beams, the overall configuration of the device can be made smaller. .

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a block diagram showing a conventional example, and FIG. 3 is an operation waveform diagram of each part of FIG. 2. 011... Laser head 5... High reflection mirror 6... First output mirror 7)... Beam splitter 8... Second output mirror

Claims (1)

[Claims] A laser excitation section, a high reflection mirror provided at one end of the laser excitation section, and a first mirror provided at the other end of the laser excitation section and paired with the high reflection mirror to form an optical resonator. an output mirror, a beam splitter provided between the output mirror and the laser excitation section, and a second beam splitter provided in the optical path of the laser beam split by the beam splitter and forming an optical resonator with the high reflection mirror. output mirror and
first and second acousto-optic Qs provided between the beam splitter and the first and second output mirrors, respectively;
A laser oscillation device comprising a switch element.