JPS61251089A - Discharge excitation type laser device - Google Patents

Abstract

PURPOSE:To enable the continuous variation of the output of the laser beam from zero by carrying out laser oscillation under the optimum conditions by providing a polarization control means and a polarization component selection means of the laser beam. CONSTITUTION:The laser beam 7 taken out from a laser oscillator A becomes a linear polarization. As a linear polarization element as a light detector 9 is arranged in the outside of the laser oscillator A, only the polarization component in a direction of the light detector 9 of the laser beam 7 is selected. Then, the pulse output of the laser beam 10 passed the light detector 9 changes continuously from zero by varying an angle theta made by the direction of the light detector 9 with the polarization direction of the laser beam 7. Accordingly, if the laser oscillation is carried out under the conditions for the most stable discharge and the light detector 9 is rotated mechanically, the pulse output of the laser beam 10 can be changed continuously from zero to the maximum value. It is also available to rotate the polarization direction of the laser beam due to Faraday effect by use of a Faraday element and a magnetic field generator before the laser beam reaches the light detector.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a discharge-excited laser device that can continuously change laser output.

[Conventional technology]

FIG. 4 is a block diagram of a conventional discharge-excited laser device described in, for example, page 137 of the proceedings of the 4th Japan Society of Applied Physics in 1984. In FIG. 0, (1) is the first main electrode;
(2) is a second main electrode placed opposite to the first main electrode (1).
(3) is a high voltage pulse circuit that applies a high voltage pulse between the main electrodes (1) and (2), and (4) is the laser medium provided between the main electrodes (1) and (2). It is.

(5) is a total reflection mirror, and (6) is a partial reflection mirror that forms an optical resonator together with the total reflection mirror (5), and these constitute a laser oscillator (A). (7) is this laser oscillator (A
) is a laser beam extracted from

Next, the operation will be explained. The first main electrode (1) and the second
Since the main electrodes (2) of the main electrodes (2) are arranged facing each other, when a high voltage pulse is applied between the main electrodes (1) and (2) by the high voltage pulse circuit (3), the laser medium (4) (main In the example, a glow discharge occurs in a high-pressure gas mixture of He, HCfi, and Xa), and the laser medium (4) becomes excited. The reflecting mirrors (5) and (6) constitute an optical resonator, from which a pulsed laser beam (7) is extracted.

In the conventional device, the output per pulse of the laser beam (7) was controlled by changing the voltage charged to the high voltage pulse circuit (3). However, when the charging voltage is changed, the electric field of the main electrodes (1) and (2) changes, the rise speed and duration of the glow discharge change, and the pulse waveform of the resulting laser beam (7) also changes. known to change.

FIG. 5 shows the pulse output of the laser when the charging voltage is changed, and the pulse output changes continuously between 23 and 30 kV. However, at 21%+, the discharge becomes uneven and the output decreases, and below that, glow discharge shifts to arc discharge and oscillation stops.

[Problem that the invention seeks to solve]

Since the conventional discharge-excited laser device is configured as described above, when the charging voltage is low, the rising speed of the discharge becomes slow and the glow discharge cannot be maintained, and the laser oscillation stops. Therefore, there is a problem in that it is difficult to continuously change the laser output from zero to the maximum output. There is also the problem that when the laser output is controlled by the charging voltage, the laser pulse waveform also changes.

The present invention was made to solve the above-mentioned problems, and an object of the present invention is to obtain a discharge-excited laser device that can continuously change the laser output per pulse.

[Means for solving problems]

A discharge-pumped laser device according to the present invention includes a laser oscillator, a polarization control means for a generated laser beam provided inside the laser oscillator, and a polarization component selection means outside the laser oscillator.

[For production]

In the discharge pumped laser device of the present invention, when a laser beam is generated by a laser oscillator, the generated laser beam is polarized by a polarization control means, and a specific polarization component is selected by a polarization component selection means provided outside the laser oscillator. . In this case, the charging voltage is set within a range that provides stable glow discharge, and the output per pulse is controlled by selecting a specific polarization component from the generated laser beam.

Therefore, the laser output can be changed smoothly from zero.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure is a block diagram of a discharge-excited laser device according to an embodiment of the present invention, and in the figure, (1) to (7) are the same as those in FIG. 4. (8) is a polarizer as a polarization direction control means provided between the reflecting mirrors (5) and (6) in the laser oscillator (A), and (9) is the laser beam (7) outside the laser oscillator (A). A laser beam (10) is a laser beam that has passed through the analyzer (9).

Next, the operation will be explained. The main electrodes placed opposite each other (
1), (2) When a high voltage pulse is applied between the pairs from the high voltage pulse circuit (3), a glow discharge is generated in the laser medium (4), and the laser medium (4) becomes excited. The reflecting mirrors (5) and (6) constitute an optical resonator, and if a polarizer (8) such as a linear polarizer, diffraction grating, prism, or bender mirror is placed inside the laser oscillator (A), The laser beam (7) extracted from the laser oscillator (A) becomes linearly polarized light. When a linearly polarizing element is placed as an analyzer (9) outside the laser oscillator (A), only the polarized component of the laser beam (7) in the direction of the analyzer (9) is selected. Therefore, if the angle between the direction of the analyzer (9) and the polarization direction of the laser beam (7) is θ, then by changing θ, the laser beam (10
) pulse output changes continuously from zero. The variation of the pulse output of the laser beam (10) with respect to θ is as shown in FIG. Therefore, if the laser oscillation is performed under conditions where the discharge is most stable and the analyzer (9) is mechanically rotated, the pulse output of the laser beam (10) can be changed continuously from zero to the maximum value. can.

In the above embodiment, the analyzer (9) was mechanically rotated as means for selecting the polarization of the laser beam, but the polarizer (8) placed in the laser oscillator (A) was controlled to change the polarization of the laser beam ( The polarization direction of 7) may be rotated, or the first polarization direction may be rotated.
In the embodiment shown in the figure, the analyzer (9) is mechanically rotated as a means for selecting the polarization of the laser beam, but as shown in Figure 3, before the laser beam (7) reaches the analyzer (9), Alternatively, the polarization direction of the laser beam (7) may be rotated by the Faraday effect using a Faraday element (11) and a magnetic field generator (12).The rotation angle due to the Faraday effect depends on the Welde constant and the strength of the magnetic field. Therefore, if water, benzene, or the like is used as the material for the Faraday element (11), the Weerde constant is large in the ultraviolet range, so it has a great effect on rotation of polarized light. Furthermore, in the embodiment shown in FIG. 3, even if the polarized light is changed to elliptically polarized light by using the electro-optic effect instead of using the Faraday effect, the same effect as in the previous embodiment can be obtained.

Further, in the above embodiment, the polarization direction control means uses linearly polarized light, but circularly or elliptically polarized light may also be used.

〔Effect of the invention〕

As described above, since the present invention provides the number f, the polarization control means for the laser beam, and the polarization component selection means, it is possible to perform laser oscillation under optimal conditions and to continuously change the pulse output of the laser beam from zero. is possible.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a discharge-excited laser device according to an embodiment of the present invention, FIG. 2 is a diagram showing changes in pulse output, and FIG. 3 is a block diagram showing another embodiment of the present invention. FIG. 4 is a block diagram of a conventional discharge-excited laser device, and FIG. 5 is a diagram showing changes in pulse output of the conventional device. (A) is a laser oscillator, (1) and (2) are main electrodes,
(5) and (6) are reflecting mirrors, (8) is a polarizer, and (9) is an analyzer. In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (4)

[Claims] (1) A discharge-pumped laser comprising a laser oscillator, a laser beam polarization control means provided within the laser oscillator, and a laser beam polarization component selection means provided outside the laser oscillator. Device. (2) A discharge-excited laser device according to claim 1, wherein the polarization component selection means rotates a linear polarization element. (3) A discharge-excited laser device according to claim 1, wherein the polarization component selection means comprises a Faraday element and a linear polarization element. (4) The discharge-excited laser device according to claim 1, wherein the polarization component selection means comprises an electro-optical element and a linear polarization element.