Gas discharge lamp for active medium especially for lasers for laser amplifiers

Invention; refers to a gas discharge lamp for a. active environment, especially for lasers and laser amplifiers.

Known gas discharge lamps for active environments have smooth cylindrical and calibrated tubes of various materials. These gas discharge lamps are used in conjunction with resonators with a stable or even unstable configuration. When using an active environment with high amplification, different transverse electromagnetic modes propagate within the optical generator or amplifier due to the different velocities of the amplifier. Reflection reflexes occur on the smooth cylindrical wall of the tube. This makes the choice of modes considerably more difficult, since even higher modes are sufficient to vibrate the resonator due to reflexes on the smooth tube wall. This creates undesirable diffuse radiation. H. a small gas-discharge lamp, for example, a German DOS file no. 2,228,263 total expected total laser power.

When using such radiation, for example, the treatment of malathial, the energy density is considerably lower due to different radiation divergences. These disadvantages are smaller with the known thin tubes, since the ratio of mode-limited radiation to undesirable diffuse radiation is improved so that the enhanced radiation has a higher energy density. A disadvantage of the known designs is the relatively low power per meter of tube length and thus a considerable length of optical generators or amplifiers is necessary. However, there is a requirement that resonators be as cheap as possible, since lasers with a long construction length are very difficult

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229 752 achieves sufficient stability. In laser generators and amplifiers with a cylindrical crystal as the active medium, higher transverse electromagnetic modes can also be excited, but due to total reflection at the interface between the crystal and the environment. This phenomenon often occurs under high volumetric illumination of the active crystal. The radiation resulting therefrom has considerable disadvantages in further amplification and in focusing by optical elements.

The gas discharge lamp according to the invention for active environments, in particular for lasers and laser amplifiers, eliminates these disadvantages. SUMMARY OF THE INVENTION The gas discharge tube has an inner surface formed by wavy, ribbed, helical and / or other geometric shapes having a larger dimension in the radial, axial or circumferential direction of the tube than the wavelength of the amplified radiation. Suitably, the geometric shapes are arranged transverse to the longitudinal axis of the tube

Geometric shapes on the inner surface of the tube, which alternately increase and decrease the thickness of the tube and increase its surface, may be formed as point bulges, as repeating annular shapes of the same or unequal repetitive thickness and size or different thickness and size, e.g. .

The solution according to the invention allows a resonator 5 to be formed inside the laser resonator according to the selected configuration

229 752 tor field-limited radiation field without disturbances. When the lamp according to the invention is used as an amplifier, this construction acts as a faultless mode screen.

When using the gas discharge lamp according to the invention, by eliminating undesirable diffuse radiation, substantially improved radiation properties are obtained for machining the material. Due to the geometric shape of the gas discharge tube according to the invention, the power per meter of gas discharge is higher than that of the prior lamps, so that the length of the laser resonators can be reduced and the output power of the gas discharge laser resonator according to the invention can be increased.

The shape of the gas discharge tube can be adapted to the shape of rotationally symmetric crystals for solid phase lasers;

such a laser then generates mode-limited radiation. A further advantage of the invention is that due to the increased surface of the tube, the temperature of the plasma decreases here, thereby increasing the output power per meter of gas discharge.

The gas discharge lamp according to the invention is applicable to a stable laser configuration, since here also a clear mode limited field is created and thus an improved illumination of the active environment is achieved.

The invention is illustrated by way of example in the drawing. The gas discharge lamp 2, which is part of a laser (not shown), consists of a tube 13, the inner surface of which is corrugated

229 752 in sawtooth circumferential ribs. Other geometric shapes may be, for example, point protrusions, threaded grooves or annular grooves. Through the inlet 4 and the outlet 5 of the coolant, the tube 13 is cooled with a cooling 3. Inside the tube 13, a trouble-free, field-limited radiation field is created by the action of the totally reflective optical member 9 and the coupler member 8. In this case, the modes 10 with too much divergence and the resulting undesirable diffuse radiation are absorbed on the wall of the tube 13 and are thereby eliminated, so that the transmitted radiation 11 has slight bending losses and the divergence of the emitting radiation beam 12 is minimal. Through the electrode leads 7 s®.к the electrode feeds the required voltage to ignite the gas discharge.