Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
  • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
  • H01S3/14—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range characterised by the material used as the active medium
  • H01S3/22—Gases
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
  • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
  • H01S3/02—Constructional details
  • H01S3/03—Constructional details of gas laser discharge tubes
  • H01S3/0315—Waveguide lasers
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
  • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
  • H01S3/02—Constructional details
  • H01S3/03—Constructional details of gas laser discharge tubes
  • H01S3/038—Electrodes, e.g. special shape, configuration or composition
  • H01S3/0388—Compositions, materials or coatings
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
  • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
  • H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
  • H01S3/08—Construction or shape of optical resonators or components thereof
  • H01S3/08081—Unstable resonators
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
  • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
  • H01S3/14—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range characterised by the material used as the active medium
  • H01S3/22—Gases
  • H01S3/223—Gases the active gas being polyatomic, i.e. containing two or more atoms
  • H01S3/2232—Carbon dioxide (CO2) or monoxide [CO]

Definitions

• the invention relates to a stripline laser, as it is known for example from EP 0 305 893 A2 or US 4,719,639 A.
• Such a stripline or slab laser is a laser whose resonator is a combination of a waveguide resonator and an unstable resonator of the positive or negative branch.
• a gas mixture containing carbon dioxide CO 2 is located in a narrow discharge space formed between two flat plate-shaped electrodes. By applying a high-frequency electromagnetic field, the gas mixture located between the electrodes is excited. Opposite the end faces of the thus formed in this way narrow cuboid discharge space a Resonatorspie ⁇ gel is arranged.
• the resonator mirrors form an unstable confocal resonator with free beam propagation in a direction parallel to the narrow side of the discharge space.
• the propagation conditions of the resulting electromagnetic radiation within the discharge space are determined by the waveguide properties of the electrodes.
• the beam distribution in the direction of the unstable axis, ie, parallel to the electrodes and to the end face of the discharge space essentially by the Geometry of the resonator mirrors set.
• the surfaces of the electrodes In the direction perpendicular to instabi ⁇ len axis waveguide axis the surfaces of the electrodes have a limiting wall of the waveguide ent ⁇ decisive influence on the formation of the beam distribution in this direction.
• the properties of the surface, ie its roughness and the material of which they are made, as well as their mutual distance determine which resonator mode finds the most favorable propagation conditions.
• the electrodes are made of metal or a dielectric material.
• an electrically conductive metal for example aluminum, or a dielectric, for example aluminum oxide Al 2 O 3 , is mentioned as suitable material for the electrodes, wherein in the latter case an electrically conductive metal has to be arranged on the side facing away from the discharge space ,
• the influence of a dielectric coating of the surfaces of the electrodes facing the discharge space on the attenuation of the waveguide modes propagating in a cavity delimited by the electrodes is also known for conventional waveguide lasers, for example from US Pat. No. 4,875,218.
• the invention is therefore based on the object to provide a band ⁇ conductor laser with metallic electrodes, in which the above-mentioned problems are largely avoided.
• a gas mixture containing carbon dioxide CO 2 is sandwiched between two plate-shaped metallic electrodes lying opposite one another with their flat sides, which define a discharge space.
• a resonator is arranged in each case, which form an unstable resonator parallel to the flat sides.
• At least one of the mutually facing flat sides is either exclusively provided on at least one surface portion with a dielectric layer or on the entire flat side with a dielectric layer, in which case the thickness of the dielectric layer is greater on at least one partial area than in the rest ⁇ union region of the flat side.
• the invention is based on the finding that it is basically sufficient for suppressing unwanted modes to provide only a portion of at least one of the mutually facing flat sides, ie not the entire flat side of one of the electrodes with a thick dielectric layer, if the layer thickness is greater than that Thickness that would be required for a same damping effect causing dielectric layer applied over the entire flat side. Accordingly, it is sufficient to provide only a partial area with a dielectric layer due to the smaller surface area of this partial area can be applied to the electrode in a simpler and more accurately reproducible manner. This can be done either by providing only one partial area with a dielectric layer, ie that the remaining area of the flat side is not coated.
• partial surface for the present application is to be understood as meaning either a surface region in which the dielectric layer is thicker than in the remaining regions of the flat side or else a surface region which is the only region of the flat side which is a dielectric layer In practice it has proved to be a suitable layer thickness for these
• the dielectric layer is preferably aluminum ⁇ oxide Al 2 O 3 or silicon dioxide S1O 2 is provided.
• the at least one sub-area covers the focus, so that this is at least a partial area within the.
• Fig. 1 is a Bandleiter- or slab laser in a schematic plan view in which the dielectric layer provided with a partial area of one electrode is highlighted by Schraf ⁇ for at least
• a stripline or slab laser according to the invention comprises two plate-shaped metallic electrodes 6, 8 opposite each other with their flat sides 2, 4, which define a discharge space 10 extended in a longitudinal direction 9, in which a carbon dioxide CO 2 containing gas mixture is located as a laser-active medium.
• a resonator mirror 16, 18 is arranged in each case. The two resonator mirrors 16, 18 form an unstable resonator in a plane oriented parallel to the flat sides of the electrodes 6, 8.
• the illustrated example is a confocal unstable resonator of the positive branch, the focus of which is outside the resonator, that is outside of the fixed by the resonator mirrors 16, 18 space on the registered in the figure and parallel to the longitudinal direction resonator axis 19.
• the spreading between the Reso ⁇ natorapt 16, 18 laser beam LS is at the lateral edge of one of the end faces, in the example the end surface 14, coupled out.
• the electrodes 6, 8 are provided on their mutually facing flat sides 2, 4 with a dielectric layer 20 which is thicker on a in Fig. 1 highlighted by hatching part surface 21 than in the remaining region 22 and on the lateral Auskoppelrand 23, ie in the area the longitudinal side of the electric ⁇ 6, 8 is located, at which the laser beam LS parallel to the longitudinal direction 9 exiting the discharge space 10, and extending over the entire length between the opposite end faces 12 and 14 respectively.
• the partial surface 21 has a rectangular shape and its width b ent ⁇ speaks about the width of the coupled-out laser beam LS.
• both electrodes 6, 8 have a partial surface 21 in which the coating is thicker than in the remaining region 22.
• an embodiment is possible in which only the partial surface 21 of one or more surfaces of both electrodes are coated or at Both electrodes are provided with a dielectric layer 20 on their entire flat side, but only one of the electrodes has such a thicker coated partial surface 20.
• two concave resonator mirrors 16, 18 are provided, so that a confocal resonator of the negative branch is formed, whose common focus F lies within the resonator formed by the resonator mirrors 16, 18.
• this focus F is a line focus, which extends perpendicular to the Flachsei ⁇ th between the electrodes 6. 8
• the laser beam LS of a region G spreads mainly within half of that of the in the Fig. 3 are ⁇ recorded marginal rays 24, is limited 26th
• two partial surfaces 21 are provided with a thicker dielectric layer, which are opposite each other at the front edge of the
• Such an embodiment is also suitable for the positive-branch resonator shown in FIG.
• Electrodes 6, 8 be provided on the respective opposite end faces with such a thicker dielectric layer. Also in this embodiment, for stripline With a low output power, a coating can be provided exclusively in the partial areas 21 of at least one of the electrodes 6, 8. In the exemplary embodiment according to FIG. 4, in the case of a negative-branch resonator, the sub-area 21 is located exclusively in a zone surrounding the focus F, ie, at a distance from the lateral edge areas of the electrodes 6, 8.
• partial areas 21 are provided which cover the focus F and which are either in the transverse direction, ie in the transverse direction.
• H. Narrow band running parallel to the end faces extend as far as the longitudinal sides opposite one another (FIG. 5) or are arranged as a narrow band extending in the longitudinal direction between the opposite end faces (FIG. 6).
• the partial surface 21 is limited to the triangular areas within which the laser beam LS within the resonator mainly Ausbrei ⁇ tet.
• FIG 8 shows an embodiment with a positive-branch resonator, in which the partial surfaces 21 are located on the lateral edge of the electrodes 6, 8, on which the resonator axis 19 extends.
• FIGS. 1, 2, 3, 5 to 7, which extend in each case as far as the edges of the electrodes it is also possible in principle to provide partial surfaces which are at a distance from the latter Edges are.
• topological structures may be provided which deviate from the mainly illustrated rectangular or triangular shapes.
• the embodiments shown in FIGS. 1, 3 to 7 and in FIGS. 1, 3 and 8 can also be combined with each other.

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• Physics & Mathematics (AREA)
• Electromagnetism (AREA)
• Engineering & Computer Science (AREA)
• Plasma & Fusion (AREA)
• Optics & Photonics (AREA)
• Lasers (AREA)

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• 2011
  • 2011-01-26 DE DE102011003147A patent/DE102011003147B3/de active Active
  • 2011-11-29 EP EP11799257.8A patent/EP2668701A1/de not_active Withdrawn
  • 2011-11-29 WO PCT/EP2011/071281 patent/WO2012100866A1/de active Application Filing
  • 2011-11-29 JP JP2013550783A patent/JP5719038B2/ja active Active
• 2013
  • 2013-07-25 US US13/950,880 patent/US8913642B2/en active Active

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