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
  • H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
  • H01S3/06—Construction or shape of active medium
  • H01S3/07—Construction or shape of active medium consisting of a plurality of parts, e.g. segments
• • 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
  • H01S3/06—Construction or shape of active medium
  • H01S3/0602—Crystal lasers or glass lasers
  • H01S3/0606—Crystal lasers or glass lasers with polygonal cross-section, e.g. slab, prism
• • 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
  • H01S3/09—Processes or apparatus for excitation, e.g. pumping
  • H01S3/091—Processes or apparatus for excitation, e.g. pumping using optical pumping
  • H01S3/0915—Processes or apparatus for excitation, e.g. pumping using optical pumping by incoherent light
  • H01S3/092—Processes or apparatus for excitation, e.g. pumping using optical pumping by incoherent light of flash lamp
  • H01S3/093—Processes or apparatus for excitation, e.g. pumping using optical pumping by incoherent light of flash lamp focusing or directing the excitation energy into the active medium
• • 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
  • H01S3/025—Constructional details of solid state lasers, e.g. housings or mountings
• • 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
  • H01S3/081—Construction or shape of optical resonators or components thereof comprising three or more reflectors
  • H01S3/0813—Configuration of resonator

Definitions

• This Invention relates to a compact, powerful, continuous wave multi-slab laser oscillator system, which, depending on the efficiency of its optical excitation sources produces single mode output beam powers in the range 1,000 watts to 25,000 watts continuously.
• the system has applications in defence, industrial workstations and in surgery.
• Prior art continuous wave laser oscillators emitting powers in excess of 1,000 watts have utilized carbon dioxide as the lasing medium emitting at a wavelength of 10.6 microns.
• Continuous wave solid state laser oscillators have been confined to arc lamp excited neodymium doped yttrium aluminium garnet rods although continuous wave ruby rods have been reported using exotic optical pumping configurations.
• these prior art continuous wave output rod laser oscillators have been limited to single mode beams of less than 400 watts due to thermally induced distortions resulting from the rod geometry where the outside surface of the rod is cooled more effectively than is their centre giving rise to the well known lensing effects which cause disasterous beam distortions.
• slab laser media In an effort to avoid the thermally induced distortions of rod laser media, slab laser media have been used with the beam amplification path zig zagging within the said slab via critical angle reflections off two optically polished faces through which the said slabs are excited.
• the problems with these prior art, internal cavity continuous wave slab laser oscillators is the fact that their output beam diameter is limited by the thickness of the said slabs, which in turn are limited by cooling problems, which lead to thermally induced distortions, and by the fa ct that self-oscillations of these prior art oscillators can take place from one end of the slab to the other without the need for beam zig-zag, a situation which leads to uncontrollable beam path emissions within the slab.
• Prior art continuous wave slab laser oscillators have also been limited by their excitation sources being unable to provide the pumping intensities required to exploit the full capabilities of the slab gain medium.
• My invention overcomes the defects of the prior art carbon dioxide laser oscillators which are excessively large due to the low density of laslng Ions in gases and demand complex and expensive gas recirculating systems.
• My invention overcomes the defects of prior art rod laser oscillators In that its geometry does not lend itself to thermally induced distortions.
• My invention overcomes the defects of prior art continuous wave, internal beam path slab laser oscillators but utilizing thin slab section where both the laser beam and the excitation light enter through the large optically polished faces of a series of slabs each one excited with a minimal amount of excitation light necessary to produce a given laser beam output power, with higher output powers being achieved by adding more optically excited slab sections rather than by increasing the optical excitation power into a single slab.
• my invention can utilize arrays of relatively low power semiconductor light sources for the optical excitation of the slabs as well as severely filtered outputs of arc lamps which result in only the absorbable excitation light entering the said slabs from said arc lamps.
• My invention also overcomes the self-oscillation problems of prior art slab oscillators in that there is only a single beam path defined for all slabs, said beam path fully utilizing the volume of each of the said slabs. In my invention, no two or more slabs are positioned so that spurious self-oscillations between said slabs can occur.
• the output beam diameter is not limited by the thickness of the slab.
• the present invention is not slab limited in its power output because continuous wave intensities of several kilowatts cm -2 are in order for slab and rod laser media and the area of the output beams can exceed 10 cm 2 implying power limitations In excess of 30 kilowatts.
• the present invention utilizes a larger number, up to 10, relatively expensive slabs of laser crystalline gain media to achieve its operating parameters so that the laser media Itself can cost in excess of $250,000, at least an order of magnitude greater than the laser media of prior art systems.
• the chances of damaging a given slab is much reduced because the optical excitation loadings per slab is much reduced.
• Another object of the invention is to provide a slab laser oscillator system whose output beam diameter is not limited by the thickness of the said slab. It is also another object of the invention to reduce the optical loadings an each slab by increasing the number of slabs so that low power optical excitation sources such as efficient semiconductor light sources can be used for excitation of the said invention.
• Another object of the invention is to arrange the series of slab laser media such that only the desired laser oscillator beam path is allowed, all spurious paths being suppressed.
• Yet another object of the invention is to reduce thermal loading on the slabs so that slab laser media of relatively poor thermal conductivity can be used for high power, high quality beam outputs.
• An object of the invention is to utilize laser beams of elliptical cross-section with elongated slab sections to achieve the higher output powers around 25,000 watts.
• Figure 1 shows the invention with ten slabs arranged in a series of five modules each slab being of the active mirror format and excited through both Its optically polished surfaces by well filtered optical outputs of arc lamps.
• the arrangement of the slabs and housings is such as to well define the laser oscillator cavity.
• Figure 2 shows the invention with a mixture of arc lamp and semiconductor light source optical excitation sources.
• FIG. 3 shows the invention with all of its excitation sources in the form of semiconductor light sources.
• numeral 1 is a 100% reflecting laser mirror whilst numeral 2 is a partially reflecting laser mirror, said mirrors defining the laser oscillator cavity containing the high quality laser beam of circular or elliptical cross-section indicated by numeral 3 which emits from the said laser oscillator cavity through 2 as the output beam indicated by numeral 4.
• Numeral 5 indicates the slab laser medium which is active mirrored of rectangular dimensions and of a size consistent with prevailing crystal growing techniques. Slab 5 is optically excited through both the rear mirrored surface and its front anti-reflection coated surface via the optical filter indicated by numeral 6 which, is water cooled.
• Numeral 7 indicates the aperture which defines both the path and cross-sectional area of the cavity beam 3.
• Numeral 8 indicates an optical window which allows the front of slabs 5 to be optically excited from the arc lamps indicated by numeral 9.
• Numeral 10 Indicates a reflector which directs a portion of the output of arc lamp 9 into slabs 5 via the water cooled optical filter 6.
• Numeral 11 indicates the flanges which allow the housings indicated by numeral 12 to be bolted together to form the layout of the Invention the water cooled housing 12 and its contents being indicated by number 13,
• numeral 14 indicates the water cooled semiconductor light sources which do not require filtering because its narrow band optical output can be tuned to match the absorption bands of laser slab media 5. Also the light source 14 does not require window 8.
• the invention has application as a compact, powerful laser oscillator head which can be attached onto the end of a robotic arm for applications in industrial workstations for welding, cutting and case hardening metallic objects and for cutting non-metallic objects.
• the invention can be installed in a hand held casing for surgical applications.
• the invention can be used as a laser beam transmitter for laser radar and target designators.

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• Physics & Mathematics (AREA)
• Electromagnetism (AREA)
• Engineering & Computer Science (AREA)
• Plasma & Fusion (AREA)
• Optics & Photonics (AREA)
• Chemical & Material Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Lasers (AREA)

Applications Claiming Priority (2)

Publications (1)

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ID=3771481

Family Applications (1)

Country Status (3)

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Family Cites Families (5)

• 1987
  • 1987-02-23 WO PCT/AU1987/000051 patent/WO1987005160A1/en unknown
  • 1987-02-23 AU AU70804/87A patent/AU598803B2/en not_active Ceased
  • 1987-02-23 EP EP19870901290 patent/EP0258321A1/de not_active Withdrawn

Non-Patent Citations (1)

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