Generation of flat-top focussed beams for percussion drilling of ceramic and metal

D. W. Coutts, M. J. Withford, J. A. Piper, G. Rutterford, A. I. Bell, M. R H Knowles

Research output: Chapter in Book/Report/Conference proceedingConference proceeding contribution

1 Citation (Scopus)

Abstract

In most laser micro-machining applications using copper vapour lasers, the system is configured for near-diffraction limited beam quality. This enables the beam to be tightly focussed to very small spot sizes and can be used for drilling very small holes or trepanning larger ones. The focused spot has a gaussian-like profile. In this paper a new laser system is presented that has a flat-top beam when focused. This has many advantages over gaussian beams when applied to percussion drilling and certain other applications. This system has demonstrated high speed percussion drilling of high quality 100 micron diameter holes in metals. We also report high speed (>200 holes/sec) percussion drilling in green sheet ceramic. The new laser system is a compact copper vapour laser (CVL) master-oscillator power-amplifier (MOPA) incorporating telescopic beam expansion in a high-gain double-pass amplifier. By configuring an oscillator for low coherence output and using a multimode optical fibre between the oscillator and a double-pass amplifier, high power (up to 34W) low divergence output beams having well defined flat-top far field beam profiles have been produced. This scheme generates a flat-top far-field beam profile by control of the spatial coherence of a flat-top near-field beam rather than the usual techniques of producing flattened gaussian beams from coherent gaussian beams. The output of such a MOPA has also demonstrated high power (34W average power, 80kW peak power) damage-free transmission through 100 micron core diameter optical fibres. This is of significant interest to system integrators and for certain applications.
Original languageEnglish
Title of host publicationProceedings of the Laser Institute of America
Subtitle of host publicationLaser Microfabrication Conference
EditorsEckhard Beyer, Rajesh Patel
Place of PublicationOrlando, USA
PublisherLaser Institute of America
Pages1-10
Number of pages10
ISBN (Print)0912035722, 9780912035727
Publication statusPublished - 2002
EventICALEO 2002 - 21st International Congress on Applications of Laser and Electro-Optics - Scottsdale, AZ, United States
Duration: 14 Oct 200217 Oct 2002

Other

OtherICALEO 2002 - 21st International Congress on Applications of Laser and Electro-Optics
CountryUnited States
CityScottsdale, AZ
Period14/10/0217/10/02

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  • Cite this

    Coutts, D. W., Withford, M. J., Piper, J. A., Rutterford, G., Bell, A. I., & Knowles, M. R. H. (2002). Generation of flat-top focussed beams for percussion drilling of ceramic and metal. In E. Beyer, & R. Patel (Eds.), Proceedings of the Laser Institute of America: Laser Microfabrication Conference (pp. 1-10). Orlando, USA: Laser Institute of America.