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Proceedings Paper

Continuous single pulse resolved measurement of beam diameters at 200 kHz using optical transmission filters
Author(s): Johannes Fruechtenicht; Andreas Letsch; Andreas Voss; Marwan Abdou Ahmed; Thomas Graf
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Paper Abstract

We present a novel laser beam measurement setup which allows the determination of the beam diameter for each single pulse of a pulsed laser beam at repetition rates of up to 200 kHz. This is useful for online process-parameter control e.g. in micromachining or for laser source characterization. Basically, the developed instrument combines spatial transmission filters specially designed for instantaneous optical determination of the second order moments of the lateral intensity distribution of the light beam and photodiodes coupled to customized electronics. The acquisition is computer-based, enabling real-time operation for online monitoring or control. It also allows data storage for a later analysis and visualization of the measurement results. The single-pulse resolved beam diameter can be measured and recorded without any interruption for an unlimited number of pulses. It is only limited by the capacity of the data storage means. In our setup a standard PC and hard-disk provided 2 hours uninterrupted operation and recording of varying beam diameters at 200 kHz. This is about three orders of magnitude faster than other systems. To calibrate our device we performed experiments in cw and pulsed regimes and the obtained results were compared to those obtained with a commercial camera based system. Only minor deviations of the beam diameter values between the two instruments were observed, proving the reliability of our approach.

Paper Details

Date Published: 6 February 2012
PDF: 10 pages
Proc. SPIE 8236, Laser Resonators, Microresonators, and Beam Control XIV, 82360F (6 February 2012); doi: 10.1117/12.906639
Show Author Affiliations
Johannes Fruechtenicht, Univ. Stuttgart (Germany)
Andreas Letsch, Univ. Stuttgart (Germany)
Andreas Voss, Univ. Stuttgart (Germany)
Marwan Abdou Ahmed, Univ. Stuttgart (Germany)
Thomas Graf, Univ. Stuttgart (Germany)

Published in SPIE Proceedings Vol. 8236:
Laser Resonators, Microresonators, and Beam Control XIV
Alexis V. Kudryashov; Alan H. Paxton; Vladimir S. Ilchenko, Editor(s)

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