Novel laser beam propagation analyser
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The measurement of beam propagation parameters is essential for the wide ranging use of lasers in industry, medicine and academia. Commercially available devices to measure laser parameters such as M2 beam propagation ratio, divergence, Rayleigh distance and waist diameter are often slow, cumbersome and difficult to align.
The design concept was to remove the need for a movement stage, required to allow beam widths to be sampled as the stage moves through the laser caustic, and replace the fixed lens used in the standard configuration with one which can vary its optical power in response to a changing input voltage.
For this prototype a conventional convex lens was used to increase the optical power of the liquid lens. A low profile and high pixel-density CCD sensor was incorporated to allow the liquid lens to be placed close to the detection array. The distances between the lenses and camera were initially chosen to optimise the dynamic range of the device.