| 摘要 |
A sensor having an interferometer, and a corresponding method, for use in the sensing of focal shifts in high energy laser beams are provided. The interferometer includes optical elements for generating a reference beam with a known wavefront phase curvature. In a preferred form of the invention, the reference beam is dithered and recombined with a sample beam, to produce a time-varying interference pattern indicative of the focal shift in the high energy laser beam. The interference pattern is focused by a lens onto a detector that produces electrical signals indicative of the detected interference pattern. The electrical signals are synchronously detected to remove the dither-frequency component, integrated, and amplified to generate a focal shift correction signal. The focal shift correction signal is then applied to an axially adjustable lens positioned to effect phase curvature changes in the reference beam wavefront to match those of the sample beam. The focal shift correction signals generated by the sensor are indicative of the high energy laser beam focal shift, and may be used for purposes of correcting these focal shifts.
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