Volume production of large gratings with excellent efficiency and wavefront performance is well established, making them a simple, low-cost alternative to large lenses, in addition to offering advantages only obtainable by freeform and diffractive optics.
The performance of many laser-based optical systems is improved by increasing beam size, often to enable higher intensity. Applications in materials processing range from cutting to annealing, while those in scientific research span laser fusion to particle acceleration. However, costs associated with large-format optical components such as lenses and mirrors as beam size increases can quickly become prohibitive due to fabrication challenges primarily in material production, polishing, and metrology. This paper considers an alternative approach to traditional optical components for large-format optical systems that has received relatively little attention to date: the use of diffraction gratings for basic beam management functions. As a simple example, by varying the period and orientation of grating fringes across its aperture, a grating can perform point-to-point imaging just like a lens (Fig. 1).
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