High-efficiency flat-top beam shaper fabricated by a nonlithographic technique

We report a compact flat-top beam shaper fabricated by laser-assisted chemical etching upon an ion-exchanged high-energy-beam-sensitive glass. The beam shaper combines a phase filter element and a focusing lens element into a single diffractive optical element with a quasi-continuous surface relief profile. The fabrication takes advantage of the laser generation of gray-level patterns and one-step etching that are effective especially for such beam shaper fabrication. The demonstrated beam shaper with good flatness and edge features has an energy efficiency of 82%.