We report a compact flat-top beam shaper fabricated by laser-assisted chemi
cal etching upon an ion-exchanged high-energy-beam-sensitive glass. The bea
m 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-le
vel patterns and one-step etching that are effective especially for such be
am shaper fabrication. The demonstrated beam shaper with good flatness and
edge features has an energy efficiency of 82%. (C) 1999 Society of Photo-Op
tical Instrumentation Engineers. [S0091-3286(99)02202-3].