LASER DIRECT-WRITE GRAY-LEVEL MASK AND ONE-STEP ETCHING FOR DIFFRACTIVE MICROLENS FABRICATION

High-efficiency diffractive optical elements can be achieved by an inc rease in the number of phase levels. We present a technique for laser direct-write gray-level masks on high-energy-beam-sensitive glass and one-step etching on the gray-level mask plate for the production of hi gh-efficiency diffractive optical elements. Sixteen-phase-level diffra ctive microlenses and microlens arrays with a focusing efficiency of a pproximately 94% have been realized by use of the one-step nonphotolit hographic fabrication technique. (C) 1998 Optical Society of America.