title: Efficient optical elements to generate intensity weighted spot arrays: design and fabrication.
abstract: We report on the design and fabrication of fully 2-D surface relief diffraction elements that can split a single collimated beam into many beams in an arbitrary intensity distribution. These splitters were designed by computer using simulated annealing, and made into phase gratings by electron-beam lithography followed by plasma etching into quartz glass. Both two and four phase level gratings have been fabricated, allowing a wide range of uniform and weighted spot patterns to be generated. These grating elements have a measured diffraction efficiency of over 74%, with the beam intensity ratios accurate to within 1% of their target values.
authors.forename: M P
authors.initials: MP
authors.lastname: Dames
authors.forename: R J
authors.initials: RJ
authors.lastname: Dowling
authors.forename: P
authors.initials: P
authors.lastname: McKee
authors.forename: D
authors.initials: D
authors.lastname: Wood