Fabrication of large area diffractive optical elements by laser direct writing

We present a method to fabricate diffractive optical elements (DOEs) with four phase levels by the Laser Direct Writing technology. One computation method is provided to optimize the step depth, which could improve efficiency of DOEs. The step depth and imaging results demonstrate the fabricated DOEs devices with good optical properties. The effective areas of the DOEs pattern are as large as 49 cm
²
, which could be replicated easily for mass production applications.