Laser direct writing of diffractive structures on curved surfaces

Laser direct writing is a valuable tool for the fabrication of binary and grey scale diffractive structures. In the past genuinely hybrid elements, i.e. elements with surfaces that combine the refractive and diffractive approach, have proven to be very attractive for a wide range of applications. However, the production of such structures with high accuracy is a challenge. In this contribution we present a versatile laser direct writing system for the fabrication of such diffractive structures on curved substrates. Our system makes use of a non-perpendicular exposure technique. We will address the challenges implicated by that writing method e.g. tight focusing on the tilted surface.