Fabrication of diffractive phase elements by F2-laser ablation of fused silica

摘要: F 2 -laser ablation at 157 nm was used for generating sub-micron surface relief structures on fused silica to define binary diffractive phase elements (DPE). A pattern array of 128 x pixels excised using the F2 laser in combination with a high resolution processing system comprising CaF beam-homogenization optics and high-resolution Schwarzschild reflective objective. square projection mask provided precise excisions less than 10 μm spots, having sub-μm depths that were controlled by fluence number pulses provide required delay between ablated non-ablated pixels. Thus element (DPE) optimized first order UV spectral range made. four-level DPE design computed Iterative Fourier Transform Algorithm (IFTA) will be described an arbitrary irradiation without point symmetry two level design.