Passive Optical Array Generators

Recent progress in designing and manufacturing space-invariant optical array generators is described. We begin by demonstrating Dammann gratings [1] that generate even-numbered arrays as large as 128x128, and odd-numbered arrays of up to 201x201 spots. The concept of a hybrid hologram [2] is applied to the fabrication of array generators, and extremely high-efficiency (close to 90%) components are obtained. Several novel types of array generators with multiple phase levels are introduced. These can e.g. reconstruct arrays with different fan-out at different angles of incidence. The application of rigorous diffraction theory to design highly efficient and compact array generators is also discussed.