Axial HoloTile: Extended depth-of-focus of dynamic holographic light projections

This publication extends the HoloTile framework to three dimensions, introducing the ability to generate arbitrary dynamic patterns composed of extended depth-of-field non-diffractive beamlets with theoretically 100% diffraction efficiency. In particular, we demonstrate experimentally the generation of speckle-reduced reconstruction patterns, consisting of spatially multiplexed extended Bessel-like beamlets, implemented on a phase-only spatial light modulator (SLM). Due to the inherent separation of the tiled subhologram and the point spread function shaping hologram in HoloTile, we show that the reconstruction amplitude can be expressed as a simple convolution of the contributions from the two holograms. This results in a discretely sampled reconstruction, with each spatial frequency component exhibiting long DoF with characteristic Bessel beam properties. This separation facilitates spatial and temporal multiplexing of both contributions, and allows for real-time dynamic patterning with extended DoF. Additionally, a geometric analysis is included, allowing for the direct calculation of the propagation characteristics of the beamlets.