Fabrication of 3D computer-generated hologram inside glass by femtosecond laser direct writing

The three-dimensional holography technique offers a powerful method for storing the depth information of objects, and it provides more realistic scene reconstruction compared with the two-dimensional case, so it is widely used in beam shaping, holographic display, and image encryption. However, the fabrication of holograms is currently limited to complex and time-consuming traditional nanofabrication techniques. Here, we demonstrate the fabrication of a hologram containing depth information inside glass using femtosecond laser direct writing. The whole process is simple and flexible because there is no complex operation like mask preparation. Then the reconstruction of the three-dimensional object is demonstrated and evaluated, and the experimental optimization as well as the limitations are also discussed.