Compact UV femtosecond direct laser write interferometry

Continuous wave interference is commonly used to produce large periodic modifications, essential for applications like lithography. However, the multistep process to produce functional devices reduced manufacturing efficiency. On the other hand, the ultraviolet ultrashort pulse laser micromachining enables precise control and repeatability of the ablation crater. We have developed a novel high-efficiency optical setup combining high-precision ablation with large modification areas. Key achievements include perfect spatial-temporal overlap which is not achieved by the other spitting techniques and will be confirmed by numerical simulations. This setup utilizes the third harmonic of a Yb:KGW laser, achieving 343 nm wavelength pulses with a 200 fs duration. With a high incident angle, we have produced gratings with a period of 800 nm in a single shot. This novel setup demonstrates excellent efficiency and versatility in manufacturing gratings across various materials.