In a study published in Light: Science & Applications, a team of researchers led by LI Wenhao from the Changchun Institute of Optics, Fine Mechanics and Physics of the Chinese Academy of Sciences made an advancement in the fabrication of holographic diffraction gratings. They developed a large-aperture, high-precision grating using an innovative scanning interference field exposure technique.

Diffraction gratings are essential components in a wide range of applications, including laser modulation, spectral analysis, and precision displacement measurement. However, traditional fabrication methods have struggled to achieve large size and high precision simultaneously.

The researchers developed a new scanning interference field exposure system which overcomes these limitations by combining grating sensing and laser interferometry for precise displacement measurement, ensuring stability over long exposure times. The system also employs a dynamic phase-locking model to compensate for phase errors in real time, significantly improving the quality of the interference fringes. 

By controlling the direction, period, and phase nonlinearity of the fringes, the researchers achieved a grating with a wavefront gradient of 16.444 nm/cm, making it suitable for demanding applications such as chirped pulse amplification systems and high-energy lasers.

By integrating high-precision displacement measurement, real-time phase error compensation, and advanced control of interference fringes, the researchers enabled the production of seamless, high-quality gratings. They created a 1500 mm × 420 mm grating with an exceptionally low wavefront aberration of 0.327λ at 632.8 nm, setting a new standard in grating technology.

This study not only advances the field of grating fabrication but also opens up new possibilities for applications in spectroscopy, laser systems, and ultra-high-precision displacement measurement.