Automatic control method of spherical wave exposure interference field based on the Moiré alignment principle

Area of Science:

• Optics
• Optical Engineering
• Spectroscopy

Background:

• Aberration-corrected gratings are crucial for spectral analysis due to their optical properties.
• Phase distribution errors in exposure interference fields limit the groove density accuracy of gratings, hindering high-precision spectral instruments.

Purpose of the Study:

• To establish an error model for spherical wave exposure interference fields.
• To develop an automated method for controlling exposure interference fields to enhance grating groove density accuracy.

Main Methods:

• Developed an error model linking phase distribution error to recording parameter errors.
• Proposed a Moiré alignment principle for automatic phase measurement and recording parameter calculation.
• Implemented a feedback loop for automatic calibration and compensation of the interference field.

Main Results:

• Reduced the average relative error of grating groove density by two orders of magnitude compared to traditional methods.
• Significantly enhanced the control accuracy of the spherical wave exposure interference field.
• Improved the groove density distribution accuracy of aberration-corrected gratings.

Conclusions:

• The developed Moiré alignment method offers superior control over spherical wave exposure interference fields.
• This advancement supports the production of high-accuracy aberration-corrected gratings essential for advanced spectral analysis.
• The automated calibration method addresses key limitations in current grating fabrication processes.