High-speed measurement method for diffraction efficiency of gratings in broad range wavelength based on AOTF

Area of Science:

• Optics and Photonics
• Materials Science
• Metrology

Background:

• Diffraction efficiency is crucial for grating performance evaluation.
• Traditional methods for measuring diffraction efficiency are time-consuming.
• Current fast techniques cover a limited wavelength range (550-750 nm).

Purpose of the Study:

• To develop a high-speed, wide-wavelength measurement method for diffraction efficiency.
• To improve the precision and reduce the measurement time for grating characterization.

Main Methods:

• Utilized an acousto-optic tunable filter (AOTF).
• Incorporated an integrating sphere and a concave mirror for efficient light collection and focusing.
• Developed a novel setup for rapid spectral scanning.

Main Results:

• Achieved measurement of diffraction efficiency curves in under one minute.
• Covered a broad wavelength range from 500 nm to 1000 nm.
• Demonstrated high accuracy with mean absolute error < 2% and repeatability error < 2% for gratings (300-1200 grooves/mm).

Conclusions:

• The proposed method offers a significant advancement in high-speed grating characterization.
• This technique enables rapid and precise evaluation of grating performance over an extended spectral range.
• The method is suitable for gratings with varying groove densities, enhancing its applicability.