Rapid, automated, quality control of diffraction grating efficiency

A diffraction grating is found at the heart of every modern spectrophotometer and yet, despite being used for over 60 years, a practical and efficient characterization tool has proven to be elusive. Part of the challenge can be attributed to the unique angular dependent geometry, or off axis dispersion, of gratings. Here we demonstrate automated grating efficiency measurements of four reflection gratings (300, 1200, 1800 and 3600 grooves per mm). Total measurement time was less than 2 hrs at a maximum of 161 wavelengths per grating. This approach can reduce test times or assist expand quality assurance, or design verification, programs. Automated measurements are performed in hours demonstrating efficiency and ease-of-use advantages when compared to equivalent manually operated systems.