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Grating Diffraction Calculator

Calculate diffraction angles, angular dispersion, resolving power, and free spectral range for diffraction gratings using the grating equation.

Grating Parameters
Advanced Options
Primary Results
Groove Spacing (d)
1666.7 nm
Groove Spacing (d)
1.6667 μm
Diffraction Angle (β, m=1)
22.31°
Dispersion
Angular Dispersion
0.0372 °/nm
Angular Dispersion
0.6486 mrad/nm
Littrow & Free Spectral Range
Littrow Angle (θ_L, m=1)
10.94°
Free Spectral Range
632.8 nm
All Propagating Orders
Order (m)Angle β (°)
-2-49.41
-1-22.31
00
+122.31
+249.41
Abridged Optics — Grating Diffraction Calculator v1.0Calculations assume ideal grating behavior. Actual efficiency depends on groove profile, polarization, and coating.

All information, equations, and calculations have been compiled and verified to the best of our ability. For mission-critical applications, we recommend independent verification of all values. If you find an error, please let us know.