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Spectrometer Resolution Calculator

Calculate spectral resolution from grating, focal length, slit width, and detector parameters for Czerny-Turner spectrometers.

Spectral resolution is the minimum wavelength separation a spectrometer can distinguish as two separate lines. In a Czerny-Turner spectrometer — the most common laboratory design — resolution is set by the grating groove density, the focal length of the focusing mirror, the width of the entrance slit, and the pixel size of the detector array. This calculator applies the grating equation and slit-limited resolution formula to compute Δλ (minimum resolvable wavelength interval) and the wavelength at any given diffraction angle, helping with instrument selection and configuration for spectroscopy experiments.

Grating & Geometry
Slit & Detector
Diffraction Geometry
Incidence angle α
24.511°
Diffraction angle β
-5.489°
Dispersion
Angular dispersion
602.8µrad/nm
Linear dispersion
0.1507mm/nm
Reciprocal linear dispersion
6.636nm/mm
Dispersion per pixel
0.0929nm/pixel
Resolution
Slit-limited δλ
0.0664nm
Pixel-limited δλ
0.2787nm
Resolution factor (RF)
3.000
Effective δλ (pixel-limited)
0.2787nm
Resolving power R
1908.8
Coverage
Spectral coverage
190.3nm
Free spectral range
532.0nm

For the full treatment of spectrometer design — Czerny-Turner geometry, detector selection, SNR, stray light, and fiber coupling — see the Spectrometers comprehensive guide.

Abridged Optics — v1.0Grating equation solved numerically with included-angle constraint α = β + 2θ. Resolution factor interpolated from standard RF values. Assumes first-order unless specified.

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.