Monochromator Bandpass Calculator

A diffraction-grating monochromator or spectrograph disperses light according to the grating equation mλ = 2d cos(DV/2) sin θ, where m is diffraction order, d is groove spacing, and DV is the fixed deviation angle between incident and diffracted beams. The reciprocal linear dispersion P = d cos β / (m × f) in nm/mm then converts between slit width and spectral bandpass, where f is the focal length. This calculator solves both instrument configurations. Monochromator mode computes incidence angle, diffraction angle, linear dispersion, spectral bandpass from slit width, and slit-limited resolving power. Spectrograph mode adds detector parameters — pixel size and array length — to compute slit-limited and detector-limited (Nyquist) resolution separately, identifying which is the effective bottleneck, and reports the total spectral range captured by the array. Inputs cover focal length, groove density (g/mm), diffraction order, wavelength, and deviation angle.