The collimated optical beam in a grating spectrometer may be circular or elliptical in cross section, so that different parts of the beam illuminate different numbers of grooves on the grating. Here we estimate the consequent loss in spectral resolution relative to that obtained with a beam that illuminates a fixed number of grooves. The effect reduces the intrinsic resolving power of the spectrometer by ~15%, exclusive of other contributions such as finite entrance-slit width.
© 2000 Optical Society of America
Edwin F. Erickson and David Rabanus, "Beam Shape Effects on Grating Spectrometer Resolution," Appl. Opt. 39, 4486-4489 (2000)