Littrow Configuration for Blazed Gratings

Littrow configuration is the chosen denomination for a very commonly used way of orientating a blazed grating in monochromators, spectrometers & resonators, with the aim of obtaining maximum efficiency for the order with a diffraction angle equal to the angle of incidence. Needless to say, this type of system is extremely sensitive to the positions of the different elements, with the additional caveat that these optimal positions depend strongly on both the wavelength, and the period of the grating. We offer here an optical setup configured according to Littrow, which furthermore, via some programming, maintains those optimal positions even under a change of wavelength or grating period.