Configuration and Optimization of Grating Systems in Littrow Configuration

"Littrow configuration” is the name given to those optical systems containing a reflective grating in which the orientation of the grating is such that the working order (most often the first diffraction order) travels back along the direction of the incident beam. This can be useful for various different applications, for example, in the context of laser resonators, where the grating can act as one of the mirrors of the resonator, or in monochromators and spectrometers.

In this week’s newsletter, we present two examples related to gratings in Littrow configuration. In the first, we demonstrate how to employ the Parameter Coupling tool in VirtualLab Fusion to ensure that the Littrow condition is fulfilled, by automatically adjusting the orientation of the grating, and the orientation and position of the detectors according to the wavelength and grating period. In the second example, we go over the optimization of a grating intended for use under Littrow configuration, where the goal is to design the grating structure so as to minimize its polarization effects.