For a reflection grating, this means that the diffracted beam is back-reflected into the direction of the incident beam The beams are perpendicular to the step and therefore parallel to the step normal. The Littrow configuration is a special geometry in which the blaze angle is chosen such that diffraction angle and incidence angle are identical. The direction in which maximum efficiency is achieved is called the blaze angle and is the third crucial characteristic of a blazed grating directly depending on blaze wavelength and diffraction order(from Wikipedia). Since this condition can only exactly be achieved for one wavelength, it is specified for which blaze wavelength the grating is optimized (or blazed). For this purpose, maximum optical power is concentrated in the desired diffraction order while the residual power in the other orders (particularly the zeroth) is minimized. It is optimized to achieve maximum grating efficiency in a given diffraction order. Trace thousands of rays in non sequential mode of Zemax OpticStudio only take few seconds.Ī blazed grating – also called echelette grating (from French échelle = ladder) – is a special type of diffraction grating. Rigorous Coupled Wave Analysis(RCWA) is implemented in the toolbox(based on GratingMaster engine, LightSoft LLC) which had been proved to be a very fast and accurate way to handle grating device. With this toolbox, we can not only design individual grating, but also can design systems including gratings in entire system level and could utilize almost all built in features of Zemax OpticStudio. Recently we extend the capability of our ARtrix grating toolbox as a plugin model of Zemax OpticStudio, so it can be used to design any arbitrary shape grating and nicely support for both sequential mode and non sequential mode of Zemax. Gratings that modulate the phase rather than the amplitude of the incident light are also produced, frequently using holography(from Wikipedia). Such gratings can be either transmissive or reflective. Because of this, gratings are commonly used in monochromators and spectrometers, recently they are introduced as coupling devices in AR/MR lightguide application like Microsoft’s HoloLens.įor practical applications, gratings generally have ridges or rulings on their surface rather than dark lines. The directions of these beams depend on the spacing of the grating and the wavelength of the light so that the grating acts as the dispersive element. In optics, a diffraction grating is an optical component with a periodic structure that splits and diffracts light into several beams travelling in different directions.
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