Where are diffraction gratings used in applications? Diffraction gratings are commonly used for spectroscopic dispersion and analysis of light. (credit a: modification of work by 'Opals-On-Black'/Flickr credit b: modification of work by “whologwhy”/Flickr) Applications of Diffraction Gratings What remains are only the principal maxima, now very bright and very narrow ( Figure 4.12).įigure 4.15 (a) This Australian opal and (b) butterfly wings have rows of reflectors that act like reflection gratings, reflecting different colors at different angles. Furthermore, because the intensity of the secondary maxima is proportional to 1 / N 2 1 / N 2, it approaches zero so that the secondary maxima are no longer seen. This makes the spacing between the fringes, and therefore the width of the maxima, infinitesimally small. We can see there will be an infinite number of secondary maxima that appear, and an infinite number of dark fringes between them. Recall that N – 2 N – 2 secondary maxima appear between the principal maxima. The analysis of multi-slit interference in Interference allows us to consider what happens when the number of slits N approaches infinity. Diffraction Gratings: An Infinite Number of Slits The key optical element is called a diffraction grating, an important tool in optical analysis. However, most modern-day applications of slit interference use not just two slits but many, approaching infinity for practical purposes. Discuss the pattern obtained from diffraction gratingsĪnalyzing the interference of light passing through two slits lays out the theoretical framework of interference and gives us a historical insight into Thomas Young’s experiments.By the end of this section, you will be able to:

Grating equation