Single-slit diffraction pattern as wavelength varies, animation
Animation of a single-slit diffraction experiment, showing the wavefront before it passes through the aperture and the resulting wave pattern behind the aperture as a density distribution. It also shows the corresponding light intensity distribution on a screen while the wavelength of the incident light periodically changes. Single-slit diffraction creates a central bright fringe surrounded by alternating dark and bright fringes. The intensity of these fringes gradually decreases as the angle increases. When the wavelength of the light passing through the slit increases (which can be visualised as a change in light colour from blue to red), the diffraction pattern becomes more spread out; this causes both the central maximum and higher-order fringes to widen. Conversely, if the wavelength decreases, the pattern contracts, making the central maximum and fringes narrower. This phenomenon occurs because the diffraction angle is directly proportional to the wavelength, thereby affecting the overall spread of the pattern.