Diffraction and interference describe effects unlike what geometrical optics would predict: the edges of shadows are not quite sharp; the beam passed by a slit is not a narrow rectangle. Diffraction patterns carry information about the spacing and location of the elements in the diffraction grating that produced them. Conversely, if we know the structure of the grating, we can deduce properties about the incident light, in particular its wavelength. This will be our task, in this first optics lab exercise.
The analysis of diffraction patterns is used extensively in the sciences to provide information about the microscopic structure of molecules, atoms, and nuclei. In addition to various forms of light (gamma rays, x-rays, visible light, infra-red, radio waves), even high-energy atomic and sub-atomic particles (electrons, protons, and neutrons) can be used in diffraction studies. If one wants to know something about the wavelengths that make up a particular yep of radiation (I. . , the spectrum of radiation), one could use an object such as simple diffraction parallel-slit grating in the form of a spectrometer. For example, molecules, atoms, and nuclei typically radiate or scatter radiation that corresponds to discrete frequencies and hence discrete wavelengths, k. Knowing the spectrum (the intensity and wavelengths) of these radiations can tell us a lot about the molecule, atom, and nucleus under study.
Since diffraction-grating spectrometers and other types of radiation spectrometers are widely used in all sciences you should be familiar with the basic physics of such device What does diffraction look like? When light diffracts off of the edge of an object, it creates a pattern of light referred to as a diffraction pattern. If a monochromatic light source, such as a laser, is used to observe diffraction, below are some examples of diffraction patterns that are created by certain objects: