An important part of the study of light has been the ability to disperse light, splitting it into a band of component colors called a spectrum. By doing so, scientists are able to examine the bright and dark emission and absorption lines that cross the spectrum, each one indicating the presence of an element. Early physicists such as Isaac Newton (1642-1727) used prisms to disperse light; later, beams of light were passed through a narrow slit, bending them slightly to produce a spectrum. Today, the most widely used instrument for obtaining the spectra of light is the diffraction grating.

Very crude diffraction gratings were used by American astronomer David Rittenhouse (1732-1796) and English physician and physicist Thomas Young (1773-1829); however, the first person to take an analytical approach toward the construction of gratings was the German optician Joseph von Fraunhofer, and it is he who is...