It utilizes optical fibers to transmit light from a source to a spectrometer unit, where the light is dispersed into its component wavelengths and analyzed. Optical spectroscopy is a technique that is used to measure light intensity in the ultraviolet (UV), visible (VIS), near-infrared (NIR), and infrared (IR) range of the electromagnetic spectrum. Spectroscopic measurements are used in many different applications, such as color measurement. Internal structure of a grating spectrometer: Light comes from left side and diffracts on the upper middle reflective grating. The wavelength of light is then selected by the slit on the upper right corner. Spectrometers have a wide range of applications and uses. It keeps the signal quality high while making instrument designs way more flexible and compact. Because of this, we can now do spectroscopy.