Spectrometers

Spectrometers are instruments that measure the spectral properties of light or other signals. They separate incident radiation into its component wavelengths and record the intensity of each wavelength, producing a spectrum usable for identification, analysis, or quantification of materials.

A typical spectrometer includes an input aperture, a dispersive element (such as a prism or diffraction grating) or an interferometer, a detector, and processing electronics. Light is dispersed by wavelength, detected, and converted into an electrical signal that is presented as intensity versus wavelength or frequency. Calibration with known reference lines is standard to ensure accurate measurements.

Major families include optical spectrometers, covering ultraviolet to infrared regions (UV–Vis, NIR, FTIR), and mass spectrometers, which separate ions by mass-to-charge ratio. Other variants include Raman, fluorescence, and emission spectrometers. Dispersive instruments use prisms or gratings; Fourier-transform spectrometers use interferometry to obtain spectra.

Applications span chemistry, materials science, astronomy, environmental monitoring, medicine, and industry. Key performance metrics are spectral resolution, wavelength range, sensitivity, dynamic range, and calibration accuracy. Operation often involves corrections for instrument response and mitigation of stray light and noise.

The concept dates to prism experiments in the 18th and 19th centuries, with modern spectrometers combining precise optics, advanced detectors, and digital processing to achieve fast, accurate spectra across broad ranges.