spektroskop

A spektroskop is an optical instrument used to observe and analyze the spectral composition of light. It works by dispersing light into its component wavelengths and presenting a spectrum for examination. Light from a source passes through a slit, is directed onto a dispersive element such as a prism or a diffraction grating, and is then focused onto a viewing screen or recorded by a detector. Historically, photographic plates were used, while modern devices rely on detectors like CCDs or photomultiplier tubes.

Purpose and principles

A spectroscope enables identification of materials and analysis of their properties by examining emission or absorption lines in the spectrum. The position and intensity of spectral lines provide information about chemical composition, temperature, density, and, in some cases, motion through Doppler shifts. The instrument can be used to study both emission spectra (from excited sources) and absorption spectra (from light passing through a sample).

Types and capabilities

Dispersive spectroscopes use prisms or diffraction gratings to spread light into a spectrum. Spectrographs, often with long focal lengths or multiple gratings, aim for higher spectral resolution. Modern variants include echelle spectrographs for high-resolution work and Fourier-transform spectrometers for broad-band or precise measurements. In astronomy, spectrographs are used to determine stellar composition, velocities, and redshifts; in chemistry and materials science, they support qualitative and quantitative analysis.

Historical note

The solar spectrum’s dark Fraunhofer lines revealed a structured spectrum, leading to the realization that each element produces characteristic lines. Bunsen and Kirchhoff demonstrated that these lines can identify elements in unknown samples, founding modern spectroscopy.