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A polychromator (from Greek : poly = much + chromos = color) is a monochromator in which there is no gap in the plane of the exit slit: in this way the entire spectrum can be viewed spatially fanned out at the same time. If a linear diode array detector ( PDA ) is used instead of the exit gap , the entire spectrum can be recorded simultaneously.

The result is an Optical Multichannel Analyzer ( OMA ) or Multi Channel Spectrometer ( MCS ) with which the spectrum to be examined can be recorded simultaneously (at the same time, in parallel). This represents a significant gain in the system compared to the conventional monochromator , in which the wavelengths have to be scanned one after the other . Modern multi-channel spectrometers can very quickly transfer a complete spectrum (e.g. in the visible spectral range) to the evaluation electronics.

Typical measurement times today are a few milliseconds with resolutions of 2048 pixels / spectrum.

Polychromators thus form the basis for industrial online applications of spectroscopic measurement processes. In the past, precise and fast receiver components were not available and spectroscopic processes in quality control, emission measurement, etc. were time-consuming carried out in the laboratory .

Other advantages of polychromators include:

  • low number of optical components and thus a reasonable manufacturing effort
  • no mechanically moving parts (little or no wear, even with continuous operation)
  • mostly permanently adjusted and mechanically fixed (maintenance-free)