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False color echelle spectrum with horizontal lines in different colors representing different wavelengths.

Echelle spectrometer

With a comparatively high light throughput and very high spectral resolution (λ/∆λFWHM), echelle grating-based spectrometers are among the most widely used optical measuring devices for a wide range of applications.

  • High-resolution echelle spectrographs with a large, simultaneously detectable wavelength range for atomic spectroscopy
  • High-resolution echelle monochromators for spectral measurement of narrow-band emission and absorption lines

2D spectra with Echelle spectrographs

Echelle spectrographs have an optical reflection echelle grating (French échelle: ladder, rung, step) that gives them their name. Incident light is split at the edges of these so-called blazed gratings with a sawtooth-like profile into specific, usually high diffraction orders. Depending on the specific application, the blaze angle of the grating used is designed to maximize the diffraction intensity in a desired diffraction order for a specific wavelength (blaze wavelength) (blazing). In order to separate the overlapping diffraction orders from each other depending on wavelength, the echelle grating in an echelle spectrograph is combined with a second, perpendicularly aligned cross-dispersive element, e.g. a prism. This results in a two-dimensional spectrum that can be detected with a suitable area detector.

Echelle monochromator in Littrow arrangement

With echelle monochromators in a Littrow arrangement, the blaze angle of the reflection grating is designed so that the diffracted beam is reflected back in the direction of the incident beam. As the angle of incidence and the angle of reflection are the same, this results in excellent imaging quality with maximum resolution.

Wide range of applications

LTB Lasertechnik Berlin offers various spectrometer models with patented optical design with different echelle grating and echelle grating/prism combinations, which are individually adapted to the specific application. This enables a wide range of products from compact high-resolution wide-range (double) echelle spectrographs of the ARYELLE series to high-resolution echelle monochromators of the DEMON and ELIAS series in Littrow arrangement for the spectral measurement of narrow-band emission and absorption lines.