Concave Gratings

Concave Gratings

Tabs

Overview

Stigmatic imaging of spectra by using an aberration-corrected concave diffraction grating

The variable spacing and curved groove ruling technology, developed solely by Hitachi, eliminates the aberrations inherent to the conventional concave diffraction gratings. This greatly enhances the spectral image focusing properties of concave gratings. The Hitachi aberration corrected concave diffraction gratings include high resolution, reduced astigmatism, compact size, etc., which can be selected in accordance with the function of the equipment to which they are applied.

Line Spectra Graph

Mercury line spectra

The conventional concave grating images the spectra emitted from a pinhole into vertical straight lines, while the newly developed aberration-corrected concave grating images the spectrum in the form of a point.

Graph

Abberation correction by using the concave diffraction grating with varied-space grooves.

Graph Abberation correction by using the concave diffraction grating with curved grooves.
Graph

Conventional (equally-spaced, straight grooves) concave diffraction grating.

 

Reference

T. Harada and T. Kita, ”Mechanically ruled aberration-corrected concave gratings”, Appl. Opt. 19, 3987-3993(1980).