First-order diffraction grating

Diffraction gratings produce spectra (fringes) on either side of a central maximum, separated by angles theta.

nl = d sinq ... where d is the grating line separation.

If the slits are cut into glass etc. at an angle (blazed), the light energy can be concentrated into one spectrum.

This blazed grating has just one intense first order spectrum. The grating operates approximately like a prism with exceptionally high dispersion.

First-order grating glasses, give a 3D appearance to some ordinary colored illustrations.

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