Non-Uniform Diffraction Pattern of Grating Experiments---Rotating Grating Around Three Axes (3)

The orientation-dependence of the interference/diffraction patterns of the 1D-double slit, 2D- cross-double slit, 1D-grating and 2D-cross-grating experiments have been studied experimentally and theoretically. The universal phenomena of the curved, expanded, inclined and mirror-symmetric pattens were reported. However, the above experiments were limited to certain orientations, namely rotating the diaphragm/grating around either one axis or two axes. Here we show that, for certain orientations by rotating the grating around 3 axes, the spacings between adjacent diffraction orders are non-uniform. Namely, from “one end” of the pattern to “other end”, the spacings between adjacent diffraction orders gradually increase. This extraordinary phenomenon challenges the existing theories.

The above observed phenomena provide the comprehensive phenomena to theoretical study of the grating experiments. We suggest that the complete mathematical model should contain three rotation angles as parameters and should be able to describe the phenomena of the non-uniform-spacing, curved, expanded, inclined and mirror-symmetric diffraction patterns consistently.