In {TAIL ~ diffraction}, {HEAD ~ light} acts as a wave, bending around an obstacle in its path, such as a grating 
In
In { TAIL ~ diffraction } , { HEAD ~ light } acts as a wave , bending around an obstacle in its path , such as a grating
REL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH