The diffraction of light by deep rectangular-groove transmission phase gratings is treated by solving Maxwell’s equations numerically. Results are given for the light diffracted into the zero order by gratings with grating constants <i>d</i> in the range λ < <i>d</i> < 5λ, aspect ratio <i>b</i> (= linewidth/<i>d</i>), 0 < <i>b</i> < 1, and grating depths <i>a</i> < 5λ, assuming a refractive index <i>n</i><sub>0</sub> = 1.5. Such gratings are used in practice as a dye-free replacement for color filters. They offer a new way of storing pictorial information in small format for read out in conventional projectors.
© 1978 Optical Society of AmericaPDF Article