A particular class of Montgomery's self-imaging objects that we call continuously self-imaging gratings (CSIG's) is introduced. When they are illuminated by a plane wave, these objects produce a field whose intensity profile is a propagation- and wavelength-invariant biperiodic array of bright spots. The mathematical construction of these objects and their intrinsic properties are described. On a practical level, CSIG's are compact and achromatic nondiffracting array generators. We show that a good CSIG approximation can be realized by a two-level phase grating that is experimentally tested.
© 2001 Optical Society of America
(050.1950) Diffraction and gratings : Diffraction gratings
N. Guérineau, B. Harchaoui, J. Primot, and K. Heggarty, "Generation of achromatic and propagation-invariant spot arrays by use of continuously self-imaging gratings," Opt. Lett. 26, 411-413 (2001)