Crespo Vázquez, DanielAlonso Fernández, JoséBernabeu Martínez, Eusebio2023-06-202023-06-202000-071. F. Talbot, “Facts relating to optical science. No. IV”, Philos. Mag. 9, 401–407 (1836). 2. E. Bar-Ziv, “Effect of diffraction on the moire image. I. Theory”, J. Opt. Soc. Am. A 2, 371–379 (1985). 3. E. Lau, “Beugungserscheinungen an Doppelrastern”, Ann. Phys. (Leipzig) 6, 417–423 (1948). 4. L. Liu, “Talbot and Lau effects on incident beams of arbitrary wavefront, and their use”, Appl. Opt. 28, 4668–4677 (1989). 5. F. Gori, “Lau effect and coherence theory”, Opt. Commun. 31, 4–8 (1979). 6. G. J. Swanson, E. N. Leith, “Analysis of the Lau effect and generalized grating imaging”, J. Opt. Soc. Am. A 2, 789–793 (1985). 7. E. N. Leith, R. Hershey, “Transfer functions and spatial filtering in grating interferometers”, Appl. Opt. 24, 237–239 (1985). 8. A. Olszak, L. Wronkowski, “Analysis of the Fresnel field of a double diffraction system in the case of two amplitude diffraction gratings under partially coherent illumination”, Opt. Eng. 36, 2149–2157 (1997). 9. E. Keren, O. Kafri, “Diffraction effects in moiré deflectometry”, J. Opt. Soc. Am. 2, 111–120 (1985). 10. G. J. Swanson, E. N. Leith, “Lau effect and grating imaging”, J. Opt. Soc. Am. 72, 552–555 (1982).0740-323210.1364/JOSAA.17.001231https://hdl.handle.net/20.500.14352/59239© Optical Society of America. This work was partially supported by the project Tecnologías Avanzadas de la Producción, TAP 98\0862, of the Comisión Interministerial de Ciencia Y Tecnología (CICYT).It is a well-known fact that one grating can act as an imaging element for another grating when the first is illuminated with an extended monochromatic light source. The conditions for image formation in such a system are studied when the finite size and position of the broad light source are considered. From the presented analysis, expressions for the location and the depth of focus of such images can be derived.engjournal articlehttp://dx.doi.org/10.1364/JOSAA.17.001231http://www.opticsinfobase.orgopen access535DiffractionÓptica (Física)2209.19 Óptica Física