NOVELTY - A diffractive photo-mask (101) comprises body element (104); interference/image-forming hologram gratings (102) located on or in the body element and configured to diffract light beam to produce functional element surrounded by high-spatial-frequency periodic optical-intensity distribution (121) at a substrate plane (110), when light beam is incident upon photo-mask; and zero-order beam blocking element (103) configured to block zero-order diffracted beams when the light beam is incident upon the diffractive photo-mask.    USE - As diffractive photo-mask for fabricating a high-spatial frequency periodic structure (claimed); in microelectronics, photonic crystal circuits, and numerous other structures; for manufacturing semiconductor devices used in cell phones, the internet, flat-panel televisions, flash memory chips, global positioning system devices, and solar cells; in the fields of biomedicine, transportation, communications, entertainment, defense, environmental monitoring, and homeland security; and in the primary fields of micro- and nano-electronic integrated circuits, photonic crystal devices, metamaterial devices, biomedical structures, subwavelength structures, and optical trapping.    ADVANTAGE - The diffractive photo-masks produce functional-element optical-intensity distribution when beams of light are directed incident to the photo-masks. The diffractive photo-mask can overcome the problems of prior art by having all of the mask information contained within the interference/image-forming hologram grating at the top of the photo-mask and/or within the body of the photo-mask. When a pattern mask is present, the projected image of the mask features effectively block the multiple interfering beams, thereby eliminating or altering selected portions of the periodic-optical-intensity distribution. The diffractive photo-mask can enable the single-exposure formation of non-periodic functional elements within a periodic lattice, without the need for complicated mask-alignment procedures. As such, the proposed photo-mask represents a highly efficient way of producing the complex patterns needed for microelectronics, photonic crystal circuits, and numerous other structures. The MBIL-defined lattice can determine the high-spatial-frequency periodic elements within the resulting exposed pattern. While the non-periodic functional elements can also be of high spatial frequency, the overall high-spatial-frequency imaging requirements are significantly reduced when compared to traditional projection lithography alone. The photo-mask enables wafer-scale-size manufacturing of critically important devices and structures in microelectronic fields. The photo-mask is unique in that it produces, by diffraction and interference, an image of the non-periodic functional elements integrated within a periodic lattice in a single exposure, without the need for complex alignment procedures. The apparatus allows for before photo-mask exposure monitoring, during photo-mask exposure monitoring of beams, and during photo-mask exposure monitoring of the mask pattern alignment.    DETAILED DESCRIPTION - A diffractive photo-mask (101) comprises a body element (104); interference/image-forming hologram gratings (102) located on or in the body element and configured to diffract a light beam to produce at least one functional element surrounded by a high-spatial-frequency periodic optical-intensity distribution (121) at a substrate plane (110), when the light beam is incident upon the diffractive photo-mask; and a zero-order beam blocking element (103) configured to block zero-order diffracted beams when the light beam is incident upon the diffractive photo-mask. The diffractive photo-mask is located proximate to a surface of a photosensitive material. The diffractive photo-mask further comprises a transparent material configured to place the diffractive photo-mask in physical contact with a photosensitive material at the substrate plane. The interference/image-forming hologram gratings comprise at least one high-efficiency volume grating; or comprise at least one material having an index of refraction that is different than an index of refraction of the body element. INDEPENDENT CLAIMS are included for the following:    (1) a method of fabricating a high-spatial frequency periodic structure involving: directing a light beam to be incident upon diffractive photo-mask, such that the diffractive photo-mask diffracts the light beam to produce at least one functional element surrounded by a high-spatial-frequency periodic optical-intensity distribution at a substrate plane; and    (2) a method of fabricating diffractive photo-mask, involving: transmitting a zero-order reference light beam that interferes with interference/image-forming light beams to interferometrically record interference/image-forming hologram gratings in a photo-mask recording material. The method of fabricating a diffractive photo-mask further involves monitoring and adjusting an alignment of a functional-element image. The interference/image-forming hologram gratings are formed by a scanned writing method.    DESCRIPTION OF DRAWING(S) - The figure shows schematic view of diffractive photo-mask.    Diffractive photo-mask system (100)    Diffractive photo-mask (101)    Interference/image-forming hologram grating (102)    Zero-order beam-blocking element (103)    Body element (104)    Substrate plane (110)    Substrate (120)    High-spatial-frequency periodic optical-intensity distribution (121)