Abstract: The invention concerns a method of manufacturing a modulated optically diffractive grating and a corresponding grating. The method comprises providing a substrate and manufacturing a plurality of temporary elements onto the substrate, the temporary elements being arranged in a periodic pattern comprising at least two periods having different element characteristics. Next, a first deposition layer is deposited so as to at least partially cover the temporary elements with the first deposition layer and the temporary elements are removed from the substrate in order to form onto the substrate a modulated diffractive grating of first grating elements made of the first deposition layer, the pattern comprising within each period a plurality of first grating elements and one more gaps between the first grating elements. The invention allows for producing high-quality gratings with locally varying diffraction efficiency.

Abstract: The invention concerns a method of manufacturing a height-modulated optically diffractive grating. The method comprises providing a substrate and manufacturing a plurality of temporary elements of first material onto the substrate, the elements being separated by gaps and arranged as a periodic structure comprising at least two periods having different element heights. A coating layer of second material is deposited on the plurality of temporary elements such that the coating layer fills said gaps and covers said temporary elements. Then, a uniform layer of the second material is removed in order to expose said temporary elements and the first material is removed in order to form a height modulated pattern of the second material onto the substrate as the optically diffractive grating. The invention relaxes manufacturing constraints when manufacturing gratings with locally varying diffraction efficiency.

Abstract: The invention relates to a method of fabricating a master plate for producing diffractive structures and a master plate obtainable therewith. The method comprises providing a substrate having a periodic surface profile, filling the surface profile uniformly at least partly with filling material, and partially removing the filling material in order to produce a master plate having a periodic height-modulated surface profile formed by said substrate and said filling material. The invention allows for producing master plates capable of further producing gratings with variable diffraction efficiency.

Abstract: The invention relates to a method of manufacturing a diffractive grating. The method comprises providing a first substrate and manufacturing onto the first substrate a first surface profile using temporary grating material. Next, the first surface profile is covered entirely by a layer of final grating material and a second substrate is bonded onto the final grating material. Finally, the first substrate and the temporary grating material are removed for producing on the final grating material a second surface profile, which is a negative of the first surface profile. The invention allows for conveniently producing high quality gratings using e.g. inorganic materials and height and/or fill factor modulation for diffraction efficiency control.

Abstract: The invention relates to a diffractive optical grating and applications thereof. The grating comprises a first zone and a second zone each having a two-dimensionally periodic grating structure having a first period (dx) in a first direction, the first period being chosen to allow for diffraction of selected wavelengths of visible light along the first direction, and a second period (dy) in a second direction different from the first direction, the second period (dy) being short enough to prevent diffraction of said selected wavelengths along the second direction. According to the invention, the grating structures in the first zone and in the second zone have different modulation characteristics in said second direction for producing different diffraction efficiencies for the first and second zones. The invention provides a new design parameter, sub-wavelength modulation, for assisting in local adjustment of diffraction efficiency of gratings in particular in display applications.

Abstract: The invention relates to a method of manufacturing a diffractive grating. The method comprises providing a first substrate and manufacturing onto the first substrate a first surface profile using temporary grating material. Next, the first surface profile is covered entirely by a layer of final grating material and a second substrate is bonded onto the final grating material. Finally, the first substrate and the temporary grating material are removed for producing on the final grating material a second surface profile, which is a negative of the first surface profile. The invention allows for conveniently producing high quality gratings using e.g. inorganic materials and height and/or fill factor modulation for diffraction efficiency control.

Abstract: The invention concerns a method of manufacturing a height-modulated optically diffractive grating. The method comprises providing a substrate and manufacturing a plurality of temporary elements of first material onto the substrate, the elements being separated by gaps and arranged as a periodic structure comprising at least two periods having different element heights. A coating layer of second material is deposited on the plurality of temporary elements such that the coating layer fills said gaps and covers said temporary elements. Then, a uniform layer of the second material is removed in order to expose said temporary elements and the first material is removed in order to form a height modulated pattern of the second material onto the substrate as the optically diffractive grating. The invention relaxes manufacturing constraints when manufacturing gratings with locally varying diffraction efficiency.

Abstract: The invention concerns a method of manufacturing a master plate for fabrication of diffractive structures, and a corresponding master plate. The method comprises providing a substrate comprising a stack of selective etch layers and providing an etch mask layer on the substrate. Further, the method comprises etching the substrate in a multi-step etching process by exposing the substrate piecewise at different mask zones of the mask layer and using said selective etch layers to produce to the substrate a height-modulated surface profile defined by the mask zones in lateral dimensions and by said stack in height dimension of the substrate, and, finally, providing a height-modulated master grating onto the surface profile, the height modulation of the master grating being at least partly defined by said surface profile of the substrate.

Abstract: The invention relates to a selective diffractive grating and applications thereof. The grating comprised in a periodic alternating pattern first material having a first dispersion curve (n1), and second material having a second dispersion curve (n2) different from the first dispersion curve (n1). According to the invention, the first and second dispersion curves (n?i, n 2) intersect each other at two or more different wavelengths (?1 ?2).

Abstract: The invention relates to a diffractive optical grating and applications thereof. The grating comprises a first zone and a second zone each having a two-dimensionally periodic grating structure having a first period (dx) in a first direction, the first period being chosen to allow for diffraction of selected wavelengths of visible light along the first direction, and a second period (dy) in a second direction different from the first direction, the second period (dy) being short enough to prevent diffraction of said selected wavelengths along the second direction. According to the invention, the grating structures in the first zone and in the second zone have different modulation characteristics in said second direction for producing different diffraction efficiencies for the first and second zones. The invention provides a new design parameter, sub-wavelength modulation, for assisting in local adjustment of diffraction efficiency of gratings in particular in display applications.

Abstract: The invention relates to a method of fabricating a master plate for producing diffractive structures and a master plate obtainable therewith. The method comprises providing a substrate having a periodic surface profile, filling the surface profile uniformly at least partly with filling material, and partially removing the filling material in order to produce a master plate having a periodic height-modulated surface profile formed by said substrate and said filling material. The invention allows for producing master plates capable of further producing gratings with variable diffraction efficiency.

Abstract: The invention concerns a method of manufacturing a modulated optically diffractive grating and a corresponding grating. The method comprises providing a substrate and manufacturing a plurality of temporary elements onto the substrate, the temporary elements being arranged in a periodic pattern comprising at least two periods having different element characteristics. Next, a first deposition layer is deposited so as to at least partially cover the temporary elements with the first deposition layer and the temporary elements are removed from the substrate in order to form onto the substrate a modulated diffractive grating of first grating elements made of the first deposition layer, the pattern comprising within each period a plurality of first grating elements and one more gaps between the first grating elements. The invention allows for producing high-quality gratings with locally varying diffraction efficiency.