An apparatus for generating stereoscopic images for virtual reality and / or augmented reality, comprising a display device characterized by being wearable by users, the display device further comprising: an eyepiece including a substrate (702, 802, 1002A, 1002B, 1102, 1704, 1804, 1904, 2004, 2104, 2202); an in-coupling optic element (712, 808, 1710, 1810, 1910, 2010, 2206) to transmit input light beams (710, 2214) into the substrate (702, 802, 1002A, 1002B, 1102, 1704, 1804, 1904, 2004, 2104, 2202); and a first layer of the substrate (702, 802, 1002A, 1002B, 1102, 1704, 1804, 1904, 2004, 2104, 2202) comprising first diffractive elements (704, 804, 904, 1004A, 1004B, 1104, 1402, 1504A, 1706, 1806, 1906, 2006, 2106) and second diffractive elements (706, 806, 906, 1006A, 1006B, 1106, 1404, 1506B, 1708, 1808, 1908, 2008, 2108) that are operatively coupled to the in-coupling optic element (712, 808, 1710, 1810, 1910, 2010, 2206) and are disposed on one or more sides of the substrate (702, 802, 1002A, 1002B, 1102, 1704, 1804, 1904, 2004, 2104, 2202), wherein the first diffractive elements (704, 804, 904, 1004A, 1004B, 1104, 1402, 1504A, 1706, 1806, 1906, 2006, 2106) and the second diffractive elements (706, 806, 906, 1006A, 1006B, 1106, 1404, 1506B, 1708, 1808, 1908, 2008, 2108) comprise linear diffractive elements (704, 804, 904, 1004A, 1004B, 1104, 1402, 1504A, 1706, 1806, 1906, 2006, 2106) as well as circular or radially symmetric diffractive elements, wherein the first diffractive elements (704, 804, 904, 1004A, 1004B, 1104, 1402, 1504A, 1706, 1806, 1906, 2006, 2106) and the second diffractive elements (706, 806, 906, 1006A, 1006B, 1106, 1404, 1506B, 1708, 1808, 1908, 2008, 2108) each include both surface-relief type diffractive elements and volumetric-phase type diffractive elements, wherein the first diffractive elements (704, 804, 904, 1004A, 1004B, 1104, 1402, 1504A, 1706, 1806, 1906, 2006, 2106) comprise orthogonal pupil expansion diffractive elements and are configured to deflect a first portion of the input light beams into first deflected light beams toward the second diffractive elements (706, 806, 906, 1006A, 1006B, 1106, 1404, 1506B, 1708, 1808, 1908, 2008, 2108), and wherein the second diffractive elements (706, 806, 906, 1006A, 1006B, 1106, 1404, 1506B, 1708, 1808, 1908, 2008, 2108) comprise exit pupil expansion diffractive elements and are configured to deflect a smaller portion of the first deflected light beams toward at least one eye of a user and to allow another portion of the first exit light beams to continue to propagate within the substrate (702, 802, 1002A, 1002B, 1102, 1704, 1804, 1904, 2004, 2104, 2202). an eyepiece including a substrate (702, 802, 1002A, 1002B, 1102, 1704, 1804, 1904, 2004, 2104, 2202); an in-coupling optic element (712, 808, 1710, 1810, 1910, 2010, 2206) to transmit input light beams (710, 2214) into the substrate (702, 802, 1002A, 1002B, 1102, 1704, 1804, 1904, 2004, 2104, 2202); and a first layer of the substrate (702, 802, 1002A, 1002B, 1102, 1704, 1804, 1904, 2004, 2104, 2202) comprising first diffractive elements (704, 804, 904, 1004A, 1004B, 1104, 1402, 1504A, 1706, 1806, 1906, 2006, 2106) and second diffractive elements (706, 806, 906, 1006A, 1006B, 1106, 1404, 1506B, 1708, 1808, 1908, 2008, 2108) that are operatively coupled to the in-coupling optic element (712, 808, 1710, 1810, 1910, 2010, 2206) and are disposed on one or more sides of the substrate (702, 802, 1002A, 1002B, 1102, 1704, 1804, 1904, 2004, 2104, 2202), wherein the first diffractive elements (704, 804, 904, 1004A, 1004B, 1104, 1402, 1504A, 1706, 1806, 1906, 2006, 2106) and the second diffractive elements (706, 806, 906, 1006A, 1006B, 1106, 1404, 1506B, 1708, 1808, 1908, 2008, 2108) comprise linear diffractive elements (704, 804, 904, 1004A, 1004B, 1104, 1402, 1504A, 1706, 1806, 1906, 2006, 2106) as well as circular or radially symmetric diffractive elements, wherein the first diffractive elements (704, 804, 904, 1004A, 1004B, 1104, 1402, 1504A, 1706, 1806, 1906, 2006, 2106) and the second diffractive elements (706, 806, 906, 1006A, 1006B, 1106, 1404, 1506B, 1708, 1808, 1908, 2008, 2108) each include both surface-relief type diffractive elements and volumetric-phase type diffractive elements, wherein the first diffractive elements (704, 804, 904, 1004A, 1004B, 1104, 1402, 1504A, 1706, 1806, 1906, 2006, 2106) comprise orthogonal pupil expansion diffractive elements and are configured to deflect a first portion of the input light beams into first deflected light beams toward the second diffractive elements (706, 806, 906, 1006A, 1006B, 1106, 1404, 1506B, 1708, 1808, 1908, 2008, 2108), and wherein the second diffractive elements (706, 806, 906, 1006A, 1006B, 1106, 1404, 1506B, 1708, 1808, 1908, 2008, 2108) comprise exit pupil expansion diffractive elements and are configured to deflect a smaller portion of the first deflected light beams toward at least one eye of a user and to allow another portion of the first exit light beams to continue to propagate within the substrate (702, 802, 1002A, 1002B, 1102, 1704, 1804, 1904, 2004, 2104, 2202).