Volume holographic optical elements with expanded angular acceptance

An apparatus comprising:

• an optical element characterized by a total range of acceptance angles for incident light, the optical element comprising:
• a first diffraction grating characterized by a first diffraction efficiency and a first range of acceptance angles;
• and
• a second diffraction grating characterized by a second diffraction efficiency and a second range of acceptance angles,
• wherein:
• the first diffraction grating and the second diffraction grating are arranged according to an overlapping arrangement,
• the first range and the second range are offset relative to each other by an offset angle,
• the total range is formed by at least the first range and the second range, and
• at a first incidence angle of the incident light, the first diffraction efficiency has a first value different from a second value of the second diffraction efficiency.

An augmented reality device comprising:

• an optical substrate;
• and
• an optical element coupled with the optical substrate and characterized by a total range of acceptance angles for light incident on the optical substrate, the optical element comprising:
• a first diffraction grating characterized by a first diffraction efficiency and a first range of acceptance angles;
• and
• a second diffraction grating characterized by a second diffraction efficiency and a second range of acceptance angles,
• wherein:
• the first diffraction grating and the second diffraction grating are arranged according to an overlapping arrangement,
• the first range and the second range are offset relative to each other by an offset angle,
• the total range is formed by at least the first range and the second range, and
• at a first incidence angle of the light, the first diffraction efficiency has a first value different from a second value of the second diffraction efficiency.

A system comprising:

• an optical element coupled with an optical substrate and characterized by a total range of acceptance angles for incident light, the optical element comprising:
• a first diffraction grating characterized by a first diffraction efficiency and a first range of acceptance angles;
• and
• a second diffraction grating characterized by a second diffraction efficiency and a second range of acceptance angles,
• wherein:
• the first diffraction grating and the second diffraction grating are arranged according to an overlapping arrangement,
• the first range and the second range are offset relative to each other by an offset angle,
• the total range is formed by at least the first range and the second range, and
• at a first incidence angle of the incident light, the first diffraction efficiency has a first value different from a second value of the second diffraction efficiency.