Variable shear with volume holograms

A display system, comprising:

• a waveguide;
• a light source configured to introduce light into the waveguide at a controllable light input angle;
• an optical device configured to outcouple from the waveguide light received from within the waveguide that meets an angular condition, the optical device comprising:
• a first rigid substrate;
• a flexible holographic optical element;
• a transparent flexible material having a variable shear transmission property across an in-plane direction of the flexible holographic optical element;
• and
• a second rigid substrate, wherein the flexible holographic optical element and the transparent flexible material are located between the first and second rigid substrates;
• wherein
• the variable shear transmission property of the transparent flexible material transmits variable amounts of a shear force applied to the first or second rigid substrates across the in-plane direction of the flexible holographic optical element;
• a processor configured to control the light input angle and the shear force applied to the optical device to control a light output angle from the display system.

A method, comprising:

• determining a target exit pupil;
• applying variable shear force to a flexible holographic optical element based on the target exit pupil, the variable shear force applying a variable amount of shear force in an in-plane direction of the holographic optical element;
• inputting light from a light source into a waveguide at an input angle;
• and
• diffracting, via a hologram of the sheared flexible holographic optical element, light outcoupled from the waveguide toward the target exit pupil.