Bi-Directional Waveguide Coupling

A method for holographic projection, wherein the method comprises:

• illuminating a spatial light modulator with a first optical element at a first angle of illumination to form a first wavefront;
• illuminating the spatial light modulator with a second optical element at a second angle of illumination to form a second wavefront;
• coupling the first wavefront into a waveguide at a first angle of incidence;
• coupling the second wavefront into the waveguide at a second angle of incidence, wherein the first angle of incidence is opposite in direction to the second angle of incidence;
• replicating the first wavefront along a first dimension of the waveguide in a first direction;
• and
• replicating the second wavefront along the first dimension of the waveguide in a second direction, the first direction being opposite to the second direction.

Tangible, non-transitory computer-readable media comprising program instructions, wherein the program instructions, when executed by one or more processors, cause a holographic projection system to perform functions comprising:

• illuminating a spatial light modulator with a first optical element at a first angle of illumination to form a first wavefront;
• illuminating the spatial light modulator with a second optical element at a second angle of illumination to form a second wavefront;
• coupling the first wavefront into a waveguide at a first angle of incidence;
• coupling the second wavefront into the waveguide at a second angle of incidence, wherein the first angle of incidence is opposite in direction to the second angle of incidence;
• replicating the first wavefront along a first dimension of the waveguide in a first direction;
• and
• replicating the second wavefront along the first dimension of the waveguide in a second direction, the first direction being opposite to the second direction.