Acousto-optic device having wide diffraction angle, optical scanner, light modulator, and display apparatus using the acousto-optic device

An optical scanner, comprising:

• a first acousto-optic device configured to diffract and/or deflect light in a first direction;
• a second acousto-optic device configured to diffract and/or deflect light in a second direction that is perpendicular to the first direction;
• and
• a light-coupling device configured to make light incident to the first acousto-optic device,
• wherein each of the first and second acousto-optic devices comprises a core layer having a periodic photonic crystal structure in which unit cells of predetermined patterns are repeated, a first clad layer on a first surface of the core layer, the first clad layer having a refractive index that is different from a refractive index of the core layer, a second clad layer on a second surface of the core layer, the second surface being opposite the first surface, the second clad layer having a refractive index that is different from the refractive index of the core layer, and a sound wave generator configured to apply surface acoustic waves (SAW) to the core layer, the first clad layer, the second clad layer, or any combination thereof, and
• wherein the core layer, the first clad layer, the second clad layer, or any combination thereof to which the SAW are applied includes an acousto-optic material.

A two-dimensional (2D)/three-dimensional (3D) switchable image display apparatus, comprising:

• a display panel;
• and
• an acousto-optic device array on a front surface of the display panel, the acousto-optic device array being configured to diffract and/or deflect images displayed on the display panel, the acousto-optic device array comprising acousto-optic devices, each of the acousto-optic devices comprising a core layer having a periodic photonic crystal structure in which unit cells of predetermined patterns are repeated, a first clad layer on a first surface of the core layer, the first clad layer having a refractive index that is different from a refractive index of the core layer, a second clad layer on a second surface of the core layer, the second surface being opposite the first surface, the second clad layer having a refractive index that is different from the refractive index of the core layer, and a sound wave generator configured to apply surface acoustic waves (SAW) to the core layer, the first clad layer, the second clad layer, or any combination thereof,
• wherein the core layer, the first clad layer, the second clad layer, or any combination thereof to which the SAW are applied includes an acousto-optic material.

A holographic display apparatus, comprising:

• a light source configured to provide light;
• an acousto-optic device array comprising a plurality of acousto-optic devices, each of the acousto-optic devices being configured to diffract and/or deflect the light provided from the light source, each of the acousto-optic devices comprising a core layer having a periodic photonic crystal structure in which unit cells of predetermined patterns are repeated, a first clad layer on a first surface of the core layer, the first clad layer having a refractive index that is different from a refractive index of the core layer, a second clad layer on a second surface of the core layer, the second surface being opposite the first surface, the second clad layer having a refractive index that is different from the refractive index of the core layer, and a sound wave generator configured to apply surface acoustic waves (SAW) to the core layer, the first clad layer, the second clad layer, or any combination thereof;
• and
• a projection optical system configured to project the light diffracted by the acousto-optic device array,
• wherein the core layer, the first clad layer, the second clad layer, or any combination thereof to which the SAW are applied includes an acousto-optic material.

An acousto-optic device, comprising:

• a core layer including an acousto-optic material, the core layer having a periodic photonic crystal structure in which unit cells of predetermined patterns are repeated, the core layer being configured to generate a region at certain frequencies and wave vectors of lights around a photonic bandgap in which an angular distribution of a refractive index becomes flat;
• and
• a sound wave generator configured to provide surface acoustic waves (SAW) along the flat region of the angular distribution of the refractive index in the core layer,
• wherein incident light proceeding toward a vertex of the angular distribution of the refractive index is diffracted along the flat region of refractive index distribution toward an adjacent vertex.