Pattern projector
An optoelectronic apparatus includes a semiconductor substrate and multiple arrays of emitters disposed on the semiconductor substrate and configured to emit beams of optical radiation. An optical substrate is mounted over the semiconductor substrate. An optical metasurface disposed on the optical substrate includes multiple optical apertures. Each aperture is configured to receive, collimate and split the beams emitted by a respective array of the emitters into a respective group of collimated sub-beams, so as to direct the collimated sub-beams toward a target at different, respective angles to form a pattern of spots on the target.
1 . An optoelectronic apparatus, comprising:
a semiconductor substrate;
multiple arrays of emitters disposed on the semiconductor substrate and configured to emit beams of optical radiation;
an optical substrate mounted over the semiconductor substrate;
an optical metasurface disposed on the optical substrate and comprising multiple optical apertures, each aperture configured to receive, collimate and split the beams emitted by a respective array of the emitters into a respective group of collimated sub-beams, so as to direct the collimated sub-beams toward a target at different, respective angles to form a pattern of spots on the target; and
multiple lenses disposed between the semiconductor substrate and the optical substrate in alignment with the multiple arrays of emitters and configured to direct the beams emitted by each array onto a respective one of the multiple optical apertures.
2 . The apparatus according to claim 1 , wherein the multiple lenses comprise discrete individual lenses, which are respectively aligned with the multiple arrays of emitters.
3 . The apparatus according to claim 1 , wherein the multiple lenses are formed as a monolithic unit.
4 . The apparatus according to claim 1 , wherein the multiple lenses are configured as a compound lens.
5 . The apparatus according to claim 1 , and comprising one or more dies of semiconductor material, wherein the arrays of emitters are disposed on respective ones of the one or more dies, and the one or more dies are mounted on the semiconductor substrate.
6 . The apparatus according to claim 5 , wherein the optical metasurface is configured to project the collimated sub-beams so that the target is tiled by images of at least one of the one or more dies.
7 . The apparatus according to claim 5 , wherein the optical metasurface has a focal plane, and the one or more dies comprise:
at least one first die emitting first beams of the optical radiation at the focal plane, so as to form the pattern of spots on the target; and
at least one second die emitting second beams of the optical radiation at an emission plane that is displaced by a predetermined distance from the focal plane, so that the second beams illuminate the target with flood illumination.
8 . The apparatus according to claim 7 , wherein the at least one first die has a first thickness, and the at least one second die has a second thickness greater than the first thickness by the predetermined distance.
9 . The apparatus according to claim 7 , wherein the at least one second die is mounted on a pedestal, which elevates the emission plane of the at least one second die relative to the at least one first die by the predetermined distance.
10 . The apparatus according to claim 1 , and comprising:
one or more further arrays of emitters, which are disposed on the semiconductor substrate and are configured to emit further beams of optical radiation; and
a further optical metasurface, which is configured to receive and split the further beams into diverging sub-beams, and to direct the diverging sub-beams toward the target at different, respective angles to illuminate the target with flood illumination.
11 . The apparatus according to claim 10 , and comprising a controller, which is configured to actuate the apparatus so as to illuminate the target with either the pattern of spots or the flood illumination.
12 . The apparatus according to claim 1 , wherein the arrays of emitters are disposed on a back side of at least one semiconductor die, and the apparatus comprises microlenses formed on a front side of the at least one semiconductor die in alignment with the emitters and configured to direct the emitted beams toward the optical metasurface.
13 . The apparatus according to claim 12 , wherein each microlens comprises a tilted toroidal surface.
14 . The apparatus according to claim 1 , wherein the pattern of spots comprises multiple replicas of the multiple arrays of emitters, wherein the replicas are tiled across the target.
15 . The apparatus according to claim 1 , wherein the pattern of spots comprises multiple replicas of the multiple arrays of emitters, illuminating different, respective zones of the target.
16 . The apparatus according to claim 1 , wherein the emitters comprise vertical-cavity surface-emission lasers (VCSELs).
17 . The apparatus according to claim 1 , wherein the multiple arrays are disposed on the semiconductor substrate in a hexagonal pattern.
18 . The apparatus according to claim 1 , wherein the multiple arrays are disposed on the semiconductor substrate in a rectangular pattern.
19 . A method for optical projection, comprising:
mounting on a semiconductor substrate multiple arrays of emitters configured to emit beams of optical radiation;
mounting over the semiconductor substrate an optical substrate having an optical metasurface disposed thereon, the optical metasurface comprising multiple optical apertures, each aperture configured to receive, collimate and split the beams emitted by a respective array of the emitters into a respective group of collimated sub-beams, so as to direct the collimated sub-beams toward a target at different, respective angles to form a pattern of spots on the target; and
disposing multiple lenses between the semiconductor substrate and the optical substrate in alignment with the multiple arrays of emitters and configured to direct the beams emitted by each array onto a respective one of the optical apertures.