Wide-angle beam steering
Wide-angle beam steering using two or more variable lenses to form a small-angle beam steering element, along with a numerical aperture converter and a wide-angle lens. The small-angle beam steering element might comprise either one- or two-dimensional beam steering with tunable liquid lenses.
1. Apparatus for wide-angle beam steering of an input beam comprising:
a small-angle beam steering element for steering the input beam to form a small-angle steered beam;
a numerical aperture converter for spreading the small-angle steered beam; and
a wide-angle optical element for increasing a scanned angle of the spread beam up to at least about +/−75°;
wherein the small-angle beam steering element is configured to compensate for divergence changes cause by the wide-angle element, thereby controlling the divergence of the beam.
2. The apparatus of claim 1 wherein the small-angle beam steering element comprises a first variable lens configured to be centered on the input beam and a second variable lens configured to be decentered relative to the input beam, thereby scanning the beam, and wherein the first tunable lens is configured to compensate for variable divergence of the second variable lens.
3. The apparatus of claim 2 wherein the first variable lens and the second variable lens each comprise one of the following:
tunable pressure-driven liquid lens
tunable electrowetting liquid lens
tunable electrowetting liquid prism.
4. The apparatus of claim 2 , further comprising:
a third variable lens configured to be decentered relative to the input beam and relative to the second variable liquid lens, thereby scanning the beam in a second dimension; and
wherein the first variable lens further compensates for variable divergence of the third variable lens.
5. The apparatus of claim 4 wherein the first variable lens, the second variable lens, and the third variable lens each comprise one of the following:
tunable pressure-driven liquid lens
tunable electrowetting liquid lens
tunable electrowetting liquid prism.
6. The apparatus of claim 2 wherein the first variable lens and the second variable lens each comprise an electro-wetting liquid lens operating in resonant mode and wherein the second variable lens is driven at the same resonant frequency as the first variable lens, but at a 180-degree phase shift.
7. The apparatus of claim 6 further comprising a third variable lens and a fourth variable lens, wherein the third variable lens is on the beam axis and the fourth variable lens is off the beam axis and off the axis of the second variable lens, and wherein the third variable lens is configured to compensate for divergence of the fourth variable lens.
8. The apparatus of claim 1 wherein the numerical aperture converter includes one of the following:
a diffuser;
a microlens array;
a fiber face plate.
9. The apparatus of claim 1 wherein the small-angle beam steering element includes mechanical elements.
10. The apparatus of claim 9 wherein the small-angle beam steering element includes one of the following:
Risley prisms;
liquid-filled prisms with tilt plates.
11. The apparatus of claim 1 wherein the wide-angle optical element includes one of the following:
a wide-angle lens;
a fisheye lens;
a ball lens;
a combination of lenses.
12. A beam steering device comprising:
a first tunable liquid lens configured to be centered on the input beam for divergence control;
a second tunable liquid lens configured to be decentered relative to the input beam, thereby scanning the beam;
a numerical aperture converter; and
a wide-angle lens element for increasing a scanned angle of an output beam up to at least about +/−75°;
wherein the first tunable liquid lens is configured to compensate for a focal change caused by the second tunable liquid lens, resulting in a compensated beam; and
wherein the numerical aperture converter is configured to spread the compensated beam.
13. The apparatus of claim 12 wherein the numerical aperture converter includes one of the following:
a diffuser;
a microlens array;
a fiber face plate.
14. The apparatus of claim 12 wherein the wide-angle lens element includes one of the following:
a fisheye lens;
a ball lens;
a wide-angle lens;
a combination of lenses.
15. The apparatus of claim 12 , further comprising:
a third tunable liquid lens configured to be decentered relative to the input beam and relative to the second tunable liquid lens, thereby scanning the beam in a second dimension; and
wherein the first tunable lens further compensates for the focal change caused by the third tunable liquid lens.
16. A small-angle beam steering device for steering an input beam comprising:
a first tunable liquid lens configured to be centered on the input beam; and
a second tunable liquid lens configured to be decentered relative to the input beam, thereby scanning the beam;
wherein the first lens is configured to compensate for a focal change caused by the second tunable liquid lens;
and wherein the first lens is configured to compensate for divergence changes cause by the wide-angle element, thereby controlling the divergence of the beam.
17. The device of claim 16 further comprising:
a third tunable liquid lens configured to be decentered relative to the input beam and relative to the second tunable liquid lens, thereby scanning the beam in a second dimension.
18. The device of claim 17 wherein the tunable liquid lenses each comprise one of the following:
tunable pressure-driven liquid lens
tunable electrowetting liquid lens
tunable electrowetting liquid prism.
19. The device of claim 16 wherein the tunable liquid lenses each comprise one of the following:
tunable pressure-driven liquid lens
tunable electrowetting liquid lens
tunable electrowetting liquid prism.