Polarization-selective varifocal liquid lens
A varifocal liquid lens includes a body filled with two different fluids separated by an interface of a variable curvature across a clear aperture of the varifocal liquid lens. At least one of the first or second fluids is birefringent, such that a refractive index difference between the first and second fluids and resulting optical power of the varifocal liquid lens is dependent on polarization of impinging light. At a first light polarization, the first and second fluids may be matched in refractive index, while at a second, orthogonal light polarization, the first and second fluids may be mismatched in refractive index, whereby the first interface between the first and second fluids may have a variable, non-zero optical power for the second polarization while having a substantially non-variable, zero optical power for the first polarization of light.
1. A varifocal liquid lens comprising a body filled with first and second fluids separated by a first interface therebetween, the first interface having a variable curvature across a clear aperture of the varifocal liquid lens;
wherein at least one of the first or second fluids is birefringent, such that a refractive index difference between the first and second fluids and resulting optical power of the varifocal liquid lens is polarization-dependent.
2. The varifocal liquid lens of claim 1 , wherein at a first polarization of light propagating through the clear aperture, the first and second fluids are matched in refractive index, while at a second, orthogonal polarization, the first and second fluids are mismatched in refractive index, whereby the first interface between the first and second fluids has a variable, non-zero optical power for the second polarization of light while having a substantially non-variable, zero optical power for the first polarization of light.
3. The varifocal liquid lens of claim 1 , wherein the first and second fluids are separated by a second interface therebetween, wherein the second interface is coaxial with the first interface and has a variable curvature across the clear aperture.
4. The varifocal liquid lens of claim 3 , wherein the second fluid surrounds the first fluid, wherein the second fluid is birefringent, and the first fluid is isotropic.
5. The varifocal liquid lens of claim 1 , wherein the second fluid comprises a polymer-stabilized liquid crystal (LC).
6. The varifocal liquid lens of claim 1 , wherein the second fluid comprises a liquid crystal (LC) elastomer.
7. The varifocal liquid lens of claim 1 , wherein the first interface comprises an elastic membrane.
8. The varifocal liquid lens of claim 7 , wherein the elastic membrane comprises an electrically responsive polymer layer for changing a radius of curvature of the elastic membrane by applying an electric field to the electrically responsive polymer layer.
9. The varifocal liquid lens of claim 7 , wherein the elastic membrane is configured to change its radius of curvature by application of mechanical force to a perimeter of the elastic membrane.
10. The varifocal liquid lens of claim 1 , wherein the first and second fluids are immiscible, and wherein the first interface comprises a boundary between the immiscible first and second fluids.