Optical lift from dielectric semicylinders

A wave optics numerical analysis of the force and torque on a semicylindrical optical wing is presented. Comparisons with a recently reported ray optics analysis indicate good agreement when the radius is large compared with the wavelength of light, as expected. Surprisingly, we find that the dominant rotationally stable angle of attack at α ≈ -15° is relatively invariant to changes in radius and refractive index. However, the torsional stiffness at the equilibrium point is found to increase, approximately, as the cubic power of the radius. Quasi-resonant internal modes of light produce complex size-dependent variations of the angle and magnitude of the optical lift force.