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Improved backscattering detection in photonic force microscopy near dielectric surfaces with cylindrical vector beams

Abstract:

Cylindrical vector beams are used to improve back scattering detection in photonic force microscopy measurements near a dielectric surface. We compare back focal plane interferometry signals acquired on a quadrant photodiode when optical trapping a latex microparticle with gaussian, radial, and azimuthal beams. We find a consistent reduction of the interference pattern generated by the superposition of light backscattered by the trapped particle and backreflected by the dielectric surface. We contrast experimental findings with a model based on light scattering theory in the T - matrix formalism.