Fig. 5.

Normalized lateral irradiance profiles at the focus (z = 0) of a Gaussian beam (diffraction-based simulations) when a single silica bead with a 10-µm radius was placed at various locations (x_bead = 0, 2, 4… 50 µm; z_bead = 10, 200 µm) near the focus of the beam. Significant beam steering and distortion of the Gaussian beam focus was observed when the bead was positioned near the focus (z_bead = 10 µm); however, negligible beam steering and distortion were observed when the bead was positioned further from the focus (z_bead = 200 µm). The scale bar measures 1 µm.