Spherical aberration correction for optical tweezers

Abstract

In typical optical tweezers experiments the quality of the trap deteriorates due to optical aberrations caused by the refractive index mismatch at the glass–water interface when trapping deep inside a sample or out of the imaging plane. We investigate this effect experimentally by monitoring the two-photon fluorescence of trapped dye-stained polystyrene spheres. We also partly corrected the aberrations by optimising the fluorescence signal using an adaptive deformable membrane mirror.