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.

doi:10.1016/j.optcom.2004.03.009