Aberration control in holographic tweezers using image processing

Holographic tweezers are based on computer-generated holograms displayed on a spatial light modulator (e.g. an LCD, DMD etc.). In biological imaging there are many sources of aberrations a spatial light modulator offers the possibility to control these aberrations. In our setup the spatial light modulator is used to modulate the trapping laser as well as to influence the imaging path. The aberrated particle image can be improved by writing a compensation function into the light modulator. The appropriate function is found by iteratively changing a linear combination of Zernike polynomials