  Displacement detection of a sphere particle in focused laser beams with
quadrant photodetector (QPD) provides a fast and high precision way to
determine the particle location. In contrast to the traditional Gaussian beams,
the sensitivity of displacement detection using various doughnut beams are
investigated. The sensitivity improvement for large sphere particles along the
longitudinal direction is reported. With appropriate vortex charge $l$ of the
doughnut beams, they can outperform the Gaussian beam to get more than one
order higher sensitivity and thus have potential applications in various high
precision measurement. By using the levitating doughnut beam itself to detect
the particle displacement, the result will also facilitate the recent proposal
of levitating a particle in doughnut beams to suppress the light absorption.
