  We report, in theory and experiment, on a novel class of controlled light
capsules with nearly perfect darkness, directly employing intrinsic properties
of modified Bessel-Gauss beams. These beams are able to naturally create
three-dimensional bottle-shaped region during propagation as long as the
parameters are properly chosen. Remarkably, the optical bottle can be
controlled to demonstrate various geometries through tuning the beam
parameters, thereby leading to an adjustable light capsule. We provide a
detailed insight into the theoretical origin and characteristics of the light
capsule derived from modified Bessel-Gauss beams. Moreover, a binary digital
micromirror device (DMD) based scheme is first employed to shape the bottle
beams by precise amplitude and phase manipulation. Further, we demonstrate
their ability for optical trapping of core-shell magnetic microparticles, which
play a particular role in biomedical research, with holographic optical
tweezers. Therefore, our observations provide a new route for generating and
controlling bottle beams and will widen the potentials for micromanipulation of
absorbing particles, aerosols or even individual atoms.
