Generation of a Collimated Doughnut-Beam for Atom Trapping Using a Single-Cone Axicon

We propose a novel method to generate a collimated doughnut-beam (DB) using only one single-cone axicon and realize it experimentally. The diameter of the DB is estimated by ray optics and is in good agreement with the experimental results. The CCD image of the DB and the radial light intensity distribution are experimentally obtained. The light intensity of the DB dark inner region is about 1% of the peak intensity of the DB. The far-field divergent angle is about 6 mrad and seems to be well-collimated. With optimum values of the power and the positive detuning of the laser field, the optical dipole potential of the DB can be chosen to be very large as a good confinement for atom trapping.