Generation of higher-order Bessel beams by spiral slits using digital micromirror device
We generate higher-order Bessel beams (HOBBs) from spiral slits programmed in a digital micromirror device (DMD). Using particular spiral slit widths and extents results in the presence of a central dark core on the intensity profile of the generated vortex beams, a prominent feature of HOBBs. Such a feature arises because the spiral shape of the slit induces an azimuthal phase change on the incoming plane wave. By modulating the shape of the spiral slits, HOBBs of different orbital angular momentum (OAM) content are produced. We believe that our study provides a fast and direct method to generate OAM-carrying vortex beams convenient for various applications such as optical tweezing, laser physics, and optical communication.