is so bright. Progress has been made in creating an optical vortex coronagraph to directly observe planets with too low a contrast ratio to their parent to be observed with other techniques. Optical vortices are used in optical tweezers to manipulate micrometer-sized particles such as cells. Such particles can be rotated in orbits around the axis of the beam using OAM. Micro-motors have also been created using optical vortex tweezers. Optical vortices can significantly improve communication bandwidth. For instance, twisted radio beams could increase radio spectral efficiency by using the large number of vortical states. The amount of phase front ‘twisting’ indicates the orbital angular momentum state number, and beams with different orbital angular momentum are orthogonal. Such orbital angular momentum based multiplexing can potentially increase the system capacity and spectral efficiency of millimetre-wave wireless communication. Similarly, early experimental results for orbital angular momentum multiplexing in the optical domain have shown results over short distances, but longer distance demonstrations are still forthcoming. The main challenge that these demonstrations have faced is that conventional optical fibers change the spin angular momentum of vortices as they propagate, and may change the orbital angular momentum when bent or stressed. So far stable propagation of up to 50 meters has been demonstrated in specialty optical fibers. Free-space transmission of orbital angular momentum modes of light over a distance of 143 km has been demonstrated to be able to support encoding of information with good robustness. Current computers use electronics that have two states, zero and one. Quantum computing could use light to encode and store information. Optical vortices theoretically have an infinite number of states in free space, as there is no limit to the topological charge. This could allow for faster data manipulation. The cryptography community is also interested in optical vortices for the promise of higher bandwidth communication discussed above. In optical microscopy, optical vortices may be used to achieve spatial resolution beyond normal diffraction limits using a technique called Stimulated Emission Depletion (STED) Microscopy. This technique takes advantage of the low intensity at the singularity in the center of the beam to deplete the fluorophores around a desired area with a high-intensity optical vortex beam without depleting fluorophores in the desired target area. Optical vortices can be also directly (resonantly) transferred into polariton fluids of light and matter to study the dynamics of quantum vortices upon linear or nonlinear interaction regimes.