摘要
Orbital angular momentum(OAM)of photons offers an additional degree of freedom by accessing the spatial structure of light beams.The most attractive property of OAM is its infinite number of eigen states.These OAM states constitute an infinite dimensional Hilbert space,contributing to a series of high-dimensional scenarios which could not be realized before.Since its first introduction for light beams 30 years ago,1 OAM has benefited many advanced applications ranging from classical to quantum physics.2–6 Much effort has been made for OAM generation.
