Abstract-Discrimination of orbital angular momentum modes of the terahertz vortex beam using a diffractive mode transformer

Discrimination of orbital angular momentum modes of the terahertz vortex beam using a diffractive mode transformer

Changming Liu, Xuli Wei, Liting Niu, Kejia Wang, Zhengang Yang, and Jinsong Liu

We present an efficient method to discriminate orbital angular momentum (OAM) of the terahertz (THz) vortex beam using a diffractive mode transformer. The mode transformer performs a log-polar coordinate transformation of the input THz vortex beam, which consists of two 3D-printed diffractive elements. A following lens separates each transformed OAM mode to a different lateral position in its focal plane. This method enables a simultaneous measurement over multiple OAM modes of the THz vortex beam. We experimentally demonstrate the measurement of seven individual OAM modes and two multiplexed OAM modes, which is in good agreement with simulations.

© 2016 Optical Society of America

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