Helical light bearing orbital angular momentum, so-called “twisted light,” is emerging as a useful substrate for quantum information and communication. However, its interaction with materials presents unique challenges, and transient absorption studies using it are still extremely scarce. Unlike spin, the orbital angular momentum is encoded in a delocalized fashion across the mode of the beam, suggesting that delocalized excitations are required for a material’s internal quantum states to couple to it. If such coupling could successfully be accomplished, however, new types of transient optical signals would appear, owing to the current densities generated by the azimuthal momentum of the light. Using twisted pump/planar probe spectroscopy, we probe the material response of a variety of bulk GaAs semiconductors to twisted light. Upon variation of the orbital angular momentum in the light, we observe transient spectral and dynamical changes in the sample. These differences may form a basis for solid state sensors of photon orbital angular momentum.

Driving delocalized dynamics using the orbital angular momentum of light

253rd National Meeting (2017)

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