Centrifugal photovoltaic and photogalvanic effects driven by structured light

TL;DR

This paper demonstrates that structured light with orbital angular momentum can induce steady charge separation and photocurrents in semiconductor rings, offering a new way to enhance photovoltaic effects through light structuring.

Contribution

It introduces a novel method of generating photovoltaic effects by structuring light to transfer orbital angular momentum to semiconductor rings, controlling charge buildup and photocurrents.

Findings

Charge accumulation at ring boundaries can generate open circuit voltage.

Orbital angular momentum of light enhances the centrifugal potential.

Charge buildup and photocurrent are controllable via light pulse parameters.

Abstract

Much efforts are devoted to material structuring in a quest to enhance the photovoltaic effect. We show that structuring light in a way it transfers orbital angular momentum to semiconductor-based rings results in a steady charge accumulation at the outer boundaries that be utilized for the generation of an open circuit voltage or a photogalvanic (bulk photovoltaic) type current. This effect which stems both from structuring light and matter (confinement potentials), can be magnified even at fixed moderate intensities, by increasing the orbital angular momentum of light which strengthens the effective centrifugal potential that repels the charge outwards. Based on a full numerical time propagation of the carriers wave functions in the presence of light pulses we demonstrate how the charge buildup leads to a useable voltage or directed photocurrent whose amplitudes and directions are controllable by the light pulse parameters.