Raman Photogalvanic Effect: photocurrent at inelastic light scattering

TL;DR

This paper theoretically demonstrates that Raman scattering of light in non-centrosymmetric media can generate a steady dc photocurrent, expanding understanding of light-matter interactions and photogalvanic effects.

Contribution

It introduces the concept of the Raman Photogalvanic Effect (RPGE), providing a microscopic theory for photocurrent generation via inelastic light scattering in specific structures.

Findings

Photocurrent can be induced by Raman scattering in non-centrosymmetric media.

The theory applies to bulk gyrotropic semiconductors and quantum well structures.

RPGE relates to and extends traditional photogalvanic effects.

Abstract

We show theoretically that electromagnetic waves propagating in the transparency region of a non-centrosymmetric medium can induce a dc electric current. The origin of the effect is the Raman scattering of light by free carriers in the system. Due to the photon scattering, electrons undergo real quantum transitions resulting in the formation of their anisotropic momentum distribution and in shifts of electronic wavepackets giving rise to a steady state photocurrent. We present microscopic theory of the Raman Photogalvanic effect (RPGE) focusing on two specific situations: (i) generic case of a bulk gyrotropic semiconductor and (ii) a quantum well structure where the light is scattered by intersubband excitations. We uncover the relation of the predicted RPGE and the traditional photogalvanic effect at the light absorption.