Bulk photovoltaic effects in the presence of a static electric field

Irradiated crystalline insulators in the presence of a static electric field exhibit three new types of nonlinear photocurrents. They represent physical singularities of the third order free electron polarization susceptibility and hence generalize the standard second order bulk photovoltaic effects. In the absence of momentum relaxation and saturation effects they grow as tⁿ (n=2,1,0) with illumination time and are dubbed jerk, modified injection, and modified shift current, respectively. The presence of a static electric field gives rise to new processes which are described in detail. Experimental signatures and extensions to higher order susceptibilities are also discussed.