Fig. 3: Disentangling THG and SFG signals by polarized detection.
From: All-optical polarization encoding and modulation by nonlinear interferometry at the nanoscale

a Delay traces of the (0, +1) diffraction order at 3ω, analyzed with a linear polarizer selecting the light linearly polarized along the x (green) or y (blue) axis in the detection path. When the linear polarizer is aligned along x, the trace shows a delay-independent behavior, ascribed to the THG component (green). In contrast, when the linear polarizer is aligned along y, the trace exhibits a bell-shaped profile with null offset (blue), characteristic of the SFG component. THG and SFG powers at the zero-delay condition have been equalized by adjusting the pump powers, to enable polarization modulation between orthogonal circular polarization states. b Same as (a) for the (0, –1) diffraction order