Significant impact of light-matter strong coupling on chiral nonlinear optical effect

Light-matter strong coupling (LMSC) is intriguing state in which light and matter are coherently hybridized inside cavity. It has been gaining widespread recognition as an excellent way for controlling material properties without any chemical modification. Here we show the LMSC is a powerful state to manipulate and improve a chiral nonlinear optical (NLO) effect through the investigation of second harmonic generation circular dichroism. At the upper polaritonic band in LMSC, in addition to an enhancement of SHG intensity by more than one order of magnitude, the responsivity to the handedness of circular polarized light is largely modified, where sign inversion and increase of dissymmetric factor is achieved. Quarter wave plate rotation analysis reveals that the LMSC clearly influence the coefficients associated with chirality in NLO process and it also contributes to the enhancement of nonlinear magnetic dipole interactions. This study demonstrates that LMSC serves as a novel platform for control of chiral optoelectronics and magneto-optics.