Nonlinear optical absorption switching behavior of BaTiO3 in asymmetric microcavity

In this paper, an asymmetric 1-D photonic microcavity with BaTiO3 as defect has been fabricated using RF magnetron sputtering technique. Open aperture Z-scan shows enhancement in nonlinear absorption of BaTiO3 due to strong field confinement around the defect layer. We further report the switching behavior in nonlinear absorption from reverse saturable absorption to saturable absorption in response to the angle tuning of the sample. The transfer matrix simulation results further support the cavity defect in asymmetric photonic crystal confine the photon and thereby enhancing nonlinear optical phenomena. •Optical field confinement in BaTiO3 embedded asymmetric microcavity.•Strong enhancement in nonlinear optical absorption for microcavity relative to the pure BaTiO3 film.•Switchable reverse saturable absorption to saturable absorption is demonstrated.•Potential saturable absorber for laser devices.