Large Kerr nonlinearity in PdSe2 2D films

Abstract

<p>We report a large third-order nonlinear optical response of palladium diselenide (PdSe<sub>2</sub>) films – a two-dimensional (2D) noble metal dichalcogenide material. Both open-aperture (OA) and closed-aperture (CA) Z-scan measurements are performed with a femtosecond pulsed laser at 800 nm to investigate the nonlinear absorption and nonlinear refraction, respectively. In the OA experiment, we observe optical limiting behaviour originating from large two photo absorption (TPA) in the PdSe<sub>2</sub> film of <i>β =</i> 3.26 × 10<sup>-8</sup> m/W. In the CA experiment, we measure a peak-valley response corresponding to a large and negative Kerr nonlinearity of <i>n</i><sub>2</sub> = -1.33×10<sup>-15</sup> m<sup>2</sup>/W – two orders of magnitude larger than bulk silicon. We also characterize the variation of <i>n</i><sub>2</sub> as a function of laser intensity, observing that <i>n</i><sub>2</sub> decreases in magnitude with incident laser intensity, becoming saturated at <i>n</i><sub>2</sub> = -9.96×10<sup>-16</sup> m<sup>2</sup>/W at high intensities. These results verify the large third-order nonlinear optical response of 2D PdSe<sub>2</sub> as well as its strong potential for high performance nonlinear photonic devices.</p>

Enhanced 3 rd order optical nonlinearity in silicon nitride nanowires integrated with 2D graphene oxide films

“…The increasing demand for high performing nonlinear integrated photonic devices has motivated the search for highly nonlinear materials [20,29]. The superior Kerr nonlinearity of 2D layered materials such as graphene, graphene oxide (GO), black phosphorus and transition metal dichalcogenides (TMDCs) has been widely recognized and has enabled diverse nonlinear photonic devices with high performance and new functionalities [29][30][31][32][33][34][35][36][37][38][39][40]. In particular, tunable FWM in graphene-covered SiN waveguides has been demonstrated by electronically tuning the Fermi energy of graphene [31].…”