Ultrafast Nonlinear Absorption and Second Harmonic Generation in Cu<sub>0.33</sub>In<sub>1.30</sub>P<sub>2</sub>S<sub>6</sub> van der Waals Layered Crystals
Aamir Mushtaq, Liam Clink, Mohamed Yaseen Noor, Conrad Kuz, Emma DeAngelis, Ryan Siebenaller, Adam Fisher, Darpan Verma, Roberto C. Myers, Benjamin S. Conner, Michael A. Susner, Enam Chowdhury
Abstract
The advancement of ultrafast photonics and optoelectronic devices necessitates the exploration of new materials with optical and chemical stability to implement practical applications. Layered quaternary metal-thio/selenophosphate has attracted much interest over the past few years. Ferroelectric CuInP2S6 (CIPS) is an emerging material that belongs to this family. When synthesized with Cu deficiencies, CIPS forms self-assembled in-plane heterostructures, which in turn exhibit properties that are both compositionally and thermally dependent. These characteristics can be explored for applications in nonlinear optoelectronic and photonic devices. Herein, we study the second and third order nonlinear optical behavior of Cu0.33In1.30P2S6 bulk heterostructure. We observed large two photon induced nonlinear absorptions and self-defocusing at 1032 nm pulsed laser excitation using the Z-scan technique. Furthermore, we identified a polarization-dependent second harmonic signal and determined the laser-induced optical damage threshold. Our observations allow for the designing of optoelectronic and ultrafast photonic devices based on these materials.