Anti-Resonant Interferometric Nonlinear Spectroscopy (ARINS) study of metal nanocluster-glass composites

Linear and nonlinear optical properties of copper and gold nanoclusters in fused silica glasses synthesized by 200 KeV Cu⁺ and 1.5 MeV Au⁺ ion implantation at a dose of 3x10¹⁶ ions/cm² have been studied. UV-Vis spectroscopy has revealed prominent linear absorption bands at characteristic surface plasmon resonance (SPR) frequency signifying appreciable formation of copper and gold colloids in glass matrices. Third-order optical properties of the nanocluster-glass composite materials have been studied by Z-Scan and Anti Resonant Interferometric Nonlinear Spectroscopy (ARINS) techniques. The sign of the nonlinear refraction is readily obtained from Z-scan signature. The ARINS technique utilizes the dressing of two unequal-intensity counter-propagating pulsed beams with differential nonlinear phases, which occur upon traversing the sample. This difference in phase manifests itself in the intensity-dependent transmission. The nonlinear refractive index, nonlinear absorption coefficient and the real (and imaginary) parts of the third-order optical susceptibility have been extracted from ARINS data. Results of the investigation of the nonlinear refraction using the above two techniques and the possible mechanisms responsible for the nonlinear optical responses are presented in the current paper.