Observation of Kerr nonlinearity and Kerr-like nonlinearity induced by terahertz generation in LiNbO3

Abstract

Femtosecond laser pulses interacting with LiNbO 3 has been widely applied in intense terahertz generation, excitation and imaging of phonon polaritons and modulating light. It is of great importance to study the nonlinearities induced by femtosecond laser pulses in LiNbO 3 . Here, we demonstrate that both Kerr nonlinearity and Kerr-like nonlinearity induced by terahertz wave occur under the interaction between laser pulses and LiNbO 3 using optical pump-probe techniques. We show that the contribution of Kerr-like nonlinearity to pump-probe spectra varies with the interaction length because of the phase mismatching between terahertz wave and laser pulse. We also observed the excitation of the low frequency phonon polaritons. Experimental results are in consistent with theoretical calculation.

Fano-Resonant Metasurface with 92% Reflectivity Based on Lithium Niobate on Insulator

“…Fortunately, with the rapid development of micro/nano processing technology and the emergence of lithium niobate on insulator (LNOI) [ 4 ], researchers have proposed various processing techniques for thin-film LN, such as thermal diffusion or plasmon exchange [ 5 ], femtosecond laser direct writing [ 6 , 7 ], focused ion beam etching [ 8 ], and plasma dry etching [ 9 ]. Thanks to these advanced processing techniques, a variety of high-performance integrated photonic devices based on LNOI have been proposed, including low-loss waveguides [ 10 ], electro-optical modulators [ 11 , 12 ], micro-resonators [ 13 , 14 ], metamaterials [ 15 ], nonlinear optical devices [ 16 , 17 ], and so on. These research findings have greatly contributed to the prosperity and development of integrated photonics based on LNOI.…”