Two-photon absorption and non-resonant electronic nonlinearities of layered semiconductor TIGaS2

The ultrafast nonlinear optical properties of bulk TIGaS2 crystal, a semiconductor with a layered structure, are studied by combining intensity dependent transmission, time-resolved transient absorption, and optical Kerr effect coupled to optical heterodyne detection. TIGaS2 demonstrates obvious two-photon absorption and electronic nonlinearities at 800 nm. The two-photon absorption coefficient and the nonlinear refractive index are determined to be of the order of 10(-10) cm/W and 10(-14) cm(2)/W, respectively. Furthermore, both the real and imaginary parts of the complex third-order susceptibility tensor elements are extracted. The large ultrafast optical nonlinearities make TIGaS2 a promising material for application in photonic techniques. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement