Third harmonic generation in Dirac semimetal Cd3As2
Kaleem Ullah, Yafei Meng, Yue Sun, Yunkun Yang, Xiangjing Wang, Anran Wang, Xinran Wang, Faxian Xiu, Yi Shi, Fengqiu Wang
Abstract
Cadmium arsenide (Cd3As2), an emerging three-dimensional Dirac semimetal, has recently generated significant interest in the area of ultrafast optics and optoelectronics. However, its nonlinear susceptibility has not been experimentally studied; thus, it is not yet possible to evaluate its potential in nonlinear optics. In this work, we investigate third harmonic generation (THG) in a 100 nm thick Cd3As2 film using broadband infrared femtosecond lasers (across 1500–2350 nm). The χ3 of Cd3As2 (2.30 × 10−19 m2 V−2) is obtained by comparing the THG spectra with a glass substrate, graphene, and monolayer MoS2. We further demonstrate a simple approach to enhance the THG signal by introducing an underlying planar micro-cavity. An enhancement of about 420 times in the THG signal was recorded at ≃1560 nm. Our results indicate that Cd3As2 thin films can provide a similar platform for nonlinear optics with respect to graphene and may offer unique potential in the mid-infrared due to its broadband light–matter interaction and excellent tunability.