Phase Matching, Strong Frequency Doubling, and Outstanding Laser-Induced Damage Threshold in the Biaxial, Quaternary Diamond-like Semiconductor Li4CdSn2S7

摘要

The novel diamond-like Li_(4)CdSn_(2)S_(7) possesses many outstanding attributes that enable it to be a new, well-rounded front-runner among infrared (IR) nonlinear-optical materials, especially for high-intensity laser applications. Distortions of the metal–sulfur tetrahedra in accordance with Pauling’s second rule give rise to a significant net dipole moment, resulting in a strong second-order nonlinear optical susceptibility (χ~((2))) of 35.0 ± 3.5 pm/V. Li_(4)CdSn_(2)S_(7) possesses an optical bandgap of 2.59 eV and an exceptional laser-induced damage threshold of >2.5 GW/cm~(2), which is more than 12.5 times greater than that of AgGaSe_(2) measured under identical irradiation conditions. Li_(4)CdSn_(2)S_(7) possesses a melting point of ∼780 °C and phase-matchability. All data indicate that Li_(4)CdSn_(2)S_(7) will outperform AgGaS_(2) and AgGaSe_(2) in difference frequency generation schemes for the generation of mid-IR radiation. New information on the recently reported Li_(2)CdSiS_(4), which Li_(4)CdSn_(2)S_(7) also outperforms, is additionally included.