MgSiP2: An Infrared Nonlinear Optical Crystal with a Large Non-Resonant Phase-Matchable Second Harmonic Coefficient and High Laser Damage Threshold

Jingyang He, Yingdong Guan, Victor Trinquet, Guillaume Brunin, Ke Wang, Robert Robinson, Rui Zu, Suguru Yoshida, Seng Huat Lee, Yu Wang, Yanglin Zhu, Gian Marco Rignanese, Zhiqiang Mao, Venkatraman Gopalan

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Superior infrared nonlinear optical (NLO) crystals are in urgent demand in the development of lasers and optical technologies for communications and computing. The critical challenge is to find a crystal with large non-resonant phase-matchable NLO coefficients and high laser damage threshold (LDTs) simultaneously, which however scale inversely. This work reports such a material, MgSiP2, that exhibits a large second harmonic generation (SHG) coefficient of d14≈d36 = 89 ± 5 pm V−1 at 1550 nm fundamental wavelength, surpassing the commercial NLO crystals AgGaS2, AgGaSe2, and ZnGeP2. First principles theory reveals the polarizability and geometric arrangement of the [SiP4] tetrahedral units as the origin of this large nonlinear response. Remarkably, it also exhibits a high LDT value of 684 GW cm−2, which is six times larger than ZnGeP2 and three times larger than CdSiP2. It has a wide transparency window of 0.53–10.35 µm, allowing broadband tunability. Further, it is Type I and Type II phase-matchable with large effective SHG coefficients of deff,I ≈80.2 pm V−1 and deff,II ≈73.4 pm V−1. The outstanding properties of MgSiP2 make it a highly attractive candidate for optical frequency conversion in the infrared.

Original languageEnglish (US)
Article number2301060
JournalAdvanced Optical Materials
Issue number24
StatePublished - Dec 18 2023

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics

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