• • AlGaS3 exhibits a wide experimental band gap of ~3.38 eV, which is 0.68 eV larger than that of AgGaS2 (2.70 eV), directly contributing to a high laser-induced damage threshold (LIDT) of ~6.0× AGS, making it suitable for high-power IR laser applications.
• • The material shows a phase-matching SHG response of ~0.5× AGS at 2.09 μm, with particle size-dependent SHG intensities confirming phase-matchability, essential for efficient frequency conversion in practical devices.
• • The crystal structure comprises [AlS4] and [GaS4] tetrahedra, where the wide HOMO-LUMO gap of [AlS4] enhances band gap and LIDT, while [GaS4] provides NLO activity, demonstrating a successful design strategy.
• • AlGaS3's LIDT (~6.0× AGS) is among the highest reported for IR NLO materials with Eg ≥ 2.80 eV and SHG ≥ 0.5× AGS, indicating a superior trade-off between damage resistance and nonlinearity.