Nonlinear optical properties of ZrGeTe ₄ at 1.5 μm for the passively Q-switched fiber laser

In this study, the nonlinear optical properties of ZrGeTe4 at 1.5 μm wavelength and its application in passively Q-switched fiber lasers are systematically investigated for the first time. The recovery time of ZrGeTe4 is measured by using the pump-probe technique, which is crucial for evaluating its performance in fast optical switching. For the characterization, SEM, EDS, AFM, TEM were employed to confirm the particle size of the prepared ZrGeTe4 nanoparticles, and the nonlinear optical properties of ZrGeTe4 SA were further investigated by measuring their modulation depth and saturation intensity. The experimental results show that the Q-switched laser based on ZrGeTe4 SA achieves a wide modulation frequency range from 14.95 kHz to 69.39 kHz, and the pulse width can be tuned from 7.22 μs to 1.24 μs. Meanwhile, the output power of the laser varies from 0.25 mW to 3.88 mW, and the single-pulse energy ranges from 16.72 nJ to 57.36 nJ, demonstrating excellent Q-switched performance. This study not only reveals the excellent nonlinear optical properties of ZrGeTe4 at 1.5 μm but also provides a new high-performance SA for passively Q-switched fiber lasers, which plays an important role in promoting the development of laser technology, especially in the fields of compact, high-efficiency laser devices.