Nonlinear optical properties of CsPbI3: synthesis, characterization, and application in passively Q-switched lasers

Halide perovskites, particularly cesium lead iodide (CsPbI3), have garnered significant attention due to their remarkable properties, including strong absorbance across the visible to near-infrared spectrum and a unique electronic structure that enhances their nonlinear optical (NLO) and optoelectronic applications. In this study, CsPbI3 was synthesized using a hot injection technique and incorporated into a methyl methacrylate (MMA) matrix through polymerization to form CsPbI3/PMMA organic glasses. The NLO properties of these glasses were characterized using the Z-scan technique with a nanosecond pulse laser at an excitation wavelength of 532 nm. Notably, the CsPbI3/PMMA organic glasses exhibited a transition from saturable absorption (SA) to reverse saturable absorption (RSA) upon adjusting the input energy. Furthermore, by integrating a fiber ferrule coating-based CsPbI3 saturable absorber (SA) into the laser cavity, we successfully realized a passively Q-switching (PQS) laser with a minimum pulse duration of 4.7 μs and a signal-to-noise ratio (SNR) of 50 dB at 1.55 μm, respectively. Consequently, the experimental findings indicate that CsPbI3NP-based saturable absorbers (SAs) exhibit performance characteristics that are either comparable to or surpass those of conventional nanoparticle-based SAs. This observation underscores the significant potential of CsPbI3-based SAs for applications in pulsed laser sources, suggesting their viability as advanced materials for enhancing laser performance and stability.