Thermal‐Structural Interfacial Memory Enabled Dual‐Recovery‐Channel Photonic Absorbers for High‐Repetition‐Rate 2 µm Pulse Generation

ABSTRACT The output unpredictability of two‐dimensional‐material‐based passively Q‐switched lasers arises not only from the complexity of absorber parameters, but also from interfacial thermal–structural states modified by continuous strong‐field irradiation, which makes loss recovery dependent on previous irradiation history. Conventional models usually treat saturable absorbers as static loss elements or single‐recovery‐time units, neglecting interfacial memory states accumulated across pulse periods. Here, we propose an interfacial‐memory‐state‐dominated dual‐recovery‐channel model, in which MoS 2 and Ti 3 C 2 T x are described as dynamic nonlinear loss units with fast and slow recovery components. Thermal–structural descriptors from finite‐element and molecular dynamics simulations, including temperature‐field features and RDF parameters, are introduced to represent the interfacial memory state. A physics‐constrained progressive multi‐task learning framework is further developed for inverse design of dual‐passive concentration combinations using only single‐passive experimental data. For the experimental prediction in this work, the developed physical model identifies 0.025 mg/mL MoS 2 and 0.02 mg/mL Ti 3 C 2 T x as the optimal combination and achieves minimum prediction errors of 0.73%, 0.33%, and 0.87% for output power, pulse repetition frequency, and pulse width, respectively. Stable pulses of 58.58 ns at 934.2 kHz are experimentally achieved under 26.11 W pump power. This work provides a prediction‐driven optimization strategy for high‐repetition‐rate pulsed lasers.