Fabry–Pérot microcavity-integrated solid-state laser for wavelength-selective passive Q-switching

Wavelength tailoring in solid-state lasers faces significant challenges arising from gain bandwidth limitations, thermal management constraints, and the inherent trade-off between intracavity wavelength control and system compactness. We demonstrate a new paradigm for wavelength-selective, passively Q-switched bulk lasers implemented with Fabry-Pérot microcavity-structured (FPM) crystals. Rate equations describing passive Q-switching laser behavior with FPM crystals are derived. By synergistically integrating the gain bandwidth broadening and wavelength-selective functions of FPM crystals with the GaAs-microwire (MW)-network saturable absorbers, we achieved equidistant six-wavelength passively Q-switched lasing using an FPM crystal comprising Yb:SYB and Yb:CNGS media. The characteristics of the emission wavelengths were interpreted using F-P filter theory. We also investigated the thermal transport properties of the GaAs-MW network, thereby providing design guidelines for thermal management in devices with disordered network architectures. This Q-switching laser design strategy can be extended to gain media spanning various emission bands. These results offer a new pathway for developing all-solid-state, wavelength-customized pulsed light sources.