Anisotropic Ta₂PdSe₆ modulator for polarization-controllable pulsed lasers in the mid-infrared band

Mid-infrared all-solid-state pulsed lasers are of great significance in industrial processing, military defense, and biomedical fields. However, achieving pulsed lasers with controllable output parameters in the mid-infrared range remains challenging due to the limited availability of efficient optical modulators. Anisotropic materials, owing to their polarization-dependent optical responses, offer promising opportunities for polarization-controllable mid-infrared lasers. Here, we report what we believe to be a novel optical modulator based on the anisotropic material Ta₂PdSe₆, enabling polarization-controllable Q-switched and Q-switched mode-locked operations at 2 µm. In the Q-switched state, pulse widths of 561.6 ns and 733.4 ns were obtained for horizontal and vertical polarizations, respectively. In the Q-switched mode-locked state, pulse durations of 2.39 ns and 2.42 ns were recorded under the corresponding polarization directions. This study demonstrates the unique advantages of anisotropic materials in the development of polarization-dependent photonic devices and provides a new perspective for designing solid-state lasers with controllable output parameters.