ASLD's rate equation systems facilitate the simulation of resonator modes, including co-doped materials and various interionic mechanisms like upconversion and energy transfer. Users can customize rate equations through an intuitive GUI, accurately modeling resonator dynamics and thermal lens effects in laser crystals. ASLD accommodates gain mediums like Nd:YAG, Ho:YAG, Er:YAG, Er:glass, and Tm, Ho:YAG, considering multiple levels, temperature-dependent emission cross-section, and reabsorption.