Comparison of the thickness of the laser alteration layer formed in different types of olivine and irradiation energies. Four types of olivine, Fa₂₉ (yellow), Fa₅₀ (in purple), and Fa₇₁ (in green), Fa₁₀₀ (in blue), and five total energy levels (P5mJ, P25mJ, P75mJ, M75mJ, and M150mJ) were compared. The bars represented median values of the laser alteration layer thicknesses. The thicknesses of the laser alteration layer of Fa₂₉, Fa₅₀, and Fa₇₁ are not significantly different at the same energy, and the thickness of the laser alteration layer produced by Fa₁₀₀ is significantly thicker than the other groups with increasing energy. At different energies, the thickness of the laser alteration layer was positively correlated with the Fe content.