Raman spectra before and after laser irradiations of the Ferich olivine. Image (a) Fa₂₉, (b) Fa₅₀, (c) Fa₇₁, and (d) Fa₁₀₀. Spectra in black are the Raman spectra of initial olivine before laser irradiation. The spectra in red and blue represent irradiation conditions of P75mJ and M150mJ, respectively. The initial olivine samples showed typical double peaks between 800 and 900 cm⁻¹, and the positions of the double peaks shifted toward lower wavenumbers with increasing Fa# values. From Fa₂₉ to Fa₁₀₀, the wavenumbers of doublet peak #1 (DB1) decreased from 821 to 815 cm⁻¹, and those of doublet peak #2 (DB2) decreased from 851 to 833 cm⁻¹. The intensity of DB2 gradually decreased and appeared as a shoulder beside the DB1 peak with increasing Fa# value in initial olivine. After laser irradiation, the wavenumber, shape, and FWHM of the doublet peaks did not change substantially. The spectral intensities were greatly reduced by laser irradiation, and the extent of reduction showed no difference under different energy conditions.