Noncollinear excitation of surface plasmons for triangular structure formation on Cr surfaces by femtosecond lasers

Abstract Utilizing double time-delayed femtosecond laser pulses with different linear polarizations, we achieve the regular subwavelength triangular structure arrays on chromium surfaces in one-step processing. Both measurement and characterization reveal that such surface structures are constituted by interlocking of three ablation gratings oriented along different directions. The comprehensive investigation of the structure formation is performed by varying laser parameters such as the energy ratio, the temporal delay and the polarization discrepancy between double pulses. It is found that the ratio of double laser energies is critical for the uniform triangular structure formation especially within a temporal delay range of -10 ps