Intense femtosecond photoexcitation of bulk and monolayer MoS2

The effect of femtosecond laser irradiation on bulk and single-layer MoS2 on silicon oxide is studied. Optical, field emission scanning electron microscopy and Raman microscopy were used to quantify the damage. The intensity of A1g and E2g1 vibrational modes was recorded as a function of the number of irradiation pulses. The observed behavior was attributed to laser-induced bond breaking and subsequent atoms removal due to electronic excitations. The single-pulse optical damage threshold was determined for the monolayer and bulk under 800 nm and 1030 nm pulsed laser irradiation, and the role of two-photon versus one photon absorption effects is discussed.