Interaction mechanism between femtosecond laser and diamond

Abstract Recently, the femtosecond laser with ultra-short pulse and high instantaneous energy become a flexible tool for processing diamond which is widely applied in industry due to the excellent properties of the diamond such as high hardness and wide optical bandgap. However, the mechanisms of the interaction between femtosecond laser and diamond was still unclear. Thus, in this work we integrated techniques such as a self-developed femtosecond pump–probe temporal evolution imaging detection, a femtosecond transient absorption spectroscopy and a confocal Raman microscope to investigate the mechanisms of the interaction between femtosecond laser and diamond such as nonlinear absorption of the laser energy, the energy transfer and transition and materials removal mechanism. The results indicated that the nonlinear absorption of laser energy of the diamond was mainly occurred within about 50 ps by the interaction between photons and electrons in the femtosecond laser processing. The energy transfer and transition was lasted for about 3 ns by the transmission chain of photons-electrons-lattice-continuous medium in the diamond during the femtosecond laser processing. The mechanism of the material removal in the femtosecond laser of diamond was the combined effect of the phase transformation, the stress effect and the plasma impact wave. The results also showed that when the pulse laser energy was 3.8 μ J, the diamond was ablated without obvious graphitization phase transformation. However, when the pulse energy increased up to 26.58 μ J, the graphitization transformation was a factor of the materials removal as a G peak near the wavelength of 1580 cm −1 was detected.