Femtosecond laser micromachining study with multiple wavelengths in CVD diamond

Diamond is well known for its many remarkable mechanical, thermal, electric and optical properties. Among its remarkable characteristics, it also presents interesting nonlinear optical effects, thus being a highly desired material for many photonic devices. Therefore, femtosecond laser micromachining can be used as the processing method of such devices due to its high micron/sub-micron resolution. Thus, in this paper, the incubation effect (damage threshold fluence as a function of the number of applied fs-pulses) is studied at 1030, 515 and 343 nm with 216 fs pulses using the zero damage method. By implementing the exponential defect model, the incubation parameter was determined to be (0.14 +/- 0.03) at 1030 nm, (0.3 +/- 0.1) at 515 nm, and (0.13 +/- 0.04) at 343 nm, which indicates that at 515 nm, fewer fs-pulses are necessary to reach the minimum damage fluence value. In addition, a theoretical model of the electron density formed by a single fs-pulse was used to determine the main light-absorption mechanism at 343 nm. Consequently, this work adds to the knowledge of fs-laser micromachining of CVD diamond from near IR to UV.