Laser-induced ablation of tantalum in a wide range of pulse durations

Abstract

We present data and analysis of the laser-induced ablation of pure tantalum (Ta, $$Z=73$$ Z = 73 ). We have identified different physical regimes using a wide range of laser pulse durations. A comparison of the influence of strongly varying laser pulse parameters on high-Z materials is presented. The crater depth caused by three different laser systems of pulse duration $${\varDelta }\tau _1=5\,\mathrm {ns}$$ Δ τ 1 = 5 ns and wavelength $$\lambda _1=1064\,\mathrm {nm}$$ λ 1 = 1064 nm , $${\varDelta }\tau _2=35\,\mathrm {ps}$$ Δ τ 2 = 35 ps , $$\lambda _2=355\,\mathrm {nm}$$ λ 2 = 355 nm and $${\varDelta }\tau _3=8.5\,\mathrm {fs}$$ Δ τ 3 = 8.5 fs , $$\lambda _3=790\,\mathrm {nm}$$ λ 3 = 790 nm are analyzed via confocal microscopy as a function of laser fluence and intensity. The minimum laser fluence needed for ablation, called threshold fluence, decreases with shorter pulse duration from $$1.10\,\mathrm {J/cm}^2$$ 1.10 J / cm 2 for the nanosecond laser to $$0.17\,\mathrm {J/cm}^2$$ 0.17 J / cm 2 for the femtosecond laser.

A concept for the extraction of the most refractory elements at CERN-ISOLDE as carbonyl complex ions

“…An upper limit for the fluence per pulse computes to φ l < 5× 10 −3 J cm −2 4.The minimum laser fluence needed for ablation (threshold fluence) was estimated in Ref. [83] to be 0.17 J cm 2 at λ l = 750 nm and a pulse length of τ p = 8.5 f s. Thus, the source in our experiment was most likely not operated in an ablation regime. The efficiency is given for the most abundent fragment of Mo(CO) 6 , and corrected for isotope abundance.…”

A concept for the extraction of the most refractory elements at CERN-ISOLDE as carbonyl complex ions

“…The minimum laser fluence needed for ablation (threshold fluence) was estimated in ref. [86] to be 0.17 J cm −2 at λ l = 750 nm and a pulse length of τ p = 8.5 fs. Thus, the source in our experiment was most likely not operated in an ablation regime.…”