INVESTIGATIONS ON MICROSTRUCTURING OF FERROELECTRIC MATERIALS BY PICOSECOND UV LASER PULSES

摘要

Characteristics of laser micromachining of lithium niobate (LiNbO_3) and lithium tantalate (LiTaO_3) using 10 ps laser pulses at 355 nm wavelength were investigated. The ablation thresholds were determined in dependence on pulse repetition rates and feed rates in comparison with single shot experiments. The single shot ablation threshold for LiNbO_3 was determined to 1.7 J/cm~2 and for LiTaO_3 to 3.1 J/cm~2. Ablation rates as well as surface roughness of the laser ablated materials at different pulse energies were measured. An arithmetical mean deviation of the roughness profile of 130 nm was achieved. Based on these results the potential of laser micromachining of ferroelectric materials with ps laser pulses have been demonstrated by a laser machined ridge waveguide structure.