Laser writing with sub-nanosecond burst of femtosecond pulses using strain accumulation

Femtosecond laser direct writing and micromachining attract considerable interest for a variety of applications ranging from integrated optics and microfluidics to printable flat optics and multi-dimensional optical data storage. A regular train of femtosecond pulses generated by femtosecond oscillator or regenerative amplifier does commonly used in laser material processing. Micromachining with sub-microsecond bursts of femtosecond pulses has been applied for morphology control of structures generated via accumulation and regulation of a heat deposition [1,2]. In addition to heating a pressure wave and rarefaction in the modified zone are important factors determining the laser induced structural changes [3]. However there is a lack of laser processing experiments with a burst exploiting accumulation of the rarefaction