High Intensity Femtosecond Laser (HIFL)

The High Intensity Femtosecond Laser (HIFL) is a commercial Chirped-Pulse Amplifier (CPA) system with flexible output in repetition rate (10 Hz or 1 kHz) with energy up to respectively 20 mJ and 2 mJ. The Ti:Sapphire oscillator (OSC: Tsunami - Spectra Physics) is pumped by a Nd:YLF doubled CW laser (PUMP1: Millenia - Spectra Physics) generates sub-35 femtosecond pulses with a spectrum centered at 800 nm. It is capable of generating an 80 MHz pulse train of transform limited pulses, ~5 nJ in energy and <35 fs in duration.

The output is directed through an Acousto-Optic Programmable Dispersive Filter pulse shaper (DAZ: Dazzler - Faslite) which is typically used to correct for pulse narrowing in the last pass of the laser amplifier, but may be used for arbitrary pulse shape and temporal profile generation. This shaped pulse is then expanded in grating stretcher (STR) about 10,000 times its initial pulse duration for safe and efficient amplification in a regenerative amplifier.

This stretched beam is then directed into a regenerative amplifier (REG) pumped by a diode-pumped, kHz repetition rate, Q-switched, intra-cavity doubled, Nd:YLF laser (PUMP3: Evolution 30 - Spectra-Physics), where it is amplified in ~12 passes to an energy of ~3 mJ. This amplified pulse can then be directed into a grating compressor (COMP) for an output of ~2.4 mJ and 30 fs at 1 kHz or may be directed into a 2-pass power amplifier (DP) pump by a 600 mJ Nd:YAG laser (PUMP2: Quanta-Ray Pro 290 - Spectra-Physics) for further amplification to >30 mJ prior to pulse compression. The 10 Hz output is typically 30 mJ and 30 fs. Pulse temporal parameters are measured with a Grenouille from Swamp Optics. Pulse spatial profile is measured using a Spiricon 980 camera and associated hardware/software.