The University of Central Florida houses a wide array of ultrafast laser systems operating in the regimes of long wavelength and high-average power, most of which fall under the umbrella of iFAST (Institute for the Frontier of Attosecond Science and Technology). The lasers are coupled to ultrahigh vacuum setups for generating and characterizing attosecond XUV and soft x-ray pulses and other secondary sources. The team also has expertise in the simulation of attosecond photoionization processes. Recent accomplishments of the team include the generation of 53 attosecond soft x-ray pulses, 50-fold compression of ytterbium-doped laser amplifiers to below two optical cycles, and attosecond transient absorption spectroscopy in the soft x-ray “water window”.
The iFAST OPCPA is a Ti:Sapphire-pumped optical parametric chirped pulse amplifier producing <10 fs, 3 mJ pulses at a central wavelength of 1.8 µm and 1 kHz repetition rate. The carrier-envelope phase of the laser is passively stable, with RMS phase error below 100 mrad over a measurement period of one hour. The iFAST FOPA (currently in development) will increase the pulse energy to 100 mJ, while maintaining few-cycle pulse duration in the short-wave infrared. The iFAST CPA is a Cr:ZnSe chirped pulse amplifier seeded by an optical parametric amplifier, which generates 44 fs, 4 mJ, 1 kHz pulses at a center wavelength of 2.5 µm.The contact person for the iFAST lasers is Prof. Zenghu Chang (Zenghu.Chang@ucf.edu).
Other lasers available on-site include Yb:solid-state and Yb:fiber amplifiers, offering sub-millijoule pulse energies at repetition rates up to 200 kHz and pulse durations as short as 1.5 optical cycles, and OPA sources operating in the mid- to long-wave infrared. A high-average power petawatt-class laser operating at 2 micron wavelength is currently in the planning stages. The contact persons for these laser sources are Dr. Mike Chini (Michael.Chini@ucf.edu) and Dr. Li Fang (Li.Fang@ucf.edu).
|Center Wavelength||1.8 µm||1.8 µm||2.5 µm||1.03 µm||1.03 µm|
|Pulse duration (FWHM)||10 fs||10 fs||44 fs||<6 fs||<10 fs|
|Pulse energy||3 mJ||100 mJ||4 mJ||>0.2 mJ||>0.2 mJ|
|Repetition Rate||1 kHz||10 Hz||1 kHz||50 kHz||200 kHz|
|Carrier-Envelope Phase Stability||<100 mrad||<200 mrad||TBD||<300 mrad||N/A|
The facilities include beamlines for attosecond soft x-ray and femtosecond infrared pulses, including attosecond streaking spectroscopy and attosecond transient absorption spectroscopy, and for high-intensity attosecond pump-attosecond probe experiments in the extreme ultraviolet. Experimental setups for attosecond interferometry, photoelectron/photoion spectroscopy, and solid-state high-order harmonic generation are also available.
The group of Luca Argenti develops and applies state-of-the-art ab initio and model software to the ionization of atoms and molecules under the action of arbitrary and moderately intense sequences of ultrashort pulses of ionizing radiation, with an emphasis on the accurate description of electronic correlation in the ionization continuum in general and on the dynamics of metastable states in particular. Dr. Argenti's research has supported the experimental effort of several laboratories in the US, Japan, and Europe that employ attosecond photoelectron and transient absorption spectroscopies.