Single-cycle, carrier-envelope phase locked lasers at 8 micron
Abstract
Few-cycle Ti:Sapphire lasers centered at 800 nm have been working horses for attosecond pulse generation for the last 17 years. The spectral range of isolated attosecond pulses with sufficient photon flux for time-resolved pump-probe experiments has been limited to extreme ultraviolet (10 to 150 eV). It was demonstrated in 2001 that the cutoff photon energy of high harmonic spectrum can be extended by increasing the center wavelength of driving lasers. In recent years, mJ level, two-cycle, carrier-envelope phase stabilized lasers at 1.6 to 2.1 micron have been developed by compressing pulses from Optical Parametric Amplifiers (OPA) with gas-filled hollow-core fibers or by implementing Optical Parametric Chirped Pulse Amplification (OPCPA) techniques. When a 3 mJ, 12 fs laser centered at 1.7 micron laser was used to implement polarization gating, isolated X-ray pulses with 53-as duration have been characterized by attosecond streaking measurements in Zenghu ChangÕs laboratory. Such ultrabroadband light sources are now being used in time-resolved X-ray absorption near edge structure measurements for studying charge dynamics in atoms, molecules and solids. As new generation attosecond driving lasers move rapidly towards long-wavelength infrared, high pulse energy and high average power, one can envision high flux compact coherent X-ray sources, time-resolved X-ray spectroscopy, X-ray circular dichroism instruments for spin and handedness measurements that lead all the way up to the hard X-ray. To generate attosecond X-rays in the 1 to 5 keV photon energy range, we propose to develop a high power long-wavelength infrared attosecond driving laser based on Optical Parametric Chirped Pulse Amplification, which delivers 25 fs (single-cycle), carrier-envelope phased stabilized, 5 mJ pulses centered at 8 micron with a 2 kHz repetition rate. The optical parametric crystal, Zinc Germanium Phosphide (ZnGeP2 crystals), for amplifying the infrared signal will be pumped by a home-build Ho:YLF laser. The DURIP funds will be used to purchase 8 high power (120 W) Tm:fiber lasers, and three high cooling power (180 W) cryogenic cooling units. The high energy Ho:YLF laser will be powered by the high power Tm:fiber lasers. The heat in the Ho:YLF gain medium will be effectively removed by the cryogenic cooling units. The ability to broadly proliferate femtosecond and attosecond hard X-ray sources at the laboratory-scale can have a profound impact on science and technology. The understanding and control of materials that will result, based on innovative ultrafast X-ray investigations, will revolutionize DoD s ability to make advances in electronic devices, energetic and novel materials, memory storage, and on-site energy production, among the many possible benefits.?
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Mar 21, 2019
- Source ID
- W911NF1910224
Entities
People
- Zenghu Chang
Organizations
- Army Contracting Command
- United States Army
- University of Central Florida