Welcome to the Ultrafast Atomic, Molecular & Plasma Research Group at UCF!
We aim to investigate charge dynamics in atoms, molecules and plasmas during and post photo-interactions with ultrafast laser pulses. We study the photo-response of matters at a microscopic level – “visualize” the motion of fundamental elements, such as electrons and ions at their natural time scales, attosecond (10-18sec) for electrons and femtosecond (10-15sec) for ions.
In this research, we implement ultrafast and high power lasers, and electron and ion spectroscopy as the main method. Responding to the strong-field of the laser pulses, particle systems can absorb enormous photo-energy which converts into other energy forms – chemical energy, internal electronic energy, kinetic energy of fragments. The goal is to create a movie of the particle dynamics to illustrate the evolution of the particle system and energy flow induced by photo-absorption.
In addition to the research within the laboratory on campus, we will also carry out or participate in experiments, typically in collaboration with other institutes, at free-electron-laser facilities around the world. Free-electron lasers can deliver ultra-intense femtosecond pulses in the x-ray regime.
Title video (computer version): From a fiber optic projector show, named “Dimension,” taken at the Zeiss Planetarium at Jena Germany this summer (2019). It beautifully demonstrates a view of transition from the macro-world – what we see by naked eyes, the clouds and buildings, to the micro-world – what we “see” through scientific instruments and methods, the fundamental elements of matters – molecules and atoms, ions, and electrons. In this laboratory, we investigate the dynamics of these fundamental elements in responses of matters to lights, at their natural spatial and temporal level.
The electron and ion motion during and post photointeraction is of attosecond and femtosecond timescale respectively. We investigate photo-induced electron and ion dynamics and hence the energy absorption and redistribution at their natural time scales. Ultrashort laser pulses are applied to initiate and probe the dynamics to reveal the electronic and kinetic evolution of the target system – a fundamental aspect of photo-interaction. Monitoring both of the electron and ion motion simultaneously allows us to investigate the correlation between electronic and nuclear dynamics.
Plasmas as the fourth state of matter consist of positive and negative charges and can contain a large amount of energy. We generate plasmas in nano-size particles using laser pulses and investigate the energy exchange between the electrons and ions along with the expansion of the plasma. These plasmas bestowed with photo-energy give rise to highly energetic electrons and ions. We aim to understand absorption and energy dissipation mechanisms at different photon energy regimes and their structural and geometrical dependence.
Free-electron lasers deliver very bright x-ray pulses of femtosecond durations. X-rays can access the most inner shell of light atomic element, making the spectral features atomic-species specific. The subsequent ionization and excitation processes are also unique phenomena in photointeraction. We develop core-hole spectroscopy and investigate charge dynamics induced by core- and inner-shell ionization and their secondary processes. Experiments are carried out at large facilities off the UCF campus, typically with a collaboration with other institutes within or outside the US.
The lab will be equipped with:
- Main laser system: 1 micrometer wavelength, High average power (100 W at 330 fs) and high repetition rate (200 kHz) fiber laser system. Final stage <10 fs pulse duration, 45W (delivered in May 2021)
- Secondary light sources: Extreme ultraviolet (XUV) laser of short pulse duration generated via high harmonic generation processes
- COLTRIMS-type double-sided electron and ion spectrometer system for simultaneous 3-D or 2-D momentum imaging of electrons and ions
Lab B (UFAST):
- Main laser system: 2 micrometer wavelength, High average power (200 W at 200 fs output) and high repetition rate (100 kHz) fiber laser system. Final stage 12 fs (<2-cycle) pulse duration, 120W (to be delivered in Jan. 2023)
- Secondary light sources: attosecond soft x-ray (water window) pulses, attosecond XUV pulses, few-cycle long-wavelength infrared pulses, single cycle THz pulses
- Double sided VMI, reflective transient absorption (in collaboration), HHG in solids (in collaboration)
Research in my group will provide opportunities for hands-on experience with high power ultrafast lasers and spectroscopy methods and opportunities for deep understanding of the involved laser technology, scientific approach, physics fundamentals that lead to interdisciplinary applications. In addition to the in-house research at UCF, we also carry out and participate research projects at national laboratories and international facilities.Open positions