We are interested at a fundamental level in the processes that occur when light of extreme intensities interacts with matter to create high energy density plasma. These effects are relevent in all potential applications of ultra-short pulse laser systems.
High-repetition rate Petawatt-Class Laser Design
Currently we have a 40 TW peak power 10 Hz laser producing 25 femtosecond pulses with 1.1 Joules/pulse with a center wavelength of 810 nm. We are in the process of upgrading the system to a 0.5 petawatt laser with 1 shot per minute repetition rate. For on-shot laser diagnostics, we have a SPIDER, scanning auto-correlator, high dynamic range third-order cross-correlator and various other diagnostics.
Development of High Repetition-Rated Diagnostics and Laser Intensity Characterization Techniques
The measurement of peak intensities and pulse shape in ultra-short, ultra-intense laser systems has traditionally been difficult to ascertain. This presents difficulties when trying to model and compare experimental data to theory. A major goal of our science is to develop reliable techniques to more accurately measure these parameters.
X-ray sources for radiography
Since laser pulse output can be synchronized with external mechanical processes, ultra-intense laser systems can be used as x-ray sources in industrial imaging applications. As an example, test engineers can use this to their advantage when they examine aircraft turbine blades for mechanical stress failures.
Proton & Light Ion Micro-acceleration
The production of highly energetic protons and ions can be enhanced by ultra-intense lasers. Conventional accelerator technologies are both cost- and size-prohibitive. It is hoped that by using laser-based technologies, accelerators will become more accessible to researchers and end-users. With ultra-intense lasers, we can create acceleration gradients with electric fields on the order of MV/micron, or 1012 V/m. This is 1,000 times larger than the current state-of-the-art. For comparison, lightning bolts have associated fields of around 105 V/m, and the electric field between the proton and the ground state electron of the hydrogen atom is only 1012 V/m. Better accelerators will make less-invasive medical imaging and treatment methods used in oncology more ubiquitous, and will facilitate the study of high-energy particle and astro-particle physics, including supernovae studies.
While x-rays are useful for imaging metallic materials, compact, short-pulse laser-based neutron sources could provide for enhanced scans of plastics and other low density materials, for use in industrial and defense applications (e.g. screening for plastic explosives). In this case, the laser system serves as a catalyst for neutron production in the target material by generating micro-fusion reactions.
Novel Target Structure Fabrication
Laser-target energy coupling is dependent on the characteristics of the target material. To extract the most energy possible out of a laser pulse, targets must be optimized. We are researching ways to improve this efficiency.
High-Throughput Automation & Control Systems
In order to obtain large data sets for better physical analysis, laser laboratories need to implement target positioning and laser synchronization hardware and software based on machine automation. We are exploring the design of control systems in order to achieve this.
Electron Transport in Fast Ignition Targets
The key to fast ignition fusion is delivering a sufficient amount of energy to the fuel core of the target in order to spark ignition, by using short-pulse laser light. When this light impinges on the target, approximately 20% of the energy goes into hot electron propagation, which carries the energy into the core of the fuel. Electrons with energies of 1-2 MeV have significant interactions with matter at hundreds of times solid density, as is experienced in compressed fuel targets.
Laser-induced Nuclear Reactions
Aside from their use in fast ignition fusion studies, ultra-short lasers are capable of inducing nuclear fission reactions in materials. This technology can be combined with radiation detector hardware in order to build a spectroscopic analysis system.