System
Capabilities
The proposed NSF OPAL parameters and capabilities significantly extend the current state of the art in ultrahigh peak power, ultrafast lasers and will serve national and international research communities for decades to come.
The laser design effort establishes system requirements and designs for generating two 25 PW Alpha beams and delivering them in various configurations to two independent experimental areas (EA1 and EA2). This effort includes developing requirements and concepts for focusing each of these beams to produce on-target intensities of ~5⨉1023 W/cm2, co-timing of the beams to ~10 fs rms, and co-pointing to approximately 1.5 µm rms. Alternative focusing geometries, on-target pulse width adjustment, and the generation of a separate Beta beamline are also included in the design effort. System-wide budgets developed for energy, wavefront, centering, pointing, spectrum, dispersion management, and timing jitter will ensure that the laser system meets all experimental requirements.
The Beta beam will be designed to provide a lower peak-power pulse that is co-timed with an Alpha beam. The design effort will develop a separate path from the output of NOPA-J that will be capable of providing a beam at up to 2.0 PW to either experimental area, and will include the ability to independently control the energy, pulse width, focusing, and timing with respect to an Alpha beam.
Additionally, all four of the OMEGA EP beams will be transported to the new NSF OPAL building. The current OMEGA EP infrared beam transport structures will be modified to include a configuration to direct the beams to the NSF OPAL facility where they will be converted to UV for use as compression beams.
| Parameter | Performance | Comments |
| Intensity (Power) | 5⨉1023 W/cm2 (25 PW) | Final performance with all parameters optimized |
| Energy on Target (max.) | 500 J | State-of-the-art gratings, with 2.4x margin (max-mean fluence) |
| Beam FW1% after compressor | 86 x 86 cm2 | Baseline design for full-scale performance, which requires scaling grating production |
| Shot cycle time (min.) | 5 minutes | Requirement for ACoDA modules |
| Pulse width (min.) | 20 fs (FWHM) | Fourier limit = 17 fs Temporal Strehl = 0.80 |
| Temporal contrast (max.) | ~1⨉1011 before -5 ps with respect to pulse | Based on expected performance of Multi-Terawatt (MTW) OPAL with double plasma mirror |
| Pulse co-timing | 10 fs (rms) | Relative timing of Alpha and/or Beta pulses at target-chamber center |
| Focal spot FWHM (f/2) | 2.3 µm at best focus | Diffraction limit = 2.0 µm Spatial Strehl = 0.65 |
| Polarization | Linear or circular polarization | Details of which polarizations will be available in which target areas are TBD |
| Co-pointing precision (Alpha to Alpha) | 1.5 µm (rms) | Relative focus locations of Alpha beams at target |
| Parameter | Performance | Comments |
| Intensity (Power) | 2.3⨉1019 W/cm2 (2.0 PW) | Intensity depends on focusing geometry |
| Energy on Target (max.) | 20 J | State-of-the-art gratings, with 2.4x margin (max-mean fluence) |
| Shot cycle time (min.) | 5 mins | Requirement for ACoDA modules |
| f/# range | Variable f/# up to f/45 | Includes focusing schemes with intentional spatiotemporal coupling (i.e., ‘flying focus’) |
| Polarization | Linear | — |
| Parameter | Performance | Comments |
| Energy on Target | Up to 6 kJ per beam at 10 ns | Expect to deliver standard performance achieved on OMEGA EP |
| Pulse Width | 100 ps – 10 ns | |
| Spot Size | 400 μm – 2000 μm | |
| Shot cycle time (min.) | 90 mins |