GHz Frame-Rate Laser Diagnostics of HED Plasmas for 10 Hz LaserNetUS Facilities

Studies of laser-driven high energy density (HED) plasma physics require large, complex laser systems providing well-controlled pulses at extreme intensities reaching TW and PW levels. New facilities, several of which exist within the LaserNetUS consortium, have increased the operation rate of 10-100 TW laser sources to the 10 Hz regime, allowing thousands of HED experiments to be performed within minutes. The ability to collect large data sets will enable more thorough and robust data analysis, particularly by leveraging machine learning and artificial intelligence techniques. However, high fidelity HED plasma diagnostics are required at commensurate repetition rates to realize the full research potential of these facilities. While several plasma diagnostic techniques with high temporal resolution exist at 10 Hz, these methods are unable to temporally characterize a single HED plasma event. Since HED plasma diagnostics take place on ps – ns time scales, imaging techniques with GHz frame rates are required to track the evolution of HED plasmas; frame gating on the single ps level is also necessary to freeze plasma movement withing a single frame. The proposed imaging technique maintains ps-level temporal resolution while simultaneously capturing 2D plasma dynamics on 100 ps timescales. Furthermore, while the current proposal supports 10 Hz delivery of GHz imaging bursts, this delivery rate is only limited by the operation of the TW and PW lasers within the LaserNetUS network. Scaling delivery to kHz levels is possible through straightforward modifications of the laser probe source. Spectral Energies will leverage its industry leading laser diagnostics capabilities to develop a compact, turn-key system suitable for deployment at LaserNetUS facilities and future commercialization efforts. Dr. Enam Chowdhury at the Ohio State University will lead the implementation of the GHz frame rate HED plasma imaging source. His ultrafast laser laboratory will initially demonstrate the system’s spatial and temporal resolution using laser generated plasmas with densities sufficient for comparison with those generated at multi-TW HED laboratories. Aside from the direct benefit to the Department of Energy related to GHz rate imaging of HED laser plasmas, this technology offers several robust commercialization pathways. There is significant potential for market adoption within the cold ablation and precision laser processing industry, particularly the multi-billion dollar optical display market that calls for low-heat laser cutting, etching, and marking. Precision laser machining is enabled by products identical to the laser proposed here: ultrafast pulse durations (precision, athermal material modification) at high-repetition rates (GHz) with tunable burst formats (advanced thermal mitigation). In addition to the commercial potential within the industrial sector, the source developed here will likely receive research funding and commercial sales from academic and government laboratories. SE’s well-established partnerships with government laboratories will be strengthened with this new diagnostic research tool, particularly relative to hypersonic imaging and measurements of rotating detonation engines.