Tuesday afternoon | 23 June 2026
In‑situ intensity measurements for multi‑petawatt lasers are all about verifying the electromagnetic field strength directly at the laser focus, rather than relying on indirect diagnostics upstream. At these extreme intensity levels, even tiny uncertainties in beam quality, wavefront distortion, or target alignment can shift the actual on‑target intensity by orders of magnitude from the one determined indirectly.
Researchers use techniques such as plasma‑based probes, secondary‑emission signatures, ionization levels, electron scattering, CTR etc. to infer the focal intensity without placing fragile optics in the beam. The goal is to capture the true interaction conditions at 1022–1024 W/cm2, where conventional sensors would be destroyed instantly. As multi‑PW systems become more common, these in‑situ methods are becoming essential for validating experiments, benchmarking simulations, and ensuring that the laser is delivering the extreme fields that strong field physics demands.
The purpose of the workshop could be to set up a small working group investigating possible measurement approaches and develop a comprehensive experimental setup for cross-calibration of the various methods proposed by the high-intensity community. Most likely dedicated simulation work also needs to take place to have a detailed understanding of the possible signatures. Subsequently one would apply for dedicated beamtime on multi-PW laser installations (including L4f at ELI-Beamlines) to perform the corresponding experiments.
Agenda
12:00 - 13:00 | Lunch
13:00 - 13:20 | Michael Ehret, ELI-Beamlines - Czechia, The multi-PW infrastructure @ ELI-BL: status & commissioning
13:20 - 13:40 | Antonino DiPiazza, University of Rochester/LLE - USA, Peak intensity measurement of relativistic lasers via nonlinear Thomson scattering
13:40 - 14:00 | Alexander Pirozhkov, KPSI-QST - Japan, Approaching the physical limits of petawatt-laser intensity: tuning challenges, error sources, and best practices
14:00 - 14:20 | Robert Fedosejevs, University of Alberta - Canada, Ponderomotive acceleration of electrons as a signature of peak focal spot intensity
14:20 - 14:40 | Arseny Mironov, CPhT-CNRS - France, Ionization-based diagnostics for extreme light fields
14:40 - 15:00 | Petru Ghenuche, ELI-NP - Romania, On-shot intensity measurement with 10 PW laser beam at ELI-NP
15:00 - 15:20 | Shirui Xu, Peking University - China, Optimization of ultraintense laser focus utilizing far-field patterns of second-order harmonics from laser-foil interaction
15:20 - 15:50 | Coffee Break
15:50 - 17:00 | Round Table Discussion
- ONLINE participation might be possible but still requires registration.
- No registration fee.
- Lunch & coffee for registered participants
- The workshop will consist of a few invited talks, followed by a round-table discussion.
- Contact person: Evgeny Gelfer, evgeny.gelfer@eli-beams.eu
