The technique of chirped pulse amplification has conveniently enabled the development of Joule-class laser facilities delivering terawatt levels of power with a single shot beam on target. In powerful systems like these, beam metrology for pulse charaterization is crucial for maintaining a high level of confidence in generating high intensity laser shots. Optical diagnostics for monitoring beam features such as spectra, beam profile, energy and also measuring dispersion and the compressed pulse duration are necessary. Spatio-temporal couplings such as angular dispersion caused by the presence of chromatic aberrations can distort the pulse energy and duration on target and affect laser matter interactions. A pulsefront- tilt (PFT) diagnostic utilizing a diffractive optic for determining angular dispersion and misalignment at shorter bandwidths is designed and implemented for our laser facility, along-with a homemade single shot auto-correlator for measuring pulse duration after the grating compressor. For real-time monitoring of the laser facility, a smart dashboard protocol using openBIS ELN (Electronics Lab Notebook) is administered to enable regular and uninterrupted saving of raw data which is integrated into the local dashboard for visualization and data analysis.
Empulse is the Swiss table-top near-infrared (λ = 1050 nm) laser system that aims to produce 10-TW class pulses through chirped pulse amplification. The system offers a flexible platform for a number of experiments in materials science, such as advanced spectroscopy and/or materials under extreme conditions. The technical design report (TDR) is presented, highlighting the system architecture and performance. This TDR gives a general overview of the Empulse system and updates on developments towards realization of a joule-class ∼ps-scale short pulse output. In particular, the laser system timing diagram, safety interlock scheme, the front-end pulse jitter characterization, and finally the group delay dispersion (GDD) calculations of the stretcher and compressor optics are presented. The system is complemented by a number of dedicated diagnostics and realtime-monitoring, as reported in the paper by Hemani et al. in this proceedings.
Design and development of a compact chirped pulse amplification (CPA) laser is presented. This system will be used to generate coherent tabletop X-rays based on laser-produced plasmas (LPP) for round the clock advanced spectroscopy. The building blocks of the laser are shown and the results from the front-end are laid out. The progress on the amplification stages is presented with a scheme to extract compressed 15 J laser pulses at the output which are to be characterized and hit on rotating target for generating a plasma with enough population inversion (Ne-like or Ni-Like) as such to enable the emission of Soft X-rays. Soft X-rays laser lines from different targets will be characterized and used for different spectroscopy experiments.
Nanosecond laser pulses can be controlled using fast electronics and fast EOM modulators. Its usefulness has been proven in high density plasma physics, avoidance of Brillouin scattering, laser peening, laser amplification in OPCPA among others.
We present an active feedback loops between the end of a regenerative amplifier and the arbitrary waveform generator that modulates its seed. We explore several algorithms and several pulse shapes, exploring the difference between them and the optimal parameters for each, finding a robust solution. The method applied here can be used to obtain any pulse shape.
The Vulcan laser has been a tool to preform high energy plasma physics, including among others laboratory astrophysics and particle acceleration. The Petawatt laser beamline/target area is now going to be updated with a new beamline. This new beamline is going to be entirely set upon OPCPA as an amplification technique, and will primarily be dedicated to betatron imaging.
This laser will be used at the same time as a 600 J, PW beamline, a 250J ns beam and a kJ ns long pulse.
Overall we present a PW class OPCPA system comparable with Ti:sapphire laser PW systems, 30J, sub-30fs pulses.
The Petawatt beamline at the Vulcan laser facility is capable of delivering pulses with 500J of energy in <500fs, and has been operational as a user facility since 2003; being used to study laser matter interactions under extreme conditions. In addition to this short-pulse beamline there is a single long pulse beamline capable of 250J with durations from 0.5 to 6ns. In this paper we present our plans to add an auxiliary beamline to this facility based on Optical Parametric Chirped Pulse Amplification (OPCPA) using LBO as the non-linear crystal. This new beamline will have a dedicated laser area where the seed will be generated, stretched and amplified before being transported to the target area for compression and delivery to target. The beamline will be implemented in 2 phases the first phase will see the development of a 7J <30fs capability with the second phase increasing the delivered energy to 30J. This additional beamline will open up the potential for novel pump probe experiments when operated with the existing PW and long pulse beamlines.
KEYWORDS: Optical amplifiers, Picosecond phenomena, Near field optics, Mirrors, Diagnostics, Near field, Silicates, Pulsed laser operation, Glasses, High power lasers
We present details of a refurbishment and development programme that we have undertaken on the Vulcan Nd:Glass laser system to improve delivery to its two target areas. For target area petawatt in addition to replacing the gratings in the compressor chamber we have installed a new diagnostic line for improved pulse length measurement and commissioned a high energy seed system to improve contrast. In target area west we have replaced a grating on the high energy short pulse line and improved the focal spot quality. Both areas have been re-commissioned and their laser parameters measured showing that the pulse in petawatt has been measured below 500fs and focused to a spot size of 4μm the two short pulse beam lines in target area west have been measured as short as 1ps and have been focused to 5μm.
Here we present recent progress from the new CLF
Adaptive Optics program including a new development laboratory
and tests of a high damage threshold dielectric deformable mirror.
The recently refurbished laboratory has versatile optical layout,
multi wavelength, large beam diameter and large propagation
distance (~10 m) for testing deformable mirrors up to 150 mm
diameter, as well as manufacturing capabilities.
The achievement of high contrast, high efficiency OPCPA systems has been a long established goal. We achieve close to
~20% conversion in a picosecond OPCPA system. This is now the standard seed for our petawatt pre-amplifier laser
system which had a conventional 108 nanosecond gain. We thereby eliminate the need to the first nanosecond gain stage.
We achieve a contrast at the 10-8 level when using the petawatt system in this configuration. We have also demonstrated
a second stage of picosecond amplification with an extra gain of >2, maintaining the bandwidth and transform limited
nature of the pulses, providing the potential for further improvements.
In this work we perform a simulation study for yttrium calcium oxyborate (YCOB) as the nonlinear medium for optical
parametric amplification. These results will be used to design a new large bandwidth, 10 Hz, OPCPA stage at the
Laboratory for Intense Lasers at IST, pumped by an ytterbium-based amplifier and seeded by a white light continuum.
Different regimes are tested to assess the scalability of the material
L. Volpe, D. Batani, B. Vauzour, Ph. Nicolai, J. Santos, F. Dorchies, C. Fourment, S. Hulin, C. Regan, F. Perez, S. Baton, M. Koenig, K. Lancaster, M. Galimberti, R. Heathcote, M. Tolley, Ch. Spindloe, P. Koester, L. Labate, L. Gizzi, C. Benedetti, A. Sgattoni, M. Richetta
Generation of high intensity and well collimated multi energetic proton beams from laser-matter
interaction extend the possibility to use protons as a diagnostic to image imploding target in Inertial
Confinement Fusion experiments. An experiment was done at the Rutherford Appleton Laboratory
(Vulcan Laser Petawatt laser) to study fast electron propagation in cylindrically compressed targets,
a subject of interest for fast ignition. This was performed in the framework of the experimental road
map of HiPER (the European High Power laser Energy Research facility Project). In the experiment,
protons accelerated by a ps-laser pulse were used to radiograph a 220 m diameter cylinder (20 m wall,
filled with low density foam), imploded with 200 J of green laser light in 4 symmetrically incident
beams of pulse length 1 ns. Point projection proton backlighting was used to get the compression
history and the stagnation time. Detailed comparison with 2D numerical hydro simulations has
been done using a Monte Carlo code adapted to describe multiple scattering and plasma effects
and with those from hard X-ray radiography. These analysis shows that due to the very large mass
densities reached during implosion processes, protons traveling through the target undergo a very large
number of collisions which deviate protons from their original trajectory reducing proton radiography
resolution. Here we present a simple analytical model to study the proton radiography diagnostic
performance as a function of the main experimental parameters such as proton beam energy and target
areal density. This approach leads to define two different criteria for PR resolution (called "strong"
and "weak" condition) describing different experimental conditions. Finally numerical simulations
using both hydrodynamic and Monte Carlo codes are presented to validate analytical predictions.
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