As major milestone of commissioning phase of beam transport section for the 10 PetaWatts beamlines of Extreme Light Infrastructure Nuclear Physics (ELI-NP) located in Magurele (Romania), we have propagated the beam throughout the beam transport section and measured its energy as well as its pulse duration after compression at full energy and full aperture. 10 consecutive laser pulses have been shot at a repetition rate of 1 shot per minute with compressed pulse energy ranging between 241 and 246 Joules while pulse duration has been measured at 23 fs leading to the first ever operation above 10 PetaWatts peak power
We report the generation of unprecedented 10 PetaWatt laser pulses obtained from each of the two beamlines of the High Power Laser System (HPLS) of ELI-NP (Extreme Light Infrastructure – Nuclear Physics) research infrastructure. The laser system is a hybrid system made of a double CPA based on amplification within Titanium Sapphire crystals combined with an OPCPA with a parametric amplification stage boosting the energy to 10 mJ at the entrance of the second CPA. A XPW filter is also inserted between the two CPA and in combination with the OPCPA improves the temporal contrast of the pulses by typically 7 orders of magnitude. The spectral effects occurring during amplification such as gain narrowing and wavelength shifting are compensated through the use of spectral filters. Final amplification stages are involving large aperture Ti:Sapphire crystals (up to 200 mm) which are pumped by high energy frequencydoubled Nd:Glass lasers delivering each 100 J of green light. Laser beams have been amplified respectively up to 332 J and to 342 J of pulse energy at 1 shot per minute without any occurrence of ASE and transverse lasing thanks to index matching fluid surrounding the crystal over is entire length and pump deposition management over the time before each beam pass within the Ti:Sapphire crystal. We have demonstrated full aperture compression by metric gratings of these amplified pulses down to 22.6 fs and therefore made the full demonstration for the first time ever of 10 PW capability from a laser system.
Based on ChemCam/SuperCam heritage, a laser with improved performances is built on a table top set-up. The optical configuration is implemented into new lasers proposed for next generation of LIBS – Raman instruments.
The XCAN project aims at the coherent combination of 61 fiber amplifiers in the femtosecond regime. An important intermediate step towards this goal is the implementation of a seven fiber test setup, which allows to address key scientific and technical challenges which might occur in the scaled version of 61 fibers. This work includes the design and characterization of a support unit able to hold 61 fibers with the high precision required for an efficient coherent combination in tiled aperture configuration. This configuration, in combination with an interferometric phase measurement and active phase control, is particularly well suited for the coherent combination of a very large number of beams. Our first preliminary results with seven fibers include a combination efficiency of 30 % and a residual phase error between two fibers as low as λ/40 rms. Experiments conducted with three fibers in order to evaluate technical improvements revealed an increase of efficiency to 54 %. The combined beam was temporally compressed to 225 fs, which is Fourier transform limited with respect to the measured spectrum.
A new conduction cooled compact laser for laser induced spectroscopy on the Mars Science Laboratory (MSL) to be launched in 2009 is presented. An oscillator combined to amplifiers generates 30mJ at 1μm with a good spatial quality. Development prototype of this laser has been built and characterized. Environmental testing of this prototype is also reported.
A new conduction cooled compact laser for SuperCam LIBS-RAMAN instrument aboard Mars 2020 Rover is presented. An oscillator generates 30mJ at 1µm with a good spatial quality. A Second Harmonic Generator (SHG) at the oscillator output generates 15 mJ at 532 nm. A RTP electro-optical switch, between the oscillator and SHG, allows the operation mode selection (LIBS or RAMAN). Qualification model of this laser has been built and characterised. Environmental testing of this model is also reported.
The development of coherent light sources with emission in the mid-IR is currently undergoing a remarkable revolution. The mid-IR spectral range has always been of tremendous interest, mainly to spectroscopists, due to the ability of mid-IR light to access rotational and vibrational resonances of molecules which give rise to superb sensitivity upon optical probing [1-3]. Previously, high energy resolution was achieved with narrowband lasers or parametric sources, but the advent of frequency comb sources has revolutionized spectroscopy by providing high energy resolution within the frequency comb structure of the spectrum and at the same time broadband coverage and short pulse duration [4-6]. Such carrier to envelope phase (CEP) controlled light waveforms, when achieved at ultrahigh intensity, give rise to extreme effects such as the generation of isolated attosecond pulses in the vacuum to extreme ultraviolet range (XUV) [7]. Motivated largely by the vast potential of attosecond science, the development of ultraintense few-cycle and CEP stable sources has intensified [8], and it was recognized that coherent soft X-ray radiation could be generated when driving high harmonic generation (HHG) with long wavelength sources [9-11]. Recently, based on this concept, the highest waveform controlled soft X-ray flux [12] and isolated attosecond pulse emission at 300 eV [13] was demonstrated via HHG from a 1850 nm, sub-2-cycle source [14]. Within strong field physics, long wavelength scaling may lead to further interesting physics such as the direct reshaping of the carrier field [15], scaling of quantum path dynamics [16], the breakdown of the dipole approximation [17] or direct laser acceleration [18]. The experimental development of long wavelength light sources therefore holds great promise in many fields of science and will lead to numerous applications beyond strong field physics and attosecond science.
In this paper, we present results about a high energy picosecond Holmium YLF laser developed in order to be used as the puming laser for the first mid-IR optical parametric chirped pulse amplifier (OPCPA) operating at a center wavelength of 7 μm with output parameters suitable already for strong-field experiments. It is also the first demonstration of an Optical Parametric Chirped Pulse Amplifier (OPCPA) using a 2 μm laser pump source which enables the use of nonoxide nonlinear crystals with typically limited transparency at 1 mm wavelength. This new OPCPA system is alloptically synchronized and generates 0.2 mJ energy, CEP stable optical pulses. The pulses are currently compressed to sub-8 optical cycles but support a sub-4 cycle pulse duration. The discrepancy in compression is due to uncompensated higher order phase from the grating compressor which will be addressed in the future.
The XCAN project, which is a three years project and began in 2015, carried out by Thales and the Ecole Polytechnique aims at developing a laser system based on the coherent combination of laser beams produced through a network of amplifying optical fibers. This technique provides an attractive mean of reaching simultaneously the high peak and high average powers required for various industrial, scientific and defense applications. The architecture has to be compatible with very large number of fibers (1000-10000). The goal of XCAN is to overcome all the key scientific and technological barriers to the design and development of an experimental laser demonstrator. The coherent addition of multiple individual phased beams is aimed to provide tens of Gigawatt peak power at 50 kHz repetition rate.
Coherent beam combining (CBC) of fiber amplifiers involves a master oscillator which is split into N fiber channels and then amplified through series of polarization maintaining fiber pre-amplifiers and amplifiers. In the so-called tiled aperture configuration, the N fibers are arranged in an array and collimated in the near field of the laser output. The N beamlets then interfere constructively in the far field, and give a bright central lobe. CBC techniques with active phase locking involve phase mismatch detection, calculation of the correction and phase compensation of each amplifier by means of phase modulators. Interferometric phase measurement has proven to be particularly well suited to phase-lock a very large number of fibers in continuous regime. A small fraction of the N beamlets is imaged onto a camera. The beamlets interfere separately with a reference beam. The phase mismatch of each beam is then calculated from the interferences’ position. In this presentation, we demonstrate the phase locking of 19 fibers in femtosecond pulse regime with this technique.
In our first experiment, a master oscillator generates pulses of 300 fs (chirped at 200 ps). The beam is split into 19 passive channels. Prior to phase locking, the optical path differences are adjusted down to 10 μm with optical delay lines. Interferograms of the 19 fibers are recorded at 1 kHz with a camera. A dedicated algorithm is developed to measure both the phase and the delay between the fibers on a measurement path. The delay and phase shift are thus calculated collectively from a single image and piezo-electric fiber stretchers are controlled in order to ensure compensation of time-varying phase and delay variations. The residual phase shift error is below λ/60 rms. The coherent beam combining is obtained after propagation and compression. The combined pulse width is measured at 315fs. A second experiment was done to coherently combine two amplified channels of the XCAN demonstrator. A residual phase shift error of λ/30 rms was measured in this case.
The development of coherent light sources with emission in the mid-IR is currently undergoing a remarkable revolution. The mid-IR spectral range has always been of tremendous interest, mainly to spectroscopists, due to the ability of mid-IR light to access rotational and vibrational resonances of molecules which give rise to superb sensitivity upon optical probing [1-3]. Previously, high energy resolution was achieved with narrowband lasers or parametric sources, but the advent of frequency comb sources has revolutionized spectroscopy by providing high energy resolution within the frequency comb structure of the spectrum and at the same time broadband coverage and short pulse duration [4-6]. Such carrier to envelope phase (CEP) controlled light waveforms, when achieved at ultrahigh intensity, give rise to extreme effects such as the generation of isolated attosecond pulses in the vacuum to extreme ultraviolet range (XUV) [7]. Motivated largely by the vast potential of attosecond science, the development of ultraintense few-cycle and CEP stable sources has intensified [8], and it was recognized that coherent soft X-ray radiation could be generated when driving high harmonic generation (HHG) with long wavelength sources [9-11]. Recently, based on this concept, the highest waveform controlled soft X-ray flux [12] and isolated attosecond pulse emission at 300 eV [13] was demonstrated via HHG from a 1850 nm, sub-2-cycle source [14]. Within strong field physics, long wavelength scaling may lead to further interesting physics such as the direct reshaping of the carrier field [15], scaling of quantum path dynamics [16], the breakdown of the dipole approximation [17] or direct laser acceleration [18]. The experimental development of long wavelength light sources therefore holds great promise in many fields of science and will lead to numerous applications beyond strong field physics and attosecond science. In this paper, we present the first mid-IR optical parametric chirped pulse amplifier (OPCPA) operating at a center wavelength of 7 μm with output parameters suitable already for strong-field experiments. It is also the first demonstration of an Optical Parametric Chirped Pulse Amplifier (OPCPA) using a 2 μm laser pump source which enables the use of non-oxide nonlinear crystals with typically limited transparency at 1 mm wavelength. This new OPCPA system is all-optically synchronized and generates 0.55 mJ energy, CEP stable optical pulses. The pulses are currently compressed to sub-8 optical cycles but support a sub-4 cycle pulse duration. The discrepancy in compression is due to uncompensated higher order phase from the grating compressor which will be addressed in the future.
A laser system made of two beams of 10 PW each has been designed and is currently built for ELI-NP research infrastructure. Design is presented as well as preliminary results up to the 1PW level amplifier.
O. Chalus, A. Pellegrina, S. Ricaud, O. Casagrande, C. Derycke, C. Radier, A. Soujaeff, G. Matras, G. Rey, L. Boudjemaa, C. Simon-Boisson, S. Laux, F. Lureau
A hybrid Ti:Sa CPA/BBO OPCPA system with a XPW filter in between the two has been developed to produce a broadband high contrast seeder of 10 mJ for the two 10 PetaWatt beamlines of ELI NP infrastructure.
We have obtained 23 J uncompressed laser pulses at a repetition rate of 1 Hz with a spectral width of 41 nm FWHM
which could produce 600 TW if compressed ; this is the highest energy obtained to date from a Titanium Sapphire
amplifier working at a such repetition rate. This amplifier is part of a 1.3 PW laser system under construction by Thales
Optronique for the BELLA project of LBNL aiming laser wakefield acceleration of electrons up to 10 GeV.
We report on an experimental investigation of the noise properties of an free-running, high-power, picosecond Nd:YVO4 oscillator pumped by a 100 W laser diode. The amplitude noise has been measured with a photodiode and an electronic
spectrum analyser, and then compared with other mode-locked oscillator's noise spectrum. We show that in terms of
noise properties, our powerful oscillator is comparable with low-power oscillators such like low-noise Ti:Sapphire
oscillators. We also show that the frequency doubling does not affect the amplitude noise of the oscillator. High power
diode pumping is then not an issue to get low-noise high-power oscillators.
We report on a high-power, passively mode-locked, TEM00 Nd:YVO4 oscillator with adjustable pulse duration between
46 and 12ps. The laser is end-pumped by an 888nm laser diode and mode-locking is achieved with a semiconductor
saturable absorber mirror (SESAM). The laser has a repetition rate of 91MHz and the M2 beam quality factor is better
than 1.2 at 15ps. At the optimum output coupler, it provides a maximum average output power of 45W with 32ps pulse
duration. In literature, the presence of spatial hole burning (SHB) often helps to shorten the pulse length down to few
picoseconds. However, SHB might be an issue for some specific application requiring e.g. low noise picosecond
oscillators. In this contribution, we demonstrate that it is possible to shorten the pulse duration by lowering the
intracavity losses without SHB. Pulse tunability from 46 to 12ps is achieved by changing the output coupler of the cavity
while staying in the continuous-wave mode-locked regime. Pulse duration is almost linear with the output coupler
transmission and increases from 12 to 32ps with average output power ranging from 15 to 45W. In this range of output
power, we demonstrate the shortest pulses directly from a Nd:YVO4 oscillator.
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