Showing papers on "Chirped pulse amplification published in 2005"
TL;DR: The 60-beam Omega laser system at the University of Rochester's Laboratory for Laser Energetics (LLE) has been a workhorse on the frontier of laser fusion and high-energy density physics for more than a decade as mentioned in this paper.
Abstract: The 60-beam Omega laser system at the University of Rochester's Laboratory for Laser Energetics (LLE) has been a workhorse on the frontier of laser fusion and high-energy-density physics for more than a decade. LLE scientists are currently extending the performance of this unique, direct-drive laser system by adding high-energy petawatt capabilities.
191 citations
TL;DR: A double chirped-pulse-amplification (CPA) Ti: sapphire laser system that includes two CPA stages with intermediate nonlinear temporal pulse filtering makes it possible to reduce substantially the background of amplified spontaneous emission (ASE), including prepulses and postpulses.
Abstract: We demonstrate a double chirped-pulse-amplification (CPA) Ti: sapphire laser system that includes two CPA stages with intermediate nonlinear temporal pulse filtering. The method makes it possible to reduce substantially the background of amplified spontaneous emission (ASE), including prepulses and postpulses. An ASE temporal contrast of 10(10) was demonstrated at 20 mJ of output energy and 50-fs pulse duration. The demonstrated scheme is applicable to petawatt power-level laser systems.
164 citations
TL;DR: Values of self-phase modulation well in excess of pi can be tolerated for cubicon pulses, allowing for the nonlinear compensation of very large levels of dispersion mismatch between pulse stretcher and compressor.
Abstract: The generation of cubicon pulses from an Yb fiber chirped pulse amplification system at pulse energies up to 200 microJ is demonstrated. After pulse compression 650 fs pulses with a pulse energy of 100 microJ are obtained, where pulse compression relies on the compensation of third-order dispersion mismatch between the stretcher and compressor via self-phase modulation of the cubicon pulses in the fiber amplifier. Values of self-phase modulation well in excess of pi can be tolerated for cubicon pulses, allowing for the nonlinear compensation of very large levels of dispersion mismatch between pulse stretcher and compressor.
146 citations
TL;DR: A significant simplification of the scheme for few-cycle Optical Parametric Chirped Pulse Amplification (OPCPA) is demonstrated which results in the elimination of a picosecond's master oscillator and electronic synchronization loops.
Abstract: We demonstrate a significant simplification of the scheme for few-cycle Optical Parametric Chirped Pulse Amplification (OPCPA) which results in the elimination of a picosecond master oscillator and electronic synchronization loops. A fraction of a broadband seed pulse centered at 760 nm from a 70-MHz Ti:sapphire oscillator was frequency-shifted in a photonic crystal fiber to enable synchronized seeding of a picosecond Nd:YAG pump laser. The seed radiation at 1064 nm is produced in the soliton regime which makes it inherently more intense and stable in comparison with other methods of frequency conversion. The remaining fraction of the Ti:sapphire output is amplified with a FWHM bandwidth of 250 nm in a single timing-jitter-free OPCPA stage. Our work opens up the exciting possibility to use sub-picosecond pump pulses from highly efficient Yb-based amplifiers for jitter-less parametric amplification of carrier-envelope phase stabilized pulses from Ti:sapphire oscillators.
133 citations
TL;DR: The generation of 9.8+/-0.3 fs laser pulses with a peak power exceeding one terawatt at 30 Hz repetition rate is demonstrated, using optical parametric chirped pulse amplification.
Abstract: We demonstrate the generation of 9.8±0.3 fs laser pulses with a peak power exceeding one terawatt at 30 Hz repetition rate, using optical parametric chirped pulse amplification. The amplifier is pumped by 140 mJ, 60 ps pulses at 532 nm, and amplifies seed pulses from a Ti:Sapphire oscillator to 23 mJ/pulse, resulting in 10.5 mJ/pulse after compression while amplified fluorescence is kept below 1%. We employ grating-based stretching and compression in combination with an LCD phase-shaper, allowing compression close to the Fourier limit of 9.3 fs.
116 citations
Patent•
14 Mar 2005
TL;DR: By compensating polarization mode-dispersion as well as chromatic dispersion in photonic crystal fiber pulse compressors, high pulse energies can be obtained from all-fiber chirped pulse amplification systems.
Abstract: By compensating polarization mode-dispersion as well chromatic dispersion in photonic crystal fiber pulse compressors, high pulse energies can be obtained from all-fiber chirped pulse amplification systems. By inducing third-order dispersion in fiber amplifiers via self-phase modulation, the third-order chromatic dispersion from bulk grating pulse compressors can be compensated and the pulse quality of hybrid fiber/bulk chirped pulse amplification systems can be improved. Finally, by amplifying positively chirped pulses in negative dispersion fiber amplifiers, low noise wavelength tunable seed source via anti-Stokes frequency shifting can be obtained.
106 citations
Patent•
14 Mar 2005
TL;DR: In this paper, a modular ultrafast pulse laser system is constructed of individually pre-tested components manufactured as modules, including an oscillator, pre-amplifier and power amplifier stages, a nonlinear amplifier, and a stretcher and compressor.
Abstract: A modular ultrafast pulse laser system is constructed of individually pre-tested components manufactured as modules. The individual modules include an oscillator, pre-amplifier and power amplifier stages, a non-linear amplifier, and a stretcher and compressor. The individual modules can typically be connected by means of simple fiber splices.
92 citations
TL;DR: These pulses represent, to the authors' knowledge, the highest peak power generated from an all semiconductor ultrafast laser system.
Abstract: The concept of eXtreme Chirped Pulse Amplification (X-CPA) is introduced as a novel method to overcome the energy storage limit of semiconductor optical amplifiers in ultrashort pulse amplification. A colliding pulse mode-locked semiconductor laser is developed as a master oscillator and generates 600fs pulses with 6nm bandwidth at 975nm. Using a highly dispersive chirped fiber Bragg grating (1600ps/nm) as an extreme pulse stretcher and compressor, we demonstrate ~16,000 times extreme chirped pulse amplification and recompression generating optical pulses of 590fs with 1.4kW of peak power. These pulses represent, to our knowledge, the highest peak power generated from an all semiconductor ultrafast laser system.
88 citations
75 citations
TL;DR: It is shown that, despite injection seeding, quantum-noise-induced fast modulations of the temporal profile of the pump pulse are imprinted on the spectrum of the amplified chirped pulse and give rise to a large picosecond pedestal in the time domain.
Abstract: We report on direct observation of temporal contrast degradation of short pulses amplified by optical parametric chirped-pulse amplification. We show that, despite injection seeding, quantum-noise-induced fast modulations 50 ps of the temporal profile of the pump pulse are imprinted on the spectrum of the amplified chirped pulse and give rise to a large picosecond pedestal in the time domain.
70 citations
TL;DR: In this article, the status of the PHELIX petawatt laser at the GSI in close collaboration with the Lawrence Livermore National Laboratory (LLNL), and the Commissariat a l'Energie Atomique (CEA) in France is reported.
Abstract: This paper reports on the status of the PHELIX petawatt laser which is built at the Gesellschaft fuer Schwerionenforschung (GSI) in close collaboration with the Lawrence Livermore National Laboratory (LLNL), and the Commissariat a l'Energie Atomique (CEA) in France. First experiments carried out with the chirped pulse amplification (CPA) front-end will also be briefly reviewed.
TL;DR: In this article, a recent experimental campaign to study the interaction physics of petawatt laser pulses incident at relativistic intensities on solid targets was presented, where an extensive suite of optical, x-ray, and particle diagnostics was employed to characterise the processes of laser absorption, electron generation and transport, thermal and K-alpha xray generation, and proton acceleration.
Abstract: We review a recent experimental campaign to study the interaction physics of petawatt laser pulses incident at relativistic intensities on solid targets. The campaign was performed on the 500 J sub-picosecond petawatt laser at the Rutherford Appleton Laboratory. An extensive suite of optical, x-ray, and particle diagnostics was employed to characterise the processes of laser absorption, electron generation and transport, thermal and K-alpha x-ray generation, and proton acceleration.
Journal Article•
TL;DR: DeShazer et al. as discussed by the authors showed that the DKDP crystal is more suitable than the KDP crystal for powerful OPCPA stages in petawatt lasers and developed a laser with 0.4 TW power at a wavelength of 911 nm.
Abstract: The validity of data on the Sellmeier equation [Kirby K. W. DeShazer L. G., JOSA B 4, 1072-1078 (1987)] modified by linearly approximating the dependence of the linear susceptibility on the deuteration level has been verified experimentally. Conditions for broadband optical parametric amplification of chirped pulses in a DKDP crystal at a pump wavelength of 527 nm have been investigated. It is shown that the DKDP crystal is more suitable than the KDP crystal for powerful OPCPA stages in petawatt lasers. Based on a Cr:forsterite laser and optical parametric amplification in the DKDP crystal, a laser with 0.4-TW power at a wavelength of 911 nm has been developed.
TL;DR: It is shown that an ultrashort probe pulse will grow superradiantly, i.e., with an amplitude that scales with the propagation length while contracting self-similarly, which results in very broad-bandwidth amplification due to gain distributed in frequency as well as spatially.
Abstract: A theoretical and numerical investigation of small-signal Raman backscattering from a chirped pump pulse in plasma shows that an ultrashort probe pulse will grow superradiantly, i.e., with an amplitude that scales with the propagation length while contracting self-similarly. These features are commonly associated with the nonlinear stages of Raman amplification in the pump depletion and Compton regimes. We show that the superradiant scaling results in very broad-bandwidth amplification due to gain distributed in frequency as well as spatially. Since different frequencies excite the plasma at different positions, wave breaking is avoided, and prepulses and pedestals are substantially suppressed. Linear chirped pulse amplification in plasma could provide a very broad-bandwidth alternative to solid state laser amplifiers, potentially usable for optical pulses a few cycles in duration.
TL;DR: In this paper, the structural changes that take place in wafer grade silicon when it is micro-machined with ultra-short laser pulses of 150 fs duration were reported.
Abstract: This work reports on the structural changes that take place in wafer grade silicon when it is micro-machined with ultra-short laser pulses of 150 fs duration. A Chirped Pulse Amplification (CPA) Ti:Sapphire laser was used, with an operating wavelength centered on 775 nm and a maximum repetition rate of 1 KHz. The laser induced damage was characterized over the fluence range 0.43–14 J cm-2, and for each fluence a progressively increasing number of pulses was used. The analytical tools used to characterize the samples were all based upon electron microscopy. A 30 KeV scanning transmission electron microscope (STEM) imaging technique was developed to observe defects in the crystal lattice and the thermal-mechanical damage in the area surrounding the laser machined region. Mechanical cross sectioning (in conjunction with Scanning Electron Microscope (SEM) surface imaging) was also used to reveal the internal structure, composition, and dimensions of the laser machined structures. Based on this analysis, it will be shown that laser machining of silicon with femtosecond pulses can produce features with minimal thermal damage, although lattice damage created by mechanical stresses and the deposition of ablated material both limit the extent to which this can be achieved, particularly with high aspect ratios. A key feature of the work presented here is the high-resolution STEM images of the laser-machined structures.
TL;DR: In this article, a two-dimensional extension of a spectral interferometric method called the stationary phase point method is used to determine the frequency dependence of the group delay of a stretcher and a compressive system of a chirped pulse amplification laser.
Abstract: The frequency dependence of the group delay of both a pulse stretcher and a stretcher–compressor system of a chirped pulse amplification laser is determined with a two-dimensional extension of a spectral interferometric method called the stationary phase point method. The 800-nm, 15-fs probe pulse from a Ti:S oscillator propagates through the stretcher or the stretcher–compressor system. The reference pulse is one of the subsequent oscillator pulses but passes the system and interferes with the probe pulse; hence, a Mach–Zehnder-type interferometer is formed. The shape of the spectrally resolved interference fringes is peculiar to the amount and sign of the relative dispersion properties of the pulses. Group-delay dispersion is obtained from the observation of the position of the stationary phase point in spectrally resolved interferograms at different time delays. This simple method allows for an almost complete and fast alignment of the stretcher–compressor system from scratch until the final adjustments.
TL;DR: In this article, the authors demonstrate the wavefront correction of a 100-TW (25fs, 25J) high repetition rate Ti:sapphire laser using a 36-actuator bimorph deformable mirror.
Patent•
23 Jun 2005TL;DR: In this article, a grating pulse compressor configuration is introduced for increasing the optical dispersion for a given footprint and to make practical the application for chirped pulse amplification (CPA) to quasi-narrow bandwidth materials, such as Nd:YAG.
Abstract: A grating pulse compressor configuration is introduced for increasing the optical dispersion for a given footprint and to make practical the application for chirped pulse amplification (CPA) to quasi-narrow bandwidth materials, such as Nd:YAG. The grating configurations often use cascaded pairs of gratings to increase angular dispersion an order of magnitude or more. Increased angular dispersion allows for decreased grating separation and a smaller compressor footprint.
TL;DR: An experimental study of supercontinuum broadening in photonic crystal fiber performed by measuring the temporal behavior of spectrally-sliced radiation in different propagation regimes confirms the soliton fission theory.
Abstract: We report on an experimental study of supercontinuum broadening in photonic crystal fiber performed by measuring the temporal behavior of spectrally-sliced radiation in different propagation regimes. The study confirms the soliton fission theory by observing the red-shifted fundamental solitons and blue-shifted nonsolitonic radiation.
TL;DR: A new high-contrast, high-gain optical parametric chirped-pulse amplifier (OPCPA) architecture is demonstrated in periodically poled KTiOPO4 (PPKTP), which overcomes parametric fluorescence contrast limitations of the OPCPA in periodicallyPoled materials.
Abstract: A new high-contrast, high-gain optical parametric chirped-pulse amplifier (OPCPA) architecture is demonstrated in periodically poled KTiOPO4 (PPKTP). This architecture overcomes parametric fluorescence contrast limitations of the OPCPA in periodically poled materials. The scheme is based on two passes of a single relay-imaged pump pulse and a free-propagating signal pulse through a 1.5?mm×5?mm×7.5?mm PPKTP crystal. The output energy of 1.2?mJ is generated at a center wavelength of 1053?nm by 24?mJ of pump energy. A prepulse contrast level of >3×107 was measured with >106 saturated gain in the amplifier. Amplified pulses were compressed to 200?fs. This simple and versatile concept requires only a modest pump energy from a commercial pump laser and represents a possible high-contrast front end for high-energy Nd:glass-based petawatt-class lasers.
TL;DR: In this paper, the authors present the current status of the Lucia laser being built at the LULI laboratory, the national civil facility for intense laser matter interaction in France, which will deliver a 100 Joules, 10 ns, 10 Hz pulse train from Yb:YAG using 4400 power diode laser bars.
Abstract: We present the current status of the Lucia laser being built at the LULI laboratory, the national civil facility for intense laser matter interaction in France. This diode pumped laser will deliver a 100 Joules, 10 ns, 10 Hz pulse train from Yb:YAG using 4400 power diode laser bars. We first focus on the amplifier stage by describing the reasons for selecting our extraction architecture. Thermal issues and solutions for both laser and pumping heads are then described. Finally, we emphasize more specifically the need for long-lifetime high-laser-damage-threshold coatings and optics.
TL;DR: In this paper, the residual angular dispersion resulted from the non-parallel surfaces of both a grating pair and a prism pair pulse compressor was investigated. And the corresponding lengthening of the transform limited 18 fs pulses was also determined.
12 Jun 2005
TL;DR: In this paper, a direct pumping scheme using Yb doped fluoride phosphate glass as active material was demonstrated using a stacked laser diode bars at 940 nm wavelength focused tightly to the glass.
Abstract: In this paper, we demonstrate direct pumping scheme using Yb doped fluoride phosphate glass as active material. Antireflective coatings on the glass surface allow using both polarizations for pumping and amplifying as well. The pump system consists of stacked laser diode bars at 940 nm wavelength focused tightly to the glass. Joule-level amplification of broad band width chirped pulses was achieved.
TL;DR: In this paper, angular dispersion of the signal beam inside the non-linear media is added to a common setup to improve the noncollinear phase matching range, and a comparative study of the performance of BBO, LBO and KDP using this geometry is undertaken.
TL;DR: In this paper, the effect of the picking process on the carrier envelope phase stability and the phase noise of the picked pulse sequence can be estimated from the phase-noise properties of the seed oscillator.
Abstract: At present most laser systems for generating phase-stabilized high-energy pulses are chirped pulse amplifier systems that involve the selection and subsequent amplification of pulses from a phase-stabilized seed oscillator. We investigate the effect of the picking process on the carrier envelope phase stability and how the phase noise of the picked pulse sequence can be estimated from the phase noise properties of the seed oscillator. All noise components from the original pulse train above the picking frequency are aliased into the picked pulse train and therefore cannot be neglected.
Patent•
01 Dec 2005TL;DR: In this article, the use of Bragg optical fibers in chirped pulse amplification systems for the production of high-pulse-energy ultrashort optical pulses was discussed.
Abstract: The present invention generally concerns the use of Bragg optical fibers in chirped pulse amplification systems for the production of high-pulse-energy ultrashort optical pulses. A gas-core Bragg optical fiber waveguide (202) can be advantageously used in such systems to stretch the duration of pulses so that they can be amplified, and/or Bragg fibers can be used to compress optical signals into much shorter pulses after they been amplified, Bragg fibers can also function as near-zero-dispersion delay lines in amplifier sections.
08 Nov 2005
TL;DR: In this article, the authors report on the design, fabrication and characterization of multilayer dielectric diffraction gratings for high-energy petawatt laser operation and successfully deliver the first ever 80 cm aperture multi-layer diffraction grating to LLNL's Titan Intense Short Pulse Laser Facility.
Abstract: To enable high-energy petawatt laser operation we have developed the processing methods and tooling that produced both the world's largest multilayer dielectric reflection grating and the world's highest laser damage resistant gratings. We have successfully delivered the first ever 80 cm aperture multilayer dielectric grating to LLNL's Titan Intense Short Pulse Laser Facility. We report on the design, fabrication and characterization of multilayer dielectric diffraction gratings.
05 Oct 2005
TL;DR: In this paper, the design requirements for a thin-film polarizer on the OMEGA EP Laser System include a T p greater than 98% over a spectral range of 1053±4 nm while maintaining a contrast ratio (T p / T s ) of greater than 200:1 (500:1 goal) over the same range.
Abstract: Thin-film polarizers are essential components of large laser systems such as OMEGA EP and the NIF because of the need to switch the beam out of the primary laser cavity (in conjunction with a plasma-electrode Pockels cell) as well as providing a well-defined linear polarization for frequency conversion and protecting the system from back-reflected light. The design and fabrication of polarizers for pulse-compressed laser systems is especially challenging because of the spectral bandwidth necessary for chirped-pulse amplification.
The design requirements for a polarizer on the OMEGA EP Laser System include a T p greater than 98% over a spectral range of 1053±4 nm while maintaining a contrast ratio ( T p / T s ) of greater than 200:1 (500:1 goal) over the same range. An allowance must be made for the uniformity of the film deposition such that the specifications are met over the aperture of the component while allowing for some tolerance of angular misalignment. Production results for hafnia/silica designs will be shown, illustrating high transmission and contrast over an extended wavelength/angular range suitable for the 8 nm spectral bandwidth of OMEGA EP. Difficulties in production will also be illustrated, as well as the methods being implemented to overcome these challenges. A key challenge continues to be the fabrication of such a coating suitable for use on fused-silica substrates in a dry environment. Laser-damage thresholds for 1-ns and 10-ps pulse widths will be discussed.
05 Oct 2005
TL;DR: Shore et al. as discussed by the authors used multilayer dielectric (MLD) gratings as high-damage threshold, high-efficiency diffraction gratings suitable for use in high energy chirped-pulse amplification.
Abstract: The OMEGA EP Facility includes two high-energy, short-pulse laser beams that will be focused to high intensity in the OMEGA target chamber, providing backlighting of compressed fusion targets and investigating the fast-ignition concept. To produce 2.6-kJ output energy per beam, developments in grating compressor technology are required. Gold-coated diffraction gratings limit on-target energy because of their low damage fluence. Multilayer dielectric (MLD) gratings have shown promise as high-damage-threshold, high-efficiency diffraction gratings suitable for use in high-energy chirped-pulse amplification [ B. W. Shore et al., J. Opt. Soc. Am. A 14 , 1124 (1997).] Binary 100-mm-diam MLD gratings have been produced at the Laboratory for Laser Energetics (LLE) using large-aperture, holographic exposure and reactive ion-beam etching systems. A diffraction efficiency of greater than 99.5% at 1053 nm has been achieved for gratings with 1740 grooves/mm, with a 1:1 damage threshold of 5.49 J/cm 2 diffracted beam fluence at 10 ps. To demonstrate the ability to scale up to larger substrates, several 100-mm substrates have been distributed over an aperture of 47 × 43 cm and successfully etched, resulting in high efficiency over the full aperture. This paper details the manufacture and development of these gratings, including the specifics of the MLD coating, holographic lithography, reactive ion etching, reactive ion-beam cleaning, and wet chemical cleaning.
TL;DR: In this article, a combination of negatively and positively chirped pulse amplification (NPCPA) was used to achieve 50 nm spectral width and 150 mJ energy without any additional spectral correction.
Abstract: A laser scheme implementing a combination of negatively and positively chirped pulse amplification (NPCPA) is demonstrated. This method of amplification suppresses spectral narrowing typically appearing in chirped pulse amplification (CPA) lasers thus supporting pulse spectrum much broader than a conventional CPA. With a NPCPA Ti:Sapphire laser we have achieved laser pulses of 50 nm spectral width and 150 mJ energy without any additional spectral correction. The scheme appears as an easy and reliable solution to preserve spectral bandwidth in Ti:Sapphire lasers, especially at high power levels up to the Petawatt regime.