Showing papers on "Chirped pulse amplification published in 2006"
TL;DR: In this paper, a number of consequences of relativistic-strength optical fields are surveyed, including wakefield generation, a relativistically version of optical rectification, in which longitudinal field effects could be as large as the transverse ones.
Abstract: The advent of ultraintense laser pulses generated by the technique of chirped pulse amplification (CPA) along with the development of high-fluence laser materials has opened up an entirely new field of optics. The electromagnetic field intensities produced by these techniques, in excess of ${10}^{18}\phantom{\rule{0.3em}{0ex}}\mathrm{W}∕{\mathrm{cm}}^{2}$, lead to relativistic electron motion in the laser field. The CPA method is reviewed and the future growth of laser technique is discussed, including the prospect of generating the ultimate power of a zettawatt. A number of consequences of relativistic-strength optical fields are surveyed. In contrast to the nonrelativistic regime, these laser fields are capable of moving matter more effectively, including motion in the direction of laser propagation. One of the consequences of this is wakefield generation, a relativistic version of optical rectification, in which longitudinal field effects could be as large as the transverse ones. In addition to this, other effects may occur, including relativistic focusing, relativistic transparency, nonlinear modulation and multiple harmonic generation, and strong coupling to matter and other fields (such as high-frequency radiation). A proper utilization of these phenomena and effects leads to the new technology of relativistic engineering, in which light-matter interactions in the relativistic regime drives the development of laser-driven accelerator science. A number of significant applications are reviewed, including the fast ignition of an inertially confined fusion target by short-pulsed laser energy and potential sources of energetic particles (electrons, protons, other ions, positrons, pions, etc.). The coupling of an intense laser field to matter also has implications for the study of the highest energies in astrophysics, such as ultrahigh-energy cosmic rays, with energies in excess of ${10}^{20}\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$. The laser fields can be so intense as to make the accelerating field large enough for general relativistic effects (via the equivalence principle) to be examined in the laboratory. It will also enable one to access the nonlinear regime of quantum electrodynamics, where the effects of radiative damping are no longer negligible. Furthermore, when the fields are close to the Schwinger value, the vacuum can behave like a nonlinear medium in much the same way as ordinary dielectric matter expanded to laser radiation in the early days of laser research.
1,459 citations
TL;DR: In this article, the authors discuss the main issues of optical parametric chirped pulse amplification and overview recent progress in the field and discuss a broad class of femtosecond laser systems with output power ranging from a few gigawatts to hundreds of terawatts, with the potential of generating few-optical-cycle pulses at the petawatt power level.
Abstract: Since the proof-of-principle demonstration of optical parametric amplifier to efficiently amplify chirped pulses in 1992, optical parametric chirped pulse amplification (OPCPA) became a widely recognized and rapidly developing technique for high-power femtosecond pulse generation. In the meantime, we are witnessing an exciting progress in the development of powerful and ultrashort pulse laser systems that employ chirped pulse parametric amplifiers. These systems cover a broad class of femtosecond lasers, with output power ranging from a few gigawatts to hundreds of terawatts, with a potential of generating few-optical-cycle pulses at the petawatt power level. In this paper, we discuss the main issues of optical parametric chirped pulse amplification and overview recent progress in the field.
218 citations
TL;DR: In this paper, the challenges, achievements, and perspectives of ultrashort pulse generation and amplification in fibers are reviewed, as well as novel experimental strategies and fiber designs offer an enormous potential toward laser systems with high average powers and high pulse energies.
Abstract: The recent demonstration of rare-earth-doped fiber lasers with a continuous wave output power well above the kilowatt level with diffraction-limited beam quality has proven that fiber lasers constitute a power-scalable solid-state laser concept. To generate intense pulses from a fiber, several fundamental limitations have to be overcome. Nevertheless, novel experimental strategies and fiber designs offer an enormous potential toward laser systems with high average powers and high pulse energies. This paper reviews the challenges, achievements, and perspectives of ultrashort pulse generation and amplification in fibers.
196 citations
TL;DR: A noncollinear optical parametric chirped pulse amplifier system that produces 7.6 fs pulses with a peak power of 2 terawatt at 30 Hz repetition rate is demonstrated.
Abstract: We demonstrate a noncollinear optical parametric chirped pulse amplifier system that produces 7.6 fs pulses with a peak power of 2 terawatt at 30 Hz repetition rate. Using an ultra-broadband Ti:Sapphire seed oscillator and grating-based stretching and compression combined with an LCD phase-shaper, we amplify a 310 nm wide spectrum with a total gain of 3×107, and compress it within 5% of its Fourier limit. The total integrated parametric fluorescence is kept below 0.2%, leading to a pre-pulse contrast of 2×10-8 on picosecond timescales.
170 citations
TL;DR: The amplification of broadband pulses from a Ti:Sapphire oscillator by non-collinear optical parametric chirped-pulse amplification technique in a type-I BBO crystal to energies of 90 mJ is demonstrated.
Abstract: We demonstrate the amplification of broadband pulses from a Ti:Sapphire oscillator by non-collinear optical parametric chirped-pulse amplification technique in a type-I BBO crystal to energies of 90 mJ. Partial compression of the amplified pulses is demonstrated down to a 10 fs duration. These parameters come in combination with good spatial quality and focusability of the amplified beam.
134 citations
TL;DR: What is believed to be the first large-aperture and high-energy optical parametric chirped pulse amplification system, based on a three-stage amplifier, shows 25% pump-to-signal conversion efficiency and amplification of the full 70 nm width of the seed spectrum.
Abstract: We report on what is believed to be the first large-aperture and high-energy optical parametric chirped pulse amplification system. The system, based on a three-stage amplifier, shows 25% pump-to-signal conversion efficiency and amplification of the full 70 nm width of the seed spectrum. Pulse compression to 84 fs achieved after amplification indicates a potential of 300 TW pulse power for 35 J amplified pulse energy.
120 citations
TL;DR: In this paper, a Cr:forsterite master oscillator at 1250 nm, a stretcher, three optical parametrical amplifiers based on KD*P (DKDP) crystals providing 14.5 J energy in the chirped pulse at 910 nm central wavelength, and a vacuum compressor were described in detail.
Abstract: 200 TW peak power has been achieved experimentally using a Cr:forsterite master oscillator at 1250 nm, a stretcher, three optical parametrical amplifiers based on KD*P (DKDP) crystals providing 14.5 J energy in the chirped pulse at 910 nm central wavelength, and a vacuum compressor. The final parametrical amplifier and the compressor are described in detail. Scaling of such architecture to multipetawatt power is discussed.
111 citations
Patent•
19 Jul 2006TL;DR: A chirped pulse amplification system includes one or more polarization compensators configured to compensate for polarization altering elements with the Chirped Pulse Amplification System (CPAS) as discussed by the authors.
Abstract: A chirped pulse amplification system includes one or more polarization compensator configured to compensate for polarization altering elements with the chirped pulse amplification system. The polarization compensator is responsive to a sensor configured to provide feedback to the polarization compensator. In some embodiments, the chirped pulse amplification system further includes a controller configured to automatically adjust the polarization compensator responsive to the sensor. The sensor is optionally a power sensor.
110 citations
TL;DR: A 50 W sub-picosecond fiber chirped pulse amplification system generating 50 muJ pulses at a repetition rate of 1 MHz is demonstrated, required for precision high speed micro-machining.
Abstract: A 50 W sub-picosecond fiber chirped pulse amplification system generating 50 µJ pulses at a repetition rate of 1 MHz is demonstrated. As required for precision high speed micro-machining, this system has a practical system configuration enabled by the fiber stretcher and 1780 l/mm dielectric diffraction grating compressor and is capable of ablation rates >0.17 mm3/s metal, ceramic, and glass.
81 citations
TL;DR: Large crystals of yttrium calcium oxyborate have been grown and utilized for high-average-power second-harmonic generation and what is believed to be the first use of YCOB for OPCPA, where Scalability to higher peak and average power is addressed.
Abstract: Optical parametric chirped-pulse amplification (OPCPA) in nonlinear crystals has the potential to produce extremes of peak and average power but is limited either in energy by crystal growth issues or in average power by crystal thermo-optic characteristics. Recently, large (7.5 cm diameter × 25 cm length) crystals of yttrium calcium oxyborate (YCOB) have been grown and utilized for high-average-power second-harmonic generation. Further, YCOB has the necessary thermo-optic properties required for scaling OPCPA systems to high peak and average power operation for wavelengths near 1 μm. We report what is believed to be the first use of YCOB for OPCPA. Scalability to higher peak and average power is addressed.
62 citations
TL;DR: It is demonstrated that the carrier-envelope (CE) phase of pulses from a high power ultrafast laser system with a grating-based stretcher and compressor can be stabilized to a root mean square (rms) value of 180 mrad over almost 2 hours, excluding a brief re-locking period.
Abstract: It is demonstrated that the carrier-envelope (CE) phase of pulses from a high power ultrafast laser system with a grating-based stretcher and compressor can be stabilized to a root mean square (rms) value of 180 mrad over almost 2 hours, excluding a brief re-locking period. The stabilization was accomplished via feedback control of the stretcher grating separation in the stretcher. It shows that the long term CE phase stability of a grating based chirped pulse amplification system can be as good as that of lasers using a glass-block stretcher and a prism pair compressor. Moreover, by adjusting the grating separation to preset values, the relative CE phase could be locked to an arbitrary value in the range of 2π. This method is better than using a pair of wedge plates to adjust the phase after a hollow-core fiber compressor. The CE phase stabilization after a hollow-core fiber compressor was confirmed by a CE-phase meter based on the measurement of the left-to-right asymmetry of electrons produced by above-threshold ionization.
TL;DR: In this article, a new Brewster cut acousto-optic programmable gain control filter was developed to optimize the spectral losses inside a regenerative cavity, which combined with a programmable dispersive filter for the spectral phase control optimizes, in a few steps of a direct algorithm, the performance of a 10Hz CPA Ti:sapphire laser to 18-fs pulse duration, 1.2% RMS energy stability and 107 contrast ratio.
Abstract: We have developed a new Brewster-cut acousto-optic programmable gain control filter to optimize the spectral losses inside a regenerative cavity. This spectral amplitude control combined with an acousto-optic programmable dispersive filter for the spectral phase control optimizes, in a few steps of a direct algorithm, the performance of a 10-Hz CPA Ti:sapphire laser to 18-fs pulse duration, 1.2% RMS energy stability and 107 contrast ratio.
TL;DR: In this article, the authors study parametric amplification in optical fibers for chirped-pulse femtosecond laser systems and provide a proof of principle for a picosecond 1064 nm pump and femto-cond 1025 nm signal.
Abstract: We study parametric amplification in optical fibers for chirped-pulse femtosecond laser systems. Compared to conventional OPCPA operating in bulk crystals, the fiber geometry offers a greater interaction length and spatial confinement, an increased flexibility in the choice of wavelengths for signal and pump beams, and the robustness of fiber setups. As opposed to rare-earth doped fibers, parametric amplifiers potentially provide wideband amplification in arbitrary regions of the spectrum. Numerical simulations are undertaken as a proof of principle for a picosecond 1064 nm pump and femtosecond 1025 nm signal. Guidelines for phase matching engineering are given, and limitations in spectral bandwidth and achievable pulse energy are discussed.
TL;DR: In this article, the authors demonstrate the technique of cross-polarized wave (XPW) generation at 1 μm with a 310-fs optical parametric chirped-pulse amplification system at the millijoule level.
Abstract: We demonstrate the technique of cross-polarized wave (XPW) generation at 1 μm with a 310-fs optical parametric chirped-pulse amplification system at the millijoule level. We show an improvement of the temporal contrast by three orders of magnitude with an energy transmission of 22%. Additionally, we report that XPW generation preserves the beam spatial quality and shortens the pulse duration by a factor of 31/2, resulting in a peak power transmission of ∼35%.
TL;DR: In this paper, the effects of self-focusing and multi-photon ionization during the beam propagation were minimized by differentially pumping the hollow fiber filled with neon, and the spectral broadening at the hollow-fiber compressor was optimized by adjusting gas pressure, laser intensity, and laser chirp.
Abstract: Optical pulses with 1.1-mJ energy and 5.5-fs duration have been generated at 1-kHz repetition rate from a chirped pulse amplification Ti:Sapphire laser incorporating a differentially pumped hollow-fiber chirped-mirror compressor. The effects of self-focusing and multi-photon ionization during the beam propagation were minimized by differentially pumping the hollow fiber filled with neon. The spectral broadening at the hollow-fiber compressor was optimized by adjusting gas pressure, laser intensity, and laser chirp, covering from 540 nm to 950 nm.
TL;DR: The 100 fs pulses of an erbium fiber laser are parametrically amplified while synchronously pumped by an amplified mode-locked Nd:YLF laser with saturated gain of 65 dB with 30% conversion efficiency and has produced 160 fs pulses with peak powers of up to 0.75 GW.
Abstract: Amplification of femtosecond pulses at 1.56 μm based on noncollinear parametric chirped pulse amplification in a potassium titanyl arsenate (KTA) crystal with pumping at 1.05 μm is reported. The 100 fs pulses of an erbium fiber laser are parametrically amplified while synchronously pumped by an amplified mode-locked Nd:YLF laser. This amplifier has a saturated gain of 65 dB with 30% conversion efficiency and has produced 160 fs pulses with peak powers of up to 0.75 GW. The system produced 380 mW before compression and can be readily scaled to the multiwatt range with bandwidths to support sub-100 fs pulses.
TL;DR: A high-energy petawatt laser, OMEGA EP, is currently under construction at the University of Rochester's Laboratory for Laser Energetics (LLE).
Abstract: A high-energy petawatt laser, OMEGA EP, is currently under construction at the University of Rochester's Laboratory for Laser Energetics. Integrated into the existing OMEGA laser, it will support three major areas of research: (a) backlighting of high-energy-density plasmas, (b) integrated fast ignition experiments, and (c) high-intensity physics. The laser will provide two beams combined collinearly and coaxially with short pulses (~1 to 100 ps) and high energy (2.6 kJ at 10 ps). Cone-in-shell fuel-assembly experiments and simulations of short-pulse heated cryogenic targets are being performed in preparation for cryogenic integrated fast ignitor experiments on OMEGA EP.
TL;DR: In this paper, the amplified optical parametric fluorescence (AOPF) from OPCPA was controlled by injecting a residual fundamental pulse of the seeded Q-switch Nd:YAG pumping laser as a quenching beam.
Abstract: The amplified optical parametric fluorescence (AOPF) from optical parametric chirped pulse amplifier (OPCPA) was controlled by injecting a residual fundamental pulse of the seeded Q-switch Nd:YAG pumping laser as a quenching beam. The output pulse from the OPCPA was used as a seed pulse for Ti:sapphire chirped-pulse amplifier (CPA) system to generate up to 10 TW peak power with a high-contrast ratio. This intense laser pulse was focused on the supersonic Ar gas jet. High-energy electrons up to 30 MeV were observed.
TL;DR: In this paper, the authors demonstrate a simple, all-fiber technique for removing nonlinear phase due to self-phase modulation in fiber-based chirped-pulse amplification (CPA) systems.
Abstract: We demonstrate a simple, all-fiber technique for removing nonlinear phase due to self-phase modulation in fiber-based chirped-pulse amplification (CPA) systems. Using a LiNbO3 electro-optic phase modulator to emulate a negative nonlinear index of refraction, we are able to remove 1.0 π rad of self-phase modulation acquired by pulses during amplification and eliminate nearly all pulse distortion. Our technique is high speed, removes nonlinear phase on a pulse-to-pulse basis, and can be readily integrated into existing CPA systems.
DSM1
TL;DR: In this article, the effects of the light reaching the medium before the pulse were investigated and it was shown that such effects are basically of refractive nature and that they are not detrimental for the propagation of a CPA pulse focused to moderately relativistic intensity.
Abstract: The propagation of an ultrashort laser pulse can be affected by the light reaching the medium before the pulse. This can cause a serious drawback to possible applications. The propagation in He of an intense 60-fs pulse delivered by a Ti:sapphire laser in the chirped pulse amplification (CPA) mode has been investigated in conditions of interest for laser-plasma acceleration of electrons. The effects of both nanosecond amplified spontaneous emission and picosecond pedestals have been clearly identified. There is evidence that such effects are basically of refractive nature and that they are not detrimental for the propagation of a CPA pulse focused to moderately relativistic intensity. The observations are fully consistent with numerical simulations and can contribute to the search of a stable regime for laser acceleration.
Patent•
28 Mar 2006TL;DR: In this paper, a chirped pulse amplification (CPA) system and method is described wherein the dispersion of the system is tuned by actively tuning one or more system components, for example, using a temperature or strain gradient, or using actinic radiation.
Abstract: A chirped pulse amplification (CPA) system and method is described wherein the dispersion of the system is tuned by actively tuning one or more system components, for example, using a temperature or strain gradient, or using actinic radiation. In other embodiments, an additional element, such as a modulator, is added to the CPA system to actively to tune the pulse. A pulse monitor is added to the system to measure an output pulse and provide feedback to one or more active tuning elements.
TL;DR: In this article, the authors present an overview of the current capabilities of the Vulcan Petawatt facility and discuss some of the recent technological advances that have enabled the generation of petawatt pulses.
Abstract: Petawatt capability on the Vulcan laser facility has been available to the international plasma physics community for over two years. This has enabled novel experiments to be carried out and new regimes of physics to be explored. During that time, there have been 10 successful user experiments with 89% of shots delivered within the requested energy limits. In the autumn of 2004, pulses with powers of more than a petawatt (10 15 Watts) were delivered to target with energies greater than 400 J and pulse widths shorter than 500 femtoseconds (10 -15 ) on target. In parallel to the development of ultra-high intensity pulses is a programme to enhance Vulcan's long pulse capabilities. This paper will present an overview of the current capabilities of the Vulcan Petawatt facility and discuss some of the recent technological advances that have enabled the generation of Petawatt pulses.
04 Apr 2006
TL;DR: In this paper, a new amplifying laser concept based on Coherent Amplification Network (CAN) is proposed to solve the high-peak high-average-power quandary.
Abstract: A new amplifying laser concept based on Coherent Amplification Network (CAN) is proposed to solve the high‐peak high‐average‐power quandary. The amplification network is based on identical telecommunication diode‐pumped fiber lasers. The philosophy behind the approach is to build the amplifying system from numerous small but identical parts as opposed to larger but non‐identical components like in the laser Megajoule in France or NIF in the USA. The basic amplification scheme is in‐fiber Chirped Pulse Amplification. Besides the possibility to simultaneously provide high peak and high average power, the technique gives independent control of the output beam spatial and temporal coherence, as well as the pupilary distribution. In addition to being rugged, CAN offers the additional benefit of being inexpensive and low maintenance. A conceptual design based on CAN is presented that offers an alternative to the next CERN Linear Collider (CLIC).
TL;DR: In this paper, the authors developed an innovative high contrast multiterawatt femtosecond laser chain based on a hybrid (solid/gas) technology, which includes a Ti:sapphire oscillator generating 50 fs pulses at 950 nm, an optical parametric chirped pulse amplification stage, a second harmonic frequency converter for pulse temporal cleaning, and a final photolytical XeF(C-A) excimer amplifier for direct high peak-power amplification of ultrashort laser pulses in the blue (475 nm) spectral region.
Abstract: The strategy used to develop an innovative high contrast multiterawatt femtosecond laser chain based on a hybrid (solid/gas) technology is reported. The laser system includes a Ti:sapphire oscillator generating 50 fs pulses at 950 nm, an optical parametric chirped pulse amplification stage, a second harmonic frequency converter for pulse temporal cleaning, and a final photolytical XeF(C–A) excimer amplifier for direct high peak-power amplification of ultrashort laser pulses in the blue (475 nm) spectral region. Several important issues concerning the design of the laser front-end, the energy extraction and beam phase control in the high peak-power XeF(C–A) amplifier are theoretically addressed. A detailed description of the XeF(C–A) amplifier and careful measurements of its energetic, optical and pumping characteristics are also given, together with the first pilot amplification experiments in the low density XeF(C–A) medium to assert the significance of our approach.
TL;DR: A prepulse-free, multi-terawatt, ultrashort pulse laser system, which combines both conventional laser amplification and optical parametric chirped pulse amplification (OPCPA) techniques, and dramatically enhanced the prepulse contrast by 6 orders of magnitude.
Abstract: We have built a prepulse-free, multi-terawatt, ultrashort pulse laser system, which combines both conventional laser amplification and optical parametric chirped pulse amplification (OPCPA) techniques. By employing an OPCPA system after the regenerative amplifier in a Ti:sapphire chirped pulse amplification laser chain, we have dramatically enhanced the prepulse contrast by 6 orders of magnitude. A prepulse contrast of better than 4.4 × 10-11 has been measured with a high energy broadband pulse of 24 mJ at 10 Hz repetition rate from the OPCPA system. Using a subsequent four-pass Ti:sapphire amplifier, we have achieved an amplified energy of 279 mJ and an ultrashort recompressed amplified pulse duration of 23.5 fs, corresponding to the peak powers for OPCPA and four-pass amplifier of 0.5 TW and 5.9 TW, respectively.
Patent•
22 Dec 2006TL;DR: In this paper, a chirped pulse amplification (CPA) method is described, where the pulse is either stretched using multiple passes through a Bragg grating or compressed by using multiple pass through a grating.
Abstract: A chirped pulse amplification (CPA) system and method is described wherein the pulse is stretched using multiple passes through a Bragg grating or compressed using multiple passes through a Bragg grating. A switch may be used to control the number of passes through the Bragg grating, thus, tuning the compressed or the stretched pulse width. The pulse may be directed through an amplifier between the multiple passes through the Bragg grating to apply amplification to the stretched pulse multiple times. The Bragg grating may include a fiber Bragg grating, a volume Bragg grating, or a Bragg waveguide.
TL;DR: In this paper, a third-order correlator suitable for detailed shape measurements of picosecond laser pulses has been developed, based on the phase-matched difference frequency non-collinear generated signal in a nonlinear crystal.
26 May 2006
TL;DR: In this paper, a phase element was used to control the far-field intensity pattern generated by a high-peak-power, femtosecond laser, which results in a well defined location of the filaments formed by the propagation of these beams through the atmosphere.
Abstract: We report on the use of a novel phase element to control the far-field intensity pattern generated by a high-peak-power, femtosecond laser. The pre-determined intensity pattern results in a well defined location of the filaments formed by the propagation of these beams through the atmosphere. This enhancement of the localization and repeatability of the intensity distribution can be extremely beneficial for laser induced breakdown spectroscopy (LIBS) of remote regions of interest.
Patent•
24 May 2006TL;DR: In this paper, the use of Bragg optical fibers in chirped pulse amplification systems for the production of high-pulse-energy ultrashort optical pulses was discussed, where a gas-core Bragg fiber waveguide was used 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 duration pulses after they have been amplified.
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 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 duration pulses after they have been amplified. Bragg fibers can also function as near-zero-dispersion delay lines in amplifier sections.
TL;DR: In this paper, a TW-class 12-fs Ti:sapphire chirped-pulse amplification system was described and a construction of a TW class 12-fps 12-mm pulse stretcher, a broadband gain-narrowing compensator, broadband high energy mirrors, high energy dichroic mirrors, a dispersion compensator and a broadband pulse compressor for /spl sim/10-fs pulse generation.
Abstract: We describe a design and a construction of a TW-class 12-fs Ti:sapphire chirped-pulse amplification system. We developed a broadband pulse stretcher, a broadband gain-narrowing compensator, broadband high-energy mirrors, high-energy dichroic chirped mirrors, a dispersion compensator, and a broadband pulse compressor for /spl sim/10-fs pulse generation. Utilizing these optical devices, we demonstrated a generation of 12-fs pulses from a 10-Hz-repetition-rate Ti:sapphire chirped-pulse multipass amplifier system and a 1-kHz-repetition-rate Ti:sapphire chirped-pulse regenerative amplifier system. Optimized designs of broadband Ti:sapphire amplifiers with multilayer gain-narrowing compensators and an adaptive dispersion compensator with a spatial light modulator contribute to the shorter pulse amplification.