Showing papers on "Chirped pulse amplification published in 2008"
TL;DR: This work demonstrates a method of high-harmonic generation that requires no extra cavities by exploiting the local field enhancement induced by resonant plasmons within a metallic nanostructure consisting of bow-tie-shaped gold elements on a sapphire substrate.
Abstract: High-harmonic generation by focusing a femtosecond laser onto a gas is a well-known method of producing coherent extreme-ultraviolet (EUV) light. This nonlinear conversion process requires high pulse intensities, greater than 10(13) W cm(-2), which are not directly attainable using only the output power of a femtosecond oscillator. Chirped-pulse amplification enables the pulse intensity to exceed this threshold by incorporating several regenerative and/or multi-pass amplifier cavities in tandem. Intracavity pulse amplification (designed not to reduce the pulse repetition rate) also requires a long cavity. Here we demonstrate a method of high-harmonic generation that requires no extra cavities. This is achieved by exploiting the local field enhancement induced by resonant plasmons within a metallic nanostructure consisting of bow-tie-shaped gold elements on a sapphire substrate. In our experiment, the output beam emitted from a modest femtosecond oscillator (100-kW peak power, 1.3-nJ pulse energy and 10-fs pulse duration) is directly focused onto the nanostructure with a pulse intensity of only 10(11) W cm(-2). The enhancement factor exceeds 20 dB, which is sufficient to produce EUV wavelengths down to 47 nm by injection with an argon gas jet. The method could form the basis for constructing laptop-sized EUV light sources for advanced lithography and high-resolution imaging applications.
1,320 citations
TL;DR: What is believed to be the first terawatt diode-pumped laser employing single-crystalline Yb:CaF(2) as the amplifying medium was presented, and nanosecond pulses containing an energy of up to 905 mJ were generated without optical damage.
Abstract: We present what we believe to be the first terawatt diode-pumped laser employing single-crystalline Yb:CaF2 as the amplifying medium. A maximum pulse energy of 420 mJ at a repetition rate of 1 Hz was achieved by seeding with a stretched femtosecond pulse 2 ns in duration, preamplified to 40 mJ. After recompression, a pulse energy of 197 mJ and a duration of 192 fs were obtained, corresponding to a peak power of 1 TW. Furthermore, nanosecond pulses containing an energy of up to 905 mJ were generated without optical damage.
127 citations
TL;DR: This system is, to the authors' knowledge, the first 100 TW class laser to combine simultaneously ultra high intensity, 10(9) laser pulse contrast ratio and 10 Hz high repetition rate.
Abstract: We successfully implemented laser beam wavefront correction on the 200 TW laser system at the Advanced Laser Light Source. Ultra high intensities in excess of 10(20) W/cm(2) have been demonstrated. This system is, to our knowledge, the first 100 TW class laser to combine simultaneously ultra high intensity, 10(9) laser pulse contrast ratio and 10 Hz high repetition rate.
75 citations
TL;DR: This amplification system is well suited for pumping high-power high-repetition-rate optical parametric chirped-pulse amplifiers and supports power scalability to a > 10 kW level without being affected by self-phase modulation.
Abstract: We generate linearly polarized, 287 W average-power, 5.5 ps pulses using a cryogenically cooled Yb:YAG amplifier at a repetition rate of 78 MHz. An optical-to-optical efficiency of 41% is obtained at 700 W pump power. A 6 W, 0.4 nm bandwidth picosecond seed source at 1029 nm wavelength is constructed using a chirped-pulse fiber amplification chain based on chirped volume Bragg gratings. The combination of a fiber amplifier system and a cryogenically cooled Yb:YAG amplifier results in good spatial beam quality at large average power. Low nonlinear phase accumulation as small as 5.1×10−3 rad in the bulk Yb:YAG amplifier supports power scalability to a >10 kW level without being affected by self-phase modulation. This amplification system is well suited for pumping high-power high-repetition-rate optical parametric chirped-pulse amplifiers.
71 citations
TL;DR: A high-contrast, high-intensity Ti:sapphire chirped-pulses amplification system that incorporates a nonlinear preamplifier based on optical parametric chirping-pulse amplification (OPCPA) that significantly improves the temporal contrast to better than 7x10(-9) in a few picoseconds interval prior to the main laser pulse.
Abstract: We report a high-contrast, high-intensity Ti:sapphire chirped-pulse amplification system that incorporates a nonlinear preamplifier based on optical parametric chirped-pulse amplification (OPCPA). By cooling the Ti:sapphire crystal in the final amplifier down to 77 K, the chirped-pulses are amplified to 2.9 J at a 10 Hz repetition rate without a thermal lensing effect. Pulse compression down to 19 fs duration obtained after amplification indicates a peak power of 80 TW. With the OPCPA, the temporal contrast is significantly improved to better than 7x10(-9) in a few picoseconds interval prior to the main laser pulse.
64 citations
TL;DR: In this paper, a high average power fiber chirped pulse amplification (FCPA) system with a microstructured large-mode-area fiber for nonlinear compression is presented.
Abstract: We report on the generation of 27 fs pulses with an average output power of 57 W and a repetition rate of 78 MHz. The pulses are generated by combining a high average power fiber chirped pulse amplification (FCPA) system with a microstructured large-mode-area fiber for nonlinear compression. The FCPA system delivers 270 fs pulses in a linearly polarized beam with diffraction-limited quality. Nonlinear compression is achieved by launching the pulses into a short (few cm) piece of microstructured fiber and subsequent compression by a pair of chirped mirrors.
60 citations
TL;DR: Fiber-Chirped Pulse Amplification (FCPA) as mentioned in this paper is bridging these two performance regimes, producing relatively high pulse energies (compared to oscillators) and relatively high repetition rates in a robust and reliable package.
Abstract: Industrial micromachining applications with ultrashort pulse lasers are often difficult to make practical due to the lack of robustness of the laser and the slow processing speed resulting from the low repetition rate. In the past, amplified, femtosecond lasers produced high pulse energies, but at a slow pulse repetition rate of around a kHz. The high repetition rate oscillators did not have enough pulse energy for micromachining of most industrial materials. Fiber Chirped Pulse Amplification (FCPA) is bridging these two performance regimes, produc-ing relatively high pulse energies (compared to oscillators) and relatively high repetition rates (compared to amplifiers) in a robust and reliable package. The FCPA
56 citations
TL;DR: A detrimental pulse distortion mechanism inherent to nonlinear chirped-pulse amplification systems is revealed and analyzed and applications relying on a high pulse-contrast demand a low B-integral of the amplification system and a master-oscillator that exhibits an excellent pulse- Contrast.
Abstract: A detrimental pulse distortion mechanism inherent to nonlinear chirped-pulse amplification systems is revealed and analyzed. When seeding the nonlinear amplification stage with pulses possessing weak side-pulses, the Kerr-nonlinearity causes a transfer of energy from the main pulse to side pulses. The resulting decrease in pulse contrast is determined by the accumulated nonlinear phase-shift (i.e., the B-integral) and the initial pulse-contrast. The energy transfer can be described by Bessel-functions. Thus, applications relying on a high pulse-contrast demand a low B-integral of the amplification system and a master-oscillator that exhibits an excellent pulse-contrast. In particular, nonlinear fiber CPA-systems operated at B-integrals far beyond pi have to be revised in this context.
54 citations
TL;DR: A short-p pulse source based on optical parametric chirped-pulse amplification (OPCPA) technology has been developed with properties that make it a suitable seed for a high-energy OPCPA system.
Abstract: A short-pulse source based on optical parametric chirped-pulse amplification (OPCPA) technology has been developed with properties that make it a suitable seed for a high-energy OPCPA system. This source generated a diffraction-limited pulse at 910 nm with a full bandwidth of > 165 nm and a spectrum having a transform-limited pulse duration of less than 15 fs. The technique has potential for generating bandwidths > 200 nm and pulse durations < 10 fs.
51 citations
TL;DR: A multi-Petawatt high-energy laser PETAL coupled to the Ligne d'Int?gration Laser (LIL) is under construction in the Aquitaine Region in France.
Abstract: A multi-Petawatt high-energy laser PETAL coupled to the Ligne d'Int?gration Laser (LIL) is under construction in the Aquitaine Region in France. This Petawatt laser will be dedicated to academic experiments in the fields of high energy density physics and ultra high intensity. Nd?:?glass laser chain coupled with the chirped pulse amplification (CPA technique allows delivery of high energy. Optical parametric CPA for pre-amplification and a new compression scheme will be implemented. PETAL is designed to deliver 3.6?kJ of energy in 500?fs on a target corresponding to 7.2?PW. The PETAL beam linked to the up to 60?kJ?ns UV beams from the LIL will present new scientific research opportunities.
51 citations
TL;DR: Two large-aperture tiled-grating compressors have been built for the OMEGA EP high-energy petawatt-class laser system and both compressors achieved subpicosecond pulse duration without tiling-induced temporal degradation.
Abstract: Two large-aperture tiled-grating (1.5 m) compressors, each consisting of four sets of tiled-grating assemblies, have been built for the OMEGA EP high-energy petawatt-class laser system. The techniques used for tiling individual tiled-grating assemblies and for optimizing the overall performance of a tiled-grating compressor are described. Both compressors achieved subpicosecond pulse duration without tiling-induced temporal degradation. A ray-tracing model predicted that the static wavefront of the grating tiles dominated focal-spot degradations when submicroradian tiling accuracy is achieved. The tiled-grating compressors delivered a tighter focal spot compared with subaperture grating compressors with single central tiles.
TL;DR: The obtained results show that cavity-assisted non-collinear high harmonic generation is a promising candidate for efficient generation and outcoupling of extreme ultraviolet (XUV) radiation.
Abstract: We present first experimental results of our investigation of non-collinear high harmonic generation (NCHHG) with a chirped pulse amplification system. Collimated high harmonic radiation of higher than 9th order is observed along the bisector of two fundamental beams crossing in a xenon gas target. The obtained results show that cavity-assisted non-collinear high harmonic generation is a promising candidate for efficient generation and outcoupling of extreme ultraviolet (XUV) radiation.
TL;DR: In this paper, the authors introduce a criterion classifying laser materials with respect to their ability to generate pulses of highest peak power in a diode-pumped solid state laser system.
Abstract: The generation of the highest laser peak intensities at a high degree of system compactness can be achieved by combining modern diode-pump technologies with the chirped pulse amplification technique. In principle, the spectroscopic properties of the gain medium determine the scaling laws of both high output pulse energy and short pulse duration. Here we introduce a novel criterion classifying laser materials with respect to their ability to generate pulses of highest peak power in a diode-pumped solid state laser system. Furthermore, amplified spontaneous emission as well as laser damage issues affecting the efficiency and compactness of a laser amplifier system are discussed.
TL;DR: It is analytically shown that weak initial spectral phase modulations cause a pulse-contrast degradation at the output of nonlinear chirped-pulse amplification systems, and the intensities of the pulses are dependent on the magnitude of the accumulated nonlinear phase-shift.
Abstract: It is analytically shown that weak initial spectral phase modulations cause a pulse-contrast degradation at the output of nonlinear chirped-pulse amplification systems The Kerr-nonlinearity causes an energy-transfer from the main pulse to side-pulses during nonlinear amplification The relative intensities of these side-pulses can be described in terms of Bessel-functions It is shown that the intensities of the pulses are dependent on the magnitude of the accumulated nonlinear phase-shift (ie, the B-integral), the depth and period of the initial spectral phase-modulation and the slope of the linear stretching chirp The results are applicable to any type of laser amplifier that is based on the technique of chirped-pulse amplification The analytical results presented in this paper are of particular importance for high peak-power laser applications requiring high pulse-contrasts, eg high field physics
TL;DR: In this article, a femtosecond infrared laser source based on a three-stage chirped-pulse amplification scheme is presented, which can be used to perform second-order nonlinear optical surface spectroscopy in the fingerprint region.
Abstract: We present a novel high power femtosecond infrared laser source, based on a three-stage chirped-pulse amplification scheme. Owing to the high power output of the Ti:sapphire amplifiers, it becomes routinely possible to produce femtosecond infrared laser pulses in the wavelength region of 2.6–20 μm with minimum pulse energies of 15 μJ, to our knowledge roughly an improvement of an order of magnitude. With such pulses we have performed femtosecond second-order nonlinear optical surface spectroscopy in the fingerprint region. We have probed the skeletal modes of the first few monolayers of a polymer/air interface in a femtosecond vibrational sum frequency generation experiment. This development opens up new possibilities to investigate surface structures and dynamics of, e.g., organo-metallic compounds, proteins, and peptides.
TL;DR: In this article, a 1kJ PW laser system based on its Nd:glass ninth beam has been designed for the scientific research on high energy density physics, ICF, especially the fast ignition.
Abstract: With the upgrade program of SG-II laser facility, 1kJ PW laser system based on its Nd:glass ninth beam has been designed for the scientific research on high energy density physics, ICF, especially the fast ignition. In this paper the design overview is presented. According to the schedule, the installation of optics and mechanics will be finished by the middle of 2009, and the operation will start in half year later.
TL;DR: In this paper, the role of spectral phase on cross-polarized wave (XPW) generation using sub-30 femtosecond (fs) laser pulses is investigated.
Abstract: In this paper we present the first comprehensive study of the role of spectral phase on cross-polarized wave (XPW) generation using sub-30 femtosecond (fs) laser pulses. XPW generation improves the temporal contrast and shortens the pulse duration of fs chirped pulse amplification (CPA) lasers. For Ti:Sa lasers, compression below 30 fs is non-trivial and therefore never perfect. We therefore systematically analyze the effect of an arbitrary input spectral phase on the output spectrum and efficiency of the XPW process, both theoretically and experimentally. We derive the maximum acceptable value of residual phase for a given initial pulse duration in order to efficiently drive the XPW process for pulse shortening and contrast improvement.
04 May 2008
TL;DR: It is demonstrated threefold increased autocorrelation peak from an Yb-fiber CPA system operating with strong self-phase modulation by pre-shaping the pulse spectral-phase by adapting the adaptive control loop using feedback from the output autOCorrelation.
Abstract: We demonstrate threefold increased autocorrelation peak from an Yb-fiber CPA system operating with strong self-phase modulation by pre-shaping the pulse spectral-phase. The adaptive control loop used feedback from the output autocorrelation. High-quality 800 fs, 65 muJ recompressed pulses were produced.
TL;DR: This is the first demonstration, to the best of the knowledge, of the direct amplification of terawatt sub-10-fs pulses in a chirped pulse amplification system of Ti:sapphire laser.
Abstract: We have developed a chirped pulse amplification system of Ti:sapphire laser generating a 9.9 fs pulse with a pulse energy of 11 mJ at a repetition rate of 10 Hz. Spectral narrowing during amplification is successfully compensated by using specially designed partial mirrors and broadband high-damage-threshold mirrors. This is the first demonstration, to the best of our knowledge, of the direct amplification of terawatt sub-10-fs pulses in a chirped pulse amplification system of Ti:sapphire laser.
TL;DR: A parametric amplifier pumped by the frequency doubled output of a state-of-the-art fiber chirped pulse amplification system (FCPA) delivering mJ pulse energy at 30 kHz repetition rate and 650 fs pulse duration and 2GW of peak power is presented.
Abstract: Degenerated optical parametric amplification (OPA) is a well known technique to achieve broadband amplification necessary to generate ultrashort pulses. Here we present a parametric amplifier pumped by the frequency doubled output of a state-of-the-art fiber chirped pulse amplification system (FCPA) delivering mJ pulse energy at 30 kHz repetition rate and 650 fs pulse duration. The parametric amplifier and the FCPA system are both seeded by the same Yb:KGW oscillator. Additional spectral broadening of the OPA seed provides enough bandwidth for the generation of ultrashort pulses. After amplification in two 1mm BBO crystals a pulse energy of 90µJ is yielded at 30 kHz. Subsequent compression with a sequence of chirped mirrors shortens the pulses to 29 fs while the pulse energy is as high as 81µJ resulting in 2GW of peak power.
TL;DR: In this article, a multi-stage barium nitrate Raman shifter-amplifier was added to a conventional Ti:sapphire chirped pulse amplification system.
Abstract: We report generation and compression of millijoule-level first Stokes sideband (873nm) of 800nm TW pulses by inserting a multi-stage barium nitrate Raman shifter-amplifier into a conventional Ti:sapphire chirped pulse amplification system.
TL;DR: In this article, the authors report on the experimental proof-of-principle demonstration of the ultrashort pulse single-pass beta-barium borate, BBO optical parametric amplifier pumped by two mutually incoherent laser sources.
Abstract: We report on the experimental proof-of-principle demonstration of the ultrashort pulse single-pass beta-barium borate, BBO optical parametric amplifier pumped by two mutually incoherent laser sources. We show that the amplified signal at 1054 nm gains energy from both pump pulses with wavelengths of 680 and 527 nm, respectively, with overall energy conversion of 36%, and exhibits low wavefront distortions and improved energy stability in the gain saturation regime.
01 May 2008
TL;DR: In this article, a chirped-pulse laser has been constructed to seed the large Beamlet type Nd:Phosphate glass slab amplifiers in order to achieve multi-Joule operation.
Abstract: To enhance radiographic capabilities on its Z-Accelerator, Sandia National Laboratories is incorporating a petawatt laser system into the existing Z-Backlighter laser facility. A chirped-pulse laser has been constructed to seed the large Beamlet type Nd:Phosphate glass slab amplifiers. This seed laser consists of an optical parametric chirped pulse amplification (OPCPA) system joined to a Nd:Phosphate glass rod amplifier in order to achieve multi-Joule operation. After injection into the main slab amplifiers up to 500 J of chirped pulse energy is achieved. Two compressor options are available for this output: a lower energy compressor for 100TW (50 J/500 fs) operation and a higher energy compressor for 1PW (500 J/500 fs) operation. While the higher energy compressor is under construction, the 100 TW system is now operational and can achieve focal intensities up to 1019 W/cm2.
TL;DR: In this paper, a short-pulse laser has been constructed to seed the larger Beamlet type Nd:phosphate glass slab amplifiers, which achieved focal intensities up to 10 18 W/cm 2 at a repetition rate of once every 20min and has been applied to produce k-alpha X-rays in copper.
TL;DR: In this article, a carrier to envelope phase stable optical parametric chirped pulse amplification source in the mid-infrared was proposed, using a fully three dimensional OPCPA code.
Abstract: We present a design for a novel carrier to envelope phase stable optical parametric chirped pulse amplification source in the mid-infrared. We calculate the amplification of a 3.1µm seed pulse, generated via DFG from a two-colour fibre laser, using a fully three dimensional OPCPA code. We combine this with a ray-tracing code to model pulse compression using a grating compressor and a deformable mirror for programmable phase compensation. The simulation models the complete system based on FROG measurements of the commercially available fibre laser, ensuring the simulation is realistic. The obtained results indicate energetic pulses of 56 fs duration, corresponding to 5.2 cycles, can be produced with calculated pulse energies of up to 9.6µJ at a central wavelength of 3.3µm.
27 Jan 2008
TL;DR: The Petawatt Field Synthesizer (PFS) at MPQ will deliver few-cycle pulses at petawatt power as mentioned in this paper, using OPCPA and a diode-pumped, CPA Yb:YAG pump laser.
Abstract: The Petawatt Field Synthesizer (PFS) at MPQ will deliver few-cycle pulses at Petawatt power. Short-pulse OPCPA and a diode-pumped, CPA Yb:YAG pump laser are key technologies, and results of the ongoing development will be presented.
TL;DR: Both the simulation and experimental results indicate that the LBO has a great potential as nonlinear medium in power amplifier for TW to PW noncollinear optical parametric chirped pulse amplification (NOPCPA) systems.
Abstract: Ultrabroadband visible noncollinear optical parametric amplification (NOPA) was achieved in an LBO crystal, with a continuum seed pulse generated from a sapphire plate. The spectral bandwidth of the amplified visible pulse was about 200 nm, which can support sub-5 fs pulse amplification. An amplified output of 0.21 microJ with an average gain of about 210 was achieved. This provides, to the best of our knowledge, the first-time demonstration of such broadband amplification with a biaxial nonlinear optical crystal. Both the simulation and experimental results indicate that the LBO has a great potential as nonlinear medium in power amplifier for TW to PW noncollinear optical parametric chirped pulse amplification (NOPCPA) systems.
TL;DR: In this paper, a chirped-pulse amplification system was demonstrated, which was able to produce 25 μJ compressed pulses at a center wavelength of======1552.5 nm.
Abstract: We demonstrate a chirped-pulse amplification system generating 25 μJ compressed pulses at a center wavelength of
1552.5 nm. The seed module and the amplifier chain are all in-fiber (with a few small fiber-pigtailed free-space
components), followed by a free-space diffraction grating pulse compressor. The amplifier chain contains a pre-amplifier
and a booster whose gain fibers are 45/125 μm core/cladding-diameter, core-pumped Er-doped fibers. The pump lasers
for both amplifiers are single-mode 1480 nm Raman lasers capable of up to 8 W output. The seed module generates up
to 2 ns chirped pulses that are amplified and subsequently compressed to <800 fs duration. At a repetition rate of 50 kHz,
the 2 ns pulses from the seed module were amplified to 72 μJ, resulting in 25 μJ after pulse compression. The
corresponding peak power levels after the amplifier chain and compressor were 36 kW and 31 MW, respectively.
04 May 2008
TL;DR: Astra Gemini is a dual-beam petawatt Ti:sapphire laser at the Rutherford Appleton Laboratory in the U.K. as mentioned in this paper reported measurements characterising the laser beam quality, pulse energy, and pulse duration of the first beam line.
Abstract: Astra Gemini is a dual-beam petawatt Ti:sapphire laser at the Rutherford Appleton Laboratory in the U.K. We report measurements characterising the laser beam quality, pulse energy, and pulse duration of the first beam line.
04 May 2008
TL;DR: In this paper, a femtosecond fiber-CPA at 1.063 mum is demonstrated using broadband chirped-volume-Bragg-gratings for pulse stretching and compression.
Abstract: Femtosecond (~670 fs) fiber-CPA at 1.063 mum is demonstrated using broadband chirped-volume-Bragg-gratings for pulse stretching and compression. 32 W recompressed pulses are achieved corresponding to a 75% compression efficiency.