Showing papers by "Andrius Baltuška published in 2008"
TL;DR: In this paper, it was shown that angularly asymmetric tunneling from the states can be mapped onto variations of high harmonic intensities and that near-circularly polarized isolated attosecond extreme ultraviolet or x-ray pulses can be produced.
Abstract: We numerically demonstrate so-far undescribed features in ionization and high harmonic generation from bound states with nonvanishing electronic angular momentum. The states' modified response to a strong laser pulse can be exploited for novel measurement and pulse production schemes. It is shown that angularly asymmetric tunneling from the states can be mapped onto variations of high harmonic intensities and that near-circularly polarized isolated attosecond extreme ultraviolet or x-ray pulses can be produced.
58 citations
01 Dec 2008
TL;DR: In this paper, the authors measured the absorption, photoluminescence spectra and CW lasing parameters of an Yb3+-and Na+-codoped CaF2 laser crystal in the temperature range from 5 K to 290 K.
Abstract: Absorption, photoluminescence spectra and CW lasing parameters of an Yb3+- and Na+-codoped CaF2 laser crystal are measured in the temperature range from 5 K to 290 K. The crystal appears to be a promising host for broadband multi-mJ kHz CW-pumped regenerative amplification.
41 citations
TL;DR: Spectral narrowing of nearly chirp-free 50-fs pulses delivered by a diode-pumped ytterbium solid-state laser (Yb DPSSL) is experimentally demonstrated using an anomalously dispersive, highly nonlinear photonic-crystal fiber (PCF).
Abstract: Spectral narrowing of nearly chirp-free 50-fs pulses delivered by a diode-pumped ytterbium solid-state laser (Yb DPSSL) is experimentally demonstrated using an anomalously dispersive, highly nonlinear photonic-crystal fiber (PCF). The ratio of spectral narrowing and the accompanying temporal pulse broadening are controlled by the peak power of Yb DPSSL pulses at the input of the fiber.
32 citations
TL;DR: In this paper, a general concept of using the spatial information encoded in the time-dependent polarization of high harmonic radiation generated by orthogonally polarized two-color laser fields is described.
Abstract: We describe a general concept of using the spatial information encoded in the time-dependent polarization of high harmonic radiation generated by orthogonally polarized two-color laser fields. The main properties of recolliding electron wave packets driven by such fields are reviewed. It is shown that in addition to the recollision energy the angle of recollision of such wave packets, which is directly mapped onto the polarization direction of the emitted high harmonic radiation, varies on a sub-laser-cycle time-scale. Thus, a mapping between the polarization angle and the frequency of the emitted radiation is established on an attosecond time scale. While the polarization angle encodes the spatial properties of the recollision process, the frequency is linked to time via the well-known dispersion relations of high harmonic generation. Based on these principles, we show that in combination with polarization selective detection the use of orthogonally polarized drive pulses for high harmonic generation permit one to construct spatially resolved attosecond measurements. Here, we present two examples of possible applications: (i) a method for isolating a single attosecond pulse from an attosecond pulse train which is more efficient than the cut-off selection method, and (ii) a technique for orbital tomography of molecules with attosecond resolution.
26 citations
TL;DR: In this article, an accurate broadband compensation of the stretcher-compressor dispersion in fiber laser sources of high-peak-power ultrashort light pulses has been demonstrated.
Abstract: Photonic-crystal fibers (PCFs) with a specifically designed dispersion profile and nonlinearity are shown to enable an accurate broadband compensation of the stretcher-compressor dispersion in fiber laser sources of high-peak-power ultrashort light pulses. We demonstrate that the nonlinear phase shift in such systems can partially compensate for the fourth-order dispersion, allowing the stretcher—compression group delay to be compensated up to the fourth-order dispersion terms by using a sequence of only two fibers—a standard optical fiber and a PCF.
4 citations
27 Jan 2008
TL;DR: In this paper, a combination of a 1030-nm 200-fs Yb-and a 1064-nm 60-ps Nd amplifier seeded with a common Yb oscillator was used to obtain a 35-THz-wide parametric amplification at 1.5 μm with the energy of 10 mJ.
Abstract: Efficient infrared 35-THz-wide parametric amplification at 1.5 μm with the energy of ~10 mJ is obtained in a 4-stage OPCPA using a combination of a 1030-nm 200-fs Yb- and a 1064-nm 60-ps Nd amplifier seeded with a common Yb oscillator.
3 citations
27 Jan 2008
TL;DR: In this article, a CaF2 crystal was used for broadband multi-mJ sub-kHz cw-pumped regenerative amplification with a 980-nm laser diode in the temperature range from 70 K to 290 K.
Abstract: Absorption, photoluminescence spectra and cw lasing parameters of Yb3+- and Na+-codoped CaF2 laser crystal pumped with a 980-nm laser diode are measured in the temperature range from 70 K to 290 K. The crystal appears to be a promising host for broadband multi-mJ sub-kHz cw-pumped regenerative amplification.
3 citations
27 Jan 2008
TL;DR: In this paper, the authors report the development of a 1-kHz OPCPA system, generating carrier-envelope-phase-stabilized 350-µJ 20-fs pulses around 2.1 µm with suppressed superfluorescence.
Abstract: We report the latest development of a 1-kHz OPCPA system, generating carrier-envelope-phase-stabilized 350-µJ 20-fs pulses around 2.1 µm with suppressed superfluorescence. A proof-of-principle high-harmonic-generation experiment in argon was conducted, producing photons up to 250 eV.
1 citations
01 Dec 2008
TL;DR: In this article, a femtosecond DPSS Yb technology and a picosecond Nd:YAG pump laser were used for high-field applications delivering 10mJ ~40fs pulses at 15 mum.
Abstract: We report on a 4-stage OPCPA system for high-field applications delivering 10-mJ ~40-fs pulses at 15 mum The system is based on a fusion of femtosecond DPSS Yb technology and a picosecond Nd:YAG pump laser In a first preliminary filamentation experiment in xenon, we observe spectral broadening of the recompressed multi-mJ 15 mum pulses
25 Nov 2008
TL;DR: In this paper, a carrier-envelope phase-stable 650-muJ 15-fs pulses around 2.1 mum were generated using a seed-spectral-shaping method.
Abstract: We report the latest development of an OPCPA system, generating carrier-envelope-phase-stable 650-muJ 15-fs pulses around 2.1 mum. A novel seed-spectral-shaping method is used to resolve the non-trivial problem of ascertaining the true amplified signal energy.
TL;DR: In this article, a simple method to reduce the absorption recovery time of the InGaN/GaN quantum well saturable absorber was demonstrated, where the recovery time was effectively controlled by controlling the crystal quality.
Abstract: In this work, a simple method to reduce the absorption recovery time of the InGaN/GaN quantum well saturable absorber was demonstrated. The recovery time of the saturable absorber grown by metal organic chemical vapor deposition was effectively controlled by controlling the crystal quality. Transmission electron microscopy results showed that, for saturable absorbers with reduced GaN buffer thicknesses, increased dislocations were introduced into the quantum well regions. The degraded crystal quality would therefore cause an increased density of nonradiative recombination centers, which were responsible for the fast recovery of the absorption. In addition, with the as-grown thin GaN buffers, the severe interference-induced reflectivity fluctuations were successfully suppressed.
04 May 2008
TL;DR: In this article, an interferometrically stable pulse multiplexing-amplification-recombination scheme for direct laser amplification of picosecond pulses is presented.
Abstract: We demonstrate an interferometrically stable pulse multiplexing-amplification-recombination scheme for direct laser amplification of picosecond pulses. Switching from single pulse amplification to the burst mode increases extraction efficiency, gain in cw-pumped crystals and output energies.
04 May 2008
TL;DR: In this paper, a 3-stage OPCPA using a combination of a 1030-nm 200-fs Yb-and a 1064-nm 60-ps Nd amplifier seeded with a common Yb oscillator was presented.
Abstract: Efficient infrared 35-THz-wide parametric amplification with energies above 3 mJ is obtained in a 3-stage OPCPA using a combination of a 1030-nm 200-fs Yb- and a 1064-nm 60-ps Nd amplifier seeded with a common Yb oscillator.
TL;DR: In this paper, an all-optical technique for mapping sub-cycle tunnel ionization in gas based on a cross-correlation measurement of Brunel-type harmonics detected in the direction of a weak probe pulse to separate them from recollision-driven harmonics is presented.
Abstract: We demonstrate an all-optical technique for mapping sub-cycle tunnel ionization in gas based on a cross-correlation measurement of Brunel-type harmonics detected in the direction of a weak probe pulse to separate them from recollision-driven harmonics.
25 Nov 2008
TL;DR: In this article, a femtosecond DPSSL Yb technology and a picosecond Nd:YAG pump laser are combined for high-field applications, delivering 10mJ 40-fs pulses at 1.5 mum.
Abstract: We report on a 4-stage OPCPA for high-field applications delivering 10-mJ 40-fs pulses at 1.5 mum. The system is based on a fusion of a femtosecond DPSSL Yb technology and a picosecond Nd:YAG pump laser.