ABSTRACT
White light continuum seeded noncollinear optical parametric amplifier driven by Yb:KGW master oscillator power amplifier (MOPA) system is reported. The demonstrated design provides amplification of broadband pulses at 800 nm up to 20 µJ energy at 1 kHz repetition rate and can be used as simple and reliable frontend source for systems producing high intensity few-cycle pulses. The amplified spectral bandwidth allows for <7 fs pulse durations and preliminary compression of partial spectrum yields sub-10 fs pulse.
ABSTRACT
We report on the generation of sub-30-fs near-IR light pulses by means of broadband four-wave parametric amplification in fused silica. This is achieved by frequency downconversion of visible broadband pulses provided by a commercial blue-pumped beta-barium borate crystal-based noncollinear optical parametric amplifier. The proposed method produces the IR idler pulses with energy up to â¼20 µJ and tunable in wavelength from 1 to 1.5 µm. The shortest pulse duration is 17.6 fs, measured at 1.2 µm.
Subject(s)
Infrared Rays , Optical Phenomena , Borates/chemistry , Time FactorsABSTRACT
We report on the generation of approximately 30-fs ultraviolet pulses with approximately 10 microJ energy by means of four-wave optical parametric chirped pulse amplification in fused silica. The four-wave optical parametric amplifier is pumped by the second-harmonic of the Ti:sapphire laser and is seeded by visible broadband chirped signal pulses. The idler pulses are produced in the ultraviolet by four-wave mixing and are compressed in a medium with normal group velocity dispersion.
ABSTRACT
We report on what is to our knowledge the first observation of the parametric fluorescence in bulk nonlinear crystals excited by commercial high-brightness incoherent blue LED.
ABSTRACT
Efficient broadband four-wave optical parametric amplification in bulk Kerr medium (fused silica) is demonstrated by means of noncollinear phase matching and cylindrical focusing geometry without the onset of beam breakup and filamentation. Amplified signal energy as high as 180 microJ with 1 ps, 1.8 mJ pumping at 1,055 nm is achieved with pump-to-signal energy conversion close to 10%. More than 70 nm FWHM parametric gain bandwidth around 740 nm is demonstrated without imposing angular dispersion on the frequency components of the broadband seed signal.
ABSTRACT
We report on the experimental observations of on-axis spectral broadening arising from self-focusing of the axicon-generated femtosecond Bessel beam in water. The observed spectral broadening is interpreted by a nonlinearly phase-matched four-wave mixing process involving the intense conical pump, the axial signal and a conical idler wave.
ABSTRACT
We report on highly efficient four-wave optical parametric amplification in a water cell pumped by an elliptically shaped, ultrashort pulsed laser beam under non-collinear phase-matching configuration. Energy conversion from pump to parametric waves as high as 25 % is obtained owing to the achievement of 1-dimensional spatial-soliton regime, which guarantees high intensity over a large interaction length and ensures high beam quality.
ABSTRACT
We investigate ultrashort laser pulse filamentation within the framework of spontaneous X Wave formation. After a brief overview of the filamentation process we study the case of an intense filament co-propagating with a weaker seed pulse. The filament is shown to induce strong Cross-Phase-Modulation (XPM) effects on the weak seed pulse: driven by the pump, the seed pulse undergoes pulse splitting with the daughter pulses slaved to their pump counterparts. They undergo strong spatio-temporal reshaping and are transformed into XWaves traveling at the same group velocities as the pump split-off pulses. In the presence of a gain mechanism such as Four-Wave-Mixing or Stimulated Raman Scattering, energy is then transferred from the pump filament leading to amplification of the seed X Wave and formation of a temporally compressed intensity peak.ABSTRACT
Excitation of unbalanced-Bessel beams by a gradual increase of nonlinearity in a water sample outlines the achievement of the first ever observed quasimonochromatic wave packet that propagates stably for hundreds of Rayleigh lengths in a focusing and dispersive Kerr medium, i.e., in the absence of spectral broadening and conical emission. A modulational instability analysis reveals the key role of nonlinear dissipation in quenching the growth of spatiotemporal unstable modes.
ABSTRACT
We predict that in traveling-wave degenerate parametric downconversion the Bessel beam pump stimulates the appearance of a nondiffracting X-wave from quantum noise amplification. Numerical simulation results of downconversion in ADP crystal are presented, along with preliminary experimental data.
ABSTRACT
Measurements of the spatio-temporal and far-field profiles of ultrashort laser pulses experiencing conical emission, continuum generation, and beam filamentation in a Kerr medium outline the spontaneous formation of wave packets with X -like features, thus supporting recent numerical results [M. Kolesik, E. Wright, and J. Moloney, Phys. Rev. Lett. 92, 253901 (2004)]. Numerical simulations show good agreement with experimental data.
Subject(s)
Lasers , Models, Chemical , Nephelometry and Turbidimetry/methods , Radiometry/methods , Water/chemistry , Computer Simulation , Radiation Dosage , Scattering, RadiationABSTRACT
The concept of optical parametric chirped-pulse amplification is applied to attain pulses with energies up to 8 mJ and a bandwidth of more than 100 THz. Stretched broadband seed pulses from a Ti:sapphire oscillator are amplified in a multistage noncollinear type I phase-matched beta-barium borate parametric amplifier by use of an independent picosecond laser with lock-to-clock repetition rate synchronization. Partial compression of amplified pulses is demonstrated down to a 10-fs duration with a down-chirped pulse stretcher and a nearly lossless compressor comprising bulk material and positive-dispersion chirped mirrors.
ABSTRACT
We have monitored the space-time transformation of a 150-fs pulse undergoing self-focusing and filamentation in water, by means of the nonlinear gating technique. We have observed that pulse splitting and subsequent recombination apply to axial temporal intensity only, whereas the space-integrated pulse profile preserves its original shape.
ABSTRACT
The spatiotemporal intensity profile of a 100-fs wave packet at the output of a X2 crystal, tuned for mismatched second-harmonic generation, is probed via sum-frequency generation with a compressed, 20-fs pulse, revealing the appearance of an X-type wave shape.
ABSTRACT
We investigate experimentally the competition between spatial and temporal breakup due to modulational instability in chi((2)) nonlinear mixing. The modulation of the wave packets caused by the energy exchange between fundamental and second-harmonic components is found to be the prevailing trigger mechanism which, according to the relative weight of diffraction and dispersion, leads to the appearance of a multisoliton pattern in the low-dimensional spatial or temporal domain.
ABSTRACT
X waves, spatiotemporal generalization of the monochromatic Bessel- (or Durnin-) type beams, are known in linear acoustic, microwave and optics for their unique property of defeating both spatial and temporal spreadings. Recently, we brought to the attention that X-type waves are also the key to understand the spatiotemporal dynamics observed in the nonlinear (high intensity) regime. Indeed, X waves represent the normal-propagation mode for a wide class of parametric interactions described by hyperbolic nonlinear models featuring spatial self-focusing and temporal self-broadening. Here, we provide a complete and detailed description of the experiment in which the spontaneous appearance of X waves has been observed. The experiment concerns frequency doubling of a 170-fs, 50-microm standard laser wave packet in a 22-mm lithium triborate crystal, tuned for second-harmonic generation with positive phase mismatch, positive group-velocity dispersion, and large group-velocity mismatch. Conventional beam-profile and autocorrelation measurements at the crystal output face show evidence of spatiotemporal self-trapping. The characterization of the free-space propagation reveals sub-Gaussian diffraction and pulse broadening, consistent with the presence of angular dispersion. Space-resolved autocorrelations indicate the generation of an X-type profile.
ABSTRACT
We observe the formation of an intense optical wave packet fully localized in all dimensions, i.e., both longitudinally (in time) and in the transverse plane, with an extension of a few tens of fsec and microns, respectively. Our measurements show that the self-trapped wave is an X-shaped light bullet spontaneously generated from a standard laser wave packet via the nonlinear material response (i.e., second-harmonic generation), which extend the soliton concept to a new realm, where the main hump coexists with conical tails which reflect the symmetry of linear dispersion relationship.
ABSTRACT
Nonlinear optical media that are normally dispersive support a new type of localized (nondiffractive and nondispersive) wave packets that are X shaped in space and time and have slower than exponential decay. High-intensity X waves, unlike linear ones, can be formed spontaneously through a trigger mechanism of conical emission, thus playing an important role in experiments.
ABSTRACT
It is shown that in the paraxial approximation the conditions for noncollinear phase matching for three-wave parametric interaction in a nonlinear crystal coincide with the conditions for generation of focus wave modes. As a result, the creation of broadband localized optical fields (pulsed beams without diffraction and dispersion spreading) inside the crystals of parametric generators is feasible.
ABSTRACT
The conditions for creation of broadband localized optical fields (Bessel X pulses and focus wave modes) in dispersive media are analyzed. It is shown that transmission of focus wave modes with subcycle pulse durations through fused silica is possible.