共查询到20条相似文献,搜索用时 15 毫秒
1.
C. Jordan K. A. Stankov G. Marowsky E. J. Canto-Said 《Applied physics. B, Lasers and optics》1994,59(4):471-473
Femtosecond pulses at 496 nm were Raman-shifted in methane with 20% efficiency. The pulse duration could be reduced up to 6.5 times from 560 fs at the fundamental to 85 fs at the Stokes frequency (580nm), which is the shortest pulse duration generated in this way. It was shown experimentally that chirped-pulse Raman scattering avoids the limitations arising from self-phase modulation. 相似文献
2.
Alexander I. Vodchits Valery P. Kozich Valentin A. Orlovich 《Optics Communications》2006,260(1):307-310
Optical parametric amplification of multi-frequency seed pulses generated in a mixture of compressed hydrogen and methane by stimulated Raman scattering of 1 ps, 1 kHz laser pulses at 395.8 nm has been studied. Efficient generation of spectrally narrow ultrashort pulses with a spatial distribution close to the Gaussian profile of the pump beam was obtained in the visible and near infrared ranges. 相似文献
3.
Alexander I. Vodchits Valentin A. Orlovich Valery P. Kozich 《Optics Communications》2008,281(11):3190-3195
Applying gas recirculation in a high pressure cell, laser pulses of 1 ps at 400 nm and with a repetition rate of 1 kHz were frequency shifted by stimulated Raman scattering and amplification in methane gas at high pressure. We studied the influence of gas recirculation on the conversion efficiencies into the Stokes and anti-Stokes components as well as on their spatial distributions and spectral shapes using generator and generator-amplifier arrangements. For high pump energies, recirculation in the generator cell decreases conversion efficiency into the first Stokes component whereas it increases conversion into higher Stokes and anti-Stokes components. It results in a significantly improved spatial characteristics of the frequency-shifted radiation, however, is accompanied by a substantial spectral broadening. Using gas recirculation in the generator-amplifier arrangement we achieved a conversion efficiency into the first Stokes component of about 50% with highly improved spatial and spectral characteristics. 相似文献
4.
5.
H. Ohde S. Lin A. Minoh F. O. Shimizu M. Aono T. Suzuki 《Applied physics. B, Lasers and optics》1996,62(1):15-19
A down-conversion to the mid-infrared region by using Stimulated Electronic Raman Scattering (SERS) in potassium vapor is described. The pump radiation is a frequency-doubled regeneratively amplified Ti:Sapphire laser with a pulse duration of 2 ps, pulse energy of 0.2 mJ, and repetition rate of 10 Hz. With the pumping frequency tuned around the potassium 4s-5p transition, nearly transform-limited infrared radiation tunable between 2.2 and 3.4 m has been generated with a peak infrared energy of 12 µJ, corresponding to a quantum efficiency of 17%, and with a pulse duration of 2 ps. The present tuning range could be extended by extending the tuning range of the pump laser. In comparison, intense infrared radiation of 90 µJ energy but with a very narrow tunability around 2.9 m has also been generated by SERS in barium vapor. 相似文献
6.
A novel-high energy pulse compression system: generation of multigigawatt sub-5-fs pulses 总被引:2,自引:0,他引:2
M. Nisoli S. Stagira S. De Silvestri O. Svelto S. Sartania Z. Cheng M. Lenzner C. Spielmann F. Krausz 《Applied physics. B, Lasers and optics》1997,65(2):189-196
Received: 28 February 1997 / Revised version: 2 May 1997 相似文献
7.
A. Kummrow M. Wittmann F. Tschirschwitz G. Korn E.T.J. Nibbering 《Applied physics. B, Lasers and optics》2000,71(6):885-887
We demonstrate the generation of ultraviolet 33-fs pulses with a shot-to-shot energy fluctuation of less than 3% using sum
frequency mixing of visible pulses of a noncollinear optical parametric amplifier with sub-40-fs pulses of a 1-kHz Ti:sapphire-amplified
system. The pulses are transform-limited (ΔνΔτ=0.36) and tunable in the range from 315 nm to 355 nm with energy above 1 μJ
(2.6 μJ at 330 nm).
Received: 21 July 2000 / Published online: 8 November 2000 相似文献
8.
J. Limpert T. Gabler A. Liem H. Zellmer A. Tünnermann 《Applied physics. B, Lasers and optics》2002,74(2):191-195
In a fiber amplifier, spectral compression due to self-phase modulation is demonstrated for ultrashort pulses. We report the
generation of near-transform-limited picosecond pulses with peak powers of several kW at a repetition rate of 74 MHz and diffraction-limited
beam quality in a Yb-doped fiber amplifier when seeding with a negative chirped pulse.
Received: 17 September 2001 / Revised version: 22 November 2001 / Published online: 17 January 2002 相似文献
9.
Self-compression of multi-millijoule femtosecond laser pulses and dramatic increase of the peak intensity are found in pressurized helium and neon within a range of intensity in which the ionization modification of the material parameters by the pulse is negligible. The pulse propagation is studied by the (3 + 1)-dimensional nonlinear Schrödinger equation including basic lowest order optical processes - diffraction, second order of dispersion, and third order of nonlinearity. Smooth and well controllable pulse propagation dynamics is found. Construction of compressed pulses of controllable parameters at given space target point by a proper chose of the pulse energy and/or gas pressure is predicted. 相似文献
10.
A.M. Zheltikov 《Optics Communications》2009,282(5):985-987
The inertia of the Kerr-type nonlinear-optical response of bound electrons in solids is analyzed. It is shown that, in the case of wide-gap materials, away from the mid-gap frequency Eg/2?, Eg being the band gap, the inertia of this response becomes noticeable only for attosecond pulse features. However, near Eg/2?, where the inertia of bound-electron Kerr-type optical nonlinearity is enhanced by a strong dispersion of two-photon absorption and where the nonlinear refraction is especially strong, light pulses as long as tens and even hundreds of femtoseconds are expected to experience self-steepening and an asymmetric spectral broadening due to the retarded Kerr effect. 相似文献
11.
R. J. Heeman H. P. Godfried W. J. Witteman 《Applied physics. B, Lasers and optics》1995,60(5):479-484
High energy-conversion efficiencies in Stimulated Raman Scattering (SRS) are demonstrated both in experiments and by simulations for pump powers below SRS threshold. The scattering is induced by a short seed pulse at the Stokes frequency, the pulse width of which is much shorter than the pump pulse width and which is comparable with the medium's dephasing time. 相似文献
12.
Visible femtosecond (fs) laser pulses have been obtained in a dye solution with a very simple traveling wave collinear configuration.
A femtosecond Ti:sapphire laser (790 nm) pumps the dye solution by two-photon absorption and simultaneously generates supercontinuum,
which seeds a light-amplification mechanism. Cross-correlation frequency-resolved optical gating measurements reveal a chirped
structure in the dye pulse. The shortest pulse duration achieved is 170 fs and the overall energy efficiency of the process
is typically 25%.
Received: 22 March 2001 / Revised version: 4 July 2001 / Published online: 19 September 2001 相似文献
13.
The signal and idler output of an optical parametric oscillator are mixed in LiIO3 and AgGaS2 crystals to generate infrared pulses with a repetition rate of 82 MHz and an average power of 500µW. The infrared pulses are tunable between 2.5 and 5.5 µm, have a duration of 200 fs and a peak-to-peak intensity fluctuation of less than 5 %. 相似文献
14.
Highly-chirped dissipative solitons of the cubic-quintic Ginzburg-Landau equation found in this work may provide a roadmap to design passively mode-locked laser oscillators that generate pulses of extremely high energy. We provide a region in the space of the system parameters where high-energy dissipative solitons are found, along with their typical spectral and temporal features. 相似文献
15.
We have developed a novel interferometric autocorrelator composed of only reflective elements, which functions as a beam splitter
and an optical delay line. Analytical expressions are derived to give second-order autocorrelation functions and deconvolution
factors for various conditions. The measurement of femtosecond laser pulses by interferometric autocorrelation is demonstrated
in the visible region. The results are compared with those by calculation.
Received: 9 December 2002
Revised version: 18 February 2003 / Published online: 5 May 2003
RID="*"
ID="*"Present address: Department of Physics, Tokai University, 1117 Kitakaname, Hiratsuka, Kanagawa 259-1207, Japan
RID="**"
ID="**"Corresponding author. Fax: +81-48/462-4682, E-mail: asuda@postman.riken.go.jp 相似文献
16.
Using the hydrodynamic model of semiconductor-plasmas and following the coupled-mode approach, a detailed analytical investigation is undertaken to study both steady-state and the transient Raman gain in transversely magnetized narrow band-gap semiconductors arising from electron density perturbations and molecular vibrations of the medium. Using the fact that the origin of stimulated Raman scattering (SRS) lies in the third-order susceptibility of the medium, we obtain an expression for the gain coefficient of the backward Stokes mode in steady-state and transient regimes and study the dependence of the magnetic field and pump pulse duration on its growth rate. The threshold pump intensity and optimum pulse duration for the onset of transient SRS are estimated. An externally applied magnetic field substantially enhances the transient SRS gain coefficient in narrow band-gap semiconductors, which can be of great use in the compression of scattered pulses. 相似文献
17.
In this paper, the multi-stage compression of picosecond pulses by cascaded quadratic nonlinearity is studied theoretically, and the dependence of pulse compression on phase-mismatch, laser intensity, and crystal characteristics has been discussed in detail. We demonstrate that the multi-stage pulse compression is much more efficient than the single-stage with a same total crystal length. Pulses as short as ∼150 fs can be generated by compressing 30-ps initial pulses in a two-stage configuration under the realistic crystal and laser conditions, and shorter pulses of ∼30 fs may be obtained by three-stage compression. Pulse compression performances with BiBO and BBO crystals are compared and discussed finally. 相似文献
18.
We describe a method of ultrashort-pulse and ultrafast-pulse-train generation through optical parametric amplification of a laser beat wave. Numerical simulation shows that 250-fs laser pulses at 1.55 μm are generated from a beat-wave seeded optical parametric amplifier pumped by a 30-ps laser at 1064 nm. The pulse compression is attributable to sideband generation and parametric amplification under group velocity mismatch. Our experimental result confirms efficient generation of comb-like sidebands for the mixing waves from such an optical parametric amplifier. 相似文献
19.
E. Goulielmakis G. Nersisyan N.A. Papadogiannis D. Charalambidis G.D. Tsakiris K. Witte 《Applied physics. B, Lasers and optics》2002,74(3):197-206
A novel application of a free-standing transmission grating as a beam splitter in a Michelson-type interferometer is described.
The arrangement can operate in the XUV and soft X-ray spectral region and, therefore, it is well suited for the characterization
of attosecond pulses. Using ray-tracing codes, we have analyzed three different setups in which spherical mirrors are employed
in conjunction with the transmission grating and have investigated in detail their dispersive characteristics. It is shown
that such an arrangement can be made to exhibit group-delay dispersion of ∼1 as2 while it provides two co-propagating and converging beams.
Received: 12 October 2001 / Revised version: 17 December 2001 / Published online: 7 February 2002 相似文献
20.
A.A. Babin D.V. Kartashov A.M. Kiselev V.V. Lozhkarev A.N. Stepanov A.M. Sergeev 《Applied physics. B, Lasers and optics》2002,75(4-5):509-514
. We report on the experimental and theoretical study of spectrum transformation and frequency blue-shift of femtosecond laser
pulses with intensities up to 2×1016 W/cm2, propagating in glass capillary tubes under gas ionization. Monomode optical guiding with 45% transmission efficiency is
demonstrated in a 100-μm-diameter, 20-cm length capillary. A broadening of the initial spectrum as much as several initial
spectrum widths is achieved. Besides the broadening, the mean frequency of the output radiation in the spectrum experiences
a blue-shift of up to several initial spectrum widths, caused by the non-stationary, non-linear process of gas ionization.
Our numerical simulations, in the form of a simple one-dimensional model for the propagation of intense laser pulses in gas-filled
capillaries, are in good qualitative agreement with the experimental results. These simulations show the possibility of significant
compression of an output pulse in a simple compression scheme (e.g. a piece of silica glass with normal dispersion), which
is very important for obtaining laser pulses with few optical cycles at the millijoule energy level.
Received: 25 September 2001 / Revised version: 6 December 2001 / Published online: 25 September 2002
RID="*"
ID="*"Corresponding author. Fax: +7-8312/363-792, E-mail: dekart@ufp.appl.sci-nnov.ru 相似文献