共查询到20条相似文献,搜索用时 31 毫秒
1.
Baozhen Zhao Yuxin Leng Cheng Wang Yongliang Jiang Juan Du Zhizhan Xu 《Optics Communications》2006,259(1):137-141
Optical parametric chirped pulse amplification with different pump wavelengths was investigated using LBO crystal, at signal central wavelength of 800 nm. According to our theoretical simulation, when pump wavelength is 492.5 nm, there is a maximal gain bandwidth of 190 nm centered at 805 nm in optimal noncollinear angle using LBO. Presently, pump wavelength of 492.5 nm can be obtained from second harmonic generation of a Yb:Sr5(PO4)3F laser. The broad gain bandwidth can completely support ∼6 fs with a spectral centre of seed pulse at 800 nm. The deviation from optimal noncollinear angle can be compensated by accurately tuning crystal angle for phase matching. The gain spectrum with pump wavelength of 492.5 nm is much better than those with pump wavelengths of 400, 526.5 and 532 nm, at signal centre of 800 nm. 相似文献
2.
We present a double-pass non-collinear optical parametric amplifier (NOPA) that delivers 4-fs visible–near-infrared pulses.
The paper discusses geometrical and temporal properties of the NOPA configuration, which allow us to broaden the gain band
of simultaneous parametric amplification in excess of 250 THz. The key elements of the bandwidth enhancement include (i) the
use of a broadband second-harmonic pump, (ii) optimization of the incidence angle of all monochromatic spectral components
of the pump in order to produce a favorable offset of the corresponding phase-matching curves, and (iii) selection of the
chirp rate and time delay between the stretched pump and seed pulses. We next devise a two-stage compressor that incorporates
a flexible mirror for adaptive pulse shaping and develop a simple and trustworthy feedback loop based on a one-dimensional
spectral measurement. Our rapid numerical algorithm for adaptive control of the flexible membrane is found superior to more
complex search routines that are less resistant to the fluctuations of the laser intensity. The automated optimization procedure
results in the generation of two-cycle pulses with a carrier wavelength at ∼600 nm. The absence of deep modulation on the
parametrically amplified spectrum in combination with the adaptive phase correction lead to a high quality of the temporal
profile and allow concentrating 90% of the pulse energy within only a 7.5-fs time window.
Received: 8 April 2002 / Revised version: 26 June 2002 / Published online: 25 September 2002
RID="*"
ID="*"Present address: Institut für Photonik, Technische Universit?t Wien, Gusshausstrasse 27, 1040 Vienna, Austria
RID="**"
ID="**"Corresponding author. Fax: +81-3/5841-4165, E-mail: kobayashi@phys.s.u-tokyo.ac.jp 相似文献
3.
S. Ito H. Nagaoka T. Miura K. Kobayashi A. Endo K. Torizuka 《Applied physics. B, Lasers and optics》2002,74(4-5):343-347
We have measured detailed thermal lensing in a power amplifier of a terawatt Ti:sapphire laser operating at 50 Hz. The thermal
lensing in the amplifier was evaluated by measuring the optical path difference (OPD) using a Shack–Hartmann-type wavefront
sensor. It was found that the radial dependence of the OPD was almost quadratic in the pumping region, despite inhomogeneous
pumping. Therefore, a simple spherical lens or convex mirror effectively compensates for the thermal lens in our amplifier.
We found that the thermal lens profile was temporally stable, and did not degrade the pointing stability of the amplified
laser pulses. We also found that the time constant of the thermal distortion in our power amplifier was approximately 0.5 s.
Received: 3 September 2001 / Revised version: 23 January 2002 / Published online: 14 March 2002 相似文献
4.
G. Anstett G. Göritz D. Kabs R. Urschel R. Wallenstein A. Borsutzky 《Applied physics. B, Lasers and optics》2001,72(5):583-589
We report on the reduction of the divergence and the spectral width of the output of a 355 nm pumped pulsed optical parametric
oscillator (OPO) of β-barium borate (BBO). Detailed theoretical investigations indicated that type-IIphase matching in combination
with double-passing the pump beam should simultaneously reduce the spectral width and the divergence of the OPO output beam.
These predictions are confirmed in the experiments reported in this paper. In fact the bandwidth is reduced by more than a
factor of 20 to less than 0.1 nm. Simultaneously the divergence of the OPO waves is reduced in the phase matching plane by
more than a factor of 5 to 1.0 mrad. The small divergence and the reduced bandwidth allows efficient frequency doubling of
the 5-ns-long visible OPO signal pulses into the UV. Doubling in a 7-mm-long BBO crystal provided conversion efficiencies
of up to 35%.
Received: 21 August 2000 / Revised version: 11 December 2000 / Published online: 21 March 2001 相似文献
5.
We describe a laser system that readily provides radiation tunable from 2 μm in the infra-red to 35 nm in the extreme ultraviolet
spectral range. The broad spectral range is covered through a range of non-linear processes such as Raman shifting and high-order
harmonic generation. Pulses with duration of tens of picoseconds are obtained. The relative bandwidth of the radiation is
δλ/λ=10-4, comparable with what can be achieved by using high-resolution monochromators at state-of-the-art synchrotron beamlines.
We discuss different methods for characterising the radiation in this wide wavelength regime. We also discuss the capabilities
of the system from the measured parameters.
Received: 12 December 2000 / Revised version: 8 March 2001 / Published online: 27 April 2001 相似文献
6.
Transmission behavior in a photorefractive polymer film 总被引:2,自引:0,他引:2
When a p-polarized beam propagates through a high-performance photorefractive polymer composite, poly dimethyl-4-(4′-nitrophenylazo)benzene, its transmission behavior is influenced by three effects: the electroabsorption, the photorefractive
coupling with the reflected beam from the rear surface, and the amplified scattering. From the measurements on the incidence
angle dependence as well as the applied-electric-field dependence of the three effects, some conclusions are obtained. At
a small incidence angle with a low applied electric field, both the amplified scattering and the electroabsorption are small
whereas the coupling between the incident beam and the reflected beam plays a principal role. At a large incidence angle or
with a high poling electric field, the transmission is influenced mainly by the amplified scattering and the electroabsorption.
A poling electric field asymmetric loss to the amplification scattering is also observed.
Received: 18 November 1998 / Revised version: 10 February 1999 / Published online: 12 April 1999 相似文献
7.
We report on an optical parametric amplifier (OPA) based on two potassium titanyl phosphate (KTP) crystals in a walk-off compensating
geometry. An Nd:YLF regenerative amplifier at a 1-kHz repetition rate serves as the pump source. The seed beam is delivered
by a synchronously pumped frequency-stabilized optical parametric oscillator (OPO) based on periodically poled lithium niobate
(PPLN). At pump intensities of about 7 GW/cm2 large amplification factors of more than 104 were achieved, resulting in pulse energies of more than 450 μJ and 350 μJ for the signal and idler pulses, respectively,
at a 1-kHz repetition rate. In the saturation regime the time–bandwidth product increases from two to three times the Fourier
limit, with a pulse duration of 105 ps and a bandwidth of 12.7 GHz at the highest intensities employed.
Received: 2 November 2001 / Published online: 14 March 2002 相似文献
8.
An acoustic-optics programmable dispersive filter (AOPDF) was first employed to actively control the linearly polarized femtosecond pump pulse frequency chirp for supercontinuum (SC) generation in a high birefringence photonic crystal fiber (PCF). By accurately controlling the second order phase distortion and polarization direction of incident pulses, the output SC spectrum can be tuned to various spectral energy distributions and bandwidths. The pump pulse energy and bandwidth are preserved in our experiment. It is found that SC with broader bandwidth can be generated with positive chirped pump pulses except when the chirp value is larger than the optimal value, and the same optimal value exists for the pump pulses polarized along the two principal axes. With optimal positive chirp, more than 78% of the pump energy can be transferred to below 750 nm. Otherwise, negative chirp will weaken the blue-shift broadening and the SC bandwidth. 相似文献
9.
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
10.
We present a new experimental setup for the optical storage of information via refreshing by inverse seeding (OSIRIS), which
allows a sixfold increase of the storage time of holograms in a Ba0.77Ca0.23TiO3 crystal (BCT). The setup consists of two four-wave mixing processes with common amplified signal waves and phase-conjugated
(pc) waves. Temporal behaviours of the amplified and pc signal waves for the OSIRIS experiment as well as for the common four-wave
mixing experiment are compared and discussed. The solutions of coupled equations under the depleted-pump approximation are
obtained in order to estimate the pc reflectivities and coupling gains of gratings inside the crystal.
Received: 13 December 2000 / Revised version: 26 January 2001 / Published online: 27 April 2001 相似文献
11.
A.V. Mitrofanov A.A. Ivanov M.V. Alfimov A.A. Podshivalov A.M. Zheltikov 《Optics Communications》2007,280(2):453-456
Microjoule supercontinuum generation is demonstrated using a large-mode-area photonic-crystal fiber (PCF) pumped by an amplified stretched-pulse output of a mode-locked Cr:forsterite laser. A PCF with a mode area of 380 μm2 is employed to transform 300-fs Cr:forsterite laser pulses with a peak-power of a few megawatts into a supercontinuum radiation with a spectrum spanning from 700 to 1800 nm and a total energy of 1.15 μJ. 相似文献
12.
J. Darginavi?ius 《Optics Communications》2009,282(14):2995-384
We report on four-wave optical parametric amplification of the ultrashort ultraviolet light pulses in bulk fused silica and CaF2. Exact phase-matching in these isotropic media is achieved by means of non-collinear interaction with cylindrical beam focusing. Four-wave optical parametric amplifier efficiently operates in the UV spectral range with 1-ps laser pulses, delivering amplified signal energy exceeding 50 μJ using millijoule pump pulses in the visible (527 nm). Results of scanning of the parametric gain profile suggest that broad amplification bandwidth as wide as ∼20 nm (at FWHM) under these experimental settings is achieved, which might support amplification of sub-10-fs ultraviolet pulses with central wavelength around 330 nm. It is also shown experimentally and verified theoretically that the parametric gain profile exposes a distinct inhomogeneity and its bandwidth notably broadens due to effects of self- and cross-phase modulation imposed by the intense pump beam. 相似文献
13.
We theoretically demonstrate the achievement of narrow-band coherent anti-Stokes Raman scattering (CARS) signal by manipulating broad-band probe spectrum. The narrowing of the CARS signal depends on the spectrum bandwidth of the probe beam, and thus high-resolution CARS signal for a complicated quantum system can be obtained by the simple spectrum manipulation. Furthermore, the energy-level diagram for the complicated quantum system can also be labelled by measuring the CARS signal at a given frequency. 相似文献
14.
P. Mathey P. Jullien S.G. Odoulov O.A. Shinkarenko 《Applied physics. B, Lasers and optics》2001,73(7):711-715
Considerable slowing down is observed for both the temporal development of the coherent oscillation slightly above the threshold
and the refractive index grating decay slightly below the threshold for a semilinear photorefractive oscillator with two counter-propagating
pump waves. It is shown that in the vicinity of the threshold the reciprocal characteristic time is a linear function of deviation
from the threshold coupling strength. This behaviour is similar to an empirical Curie–Weiss law and points to the analogy
of the oscillation threshold to a second-order phase transition.
Received: 2 April 2001 / Revised version: 23 August 2001 / Published online: 7 November 2001 相似文献
15.
I.F. Salakhutdinov L. Kotačka H.J.W.M. Hoekstra J. Čtyroký V.A. Sychugov O. Parriaux 《Applied physics. B, Lasers and optics》2001,73(5-6):541-545
Abnormal reflecting mirror (ARM) structures, consisting of a corrugated optical waveguiding structure, can serve as a wavelength-selective
end mirror in a laser cavity. The ARM structure shows, for each wavelength in a certain region, 100% reflection at a certain
angle of incidence. In the vicinity of this angle the waveguide is resonantly excited, leading to strong enhancement of the
optical field in the layer structure, which is interesting for efficient second-harmonic generation (SHG). In this paper,
experimental results of a first prototype, exhibiting Čerenkov SHG, are reported.
Received: 16 May 2001 / Revised version: 28 August 2001 / Published online: 30 October 2001 相似文献
16.
Mid-infrared trace gas detection using continuous-wave difference frequency generation in periodically poled RbTiOAsO4 总被引:1,自引:0,他引:1
A tunable mid-infrared continuous-wave (cw) spectroscopic source in the 3.4–4.5 μm region is reported, based on difference
frequency generation (DFG) in a quasi-phase-matched periodically poled RbTiOAsO4 (PPRTA) crystal, DFG power levels of 10 μW were generated at approximately 4 μm in a 20-mm long PPRTA crystal by mixing two
cw single-frequency Ti:Al2O3 lasers operating near 713 nm and 871 nm, respectively, using a laser pump power of 300 mW. A quasi-phase-matched infrared
wavelength-tuning bandwidth (FWHM) of ∼12 cm-1 and a temperature tuning rate of 1.02 cm-1/°C were achieved. Experimental details regarding the feasibility of trace gas detection based on absorption spectroscopy
of CO2 in ambient air using this DFG radiation source are also described.
Received: 23 October 2000 / Revised version: 22 January 2001 / Published online: 27 April 2001 相似文献
17.
Diode-pumped Cr:LiCAF fs regenerative amplifier system seeded by an Er-doped mode-locked fiber laser
A fs regenerative amplifier based on Cr:LiCAF is demonstrated for the first time. With direct diode pumping, 8 μJ of pulse
energy are obtained directly from the amplifier. When seeded by an Er-doped fiber laser, the amplified seed pulses are compressed
down to 252 fs, limited by residual net third-order dispersion of the compression gratings and intracavity elements. Pulse
broadening due to second- and third-order dispersion is theoretically investigated and compared to experimental results. Dispersion
generated by the geometrical cavity arrangement is measured experimentally.
Received: 19 November 2001 /
Revised version: 28 January 2002 / Published online: 14 March 2002 相似文献
18.
N.A. Papadogiannis C. Kalpouzos E. Goulielmakis G. Nersisyan D. Charalambidis F. Augé F. Weihe Ph. Balcou 《Applied physics. B, Lasers and optics》2001,73(7):687-692
A compact, versatile table-top kilohertz source of coherent extreme-ultraviolet (XUV) radiation in the wavelength region 18–100 nm,
based on high-order harmonic generation from noble gases induced by a 40-femtosecond Ti:sapphire laser system, is presented.
The XUV beamline delivers at its output 108 photons/s at a wavelength of 23 nm. The monochromatized XUV radiation is directly focused onto a 10-2-mm2 spot by a toroidal grating, allowing one to reach intensities higher than 106 W/cm2. Optimization results are presented for a new XUV-generating geometry, utilizing a ‘semi-infinite’ quasi-static gas cell
and strong focusing. In those conditions, we observe an anomalous inversion between the cutoffs of argon and krypton, with
the krypton spectrum extending to much higher orders than expected in an adiabatic limit.
Received: 9 July 2001 / Revised version: 1 August 2001 / Published online: 7 November 2001 相似文献
19.
M. Nisoli G. Sansone S. Stagira C. Vozzi S. De Silvestri O. Svelto 《Applied physics. B, Lasers and optics》2002,75(6-7):601-604
A novel spectral broadening technique, based on hollow-fiber cascading, is reported, which allows the generation of a supercontinuum
extending to a bandwidth exceeding 510 THz with excellent spatial beam quality. High-peak-power, sub-7-fs light pulses tunable
from the visible to the near infrared have been generated by compression of portions of the supercontinuum, employing different
sets of chirped mirrors.
Received: 11 July 2002 / Revised version: 3 September 2002 / Published online: 15 November 2002
RID="*"
ID="*"Corresponding author. Fax: +39-02/2399-6126, E-mail: mauro.nisoli@fisi.polimi.it 相似文献
20.
We demonstrate experimentally the bistable nature of the bright resonator solitons in a semiconductor microresonator with
mixed absorptive/defocusing nonlinearity and show that they can be written and erased by incoherent local optical injection.
Received: 22 February 2001 / Published online: 27 April 2001 相似文献