共查询到20条相似文献,搜索用时 46 毫秒
1.
M. Jelínek W. Kulisch M.P. Delplancke-Ogletree J. Lancok L. Jastrabík D. Chvostová C. Popov J. Bulír 《Applied Physics A: Materials Science & Processing》2001,73(2):167-170
Nitrogen-rich carbon nitride films were prepared by three different deposition methods on fused silica, stainless steel and
silicon cantilever substrates. Their optical properties were studied by spectroscopic ellipsometry and UV spectrometry. Mechanical
properties such as plastic and Vickers microhardness, Young’s modulus, adhesion and film stress were also tested. The results
were compared with the properties of films with lower nitrogen concentrations.
Received: 26 January 2001 / Accepted: 29 January 2001 / Published online: 3 May 2001 相似文献
2.
A model for the interaction of near-infrared laser pulses with metal powders in selective laser sintering 总被引:4,自引:0,他引:4
P. Fischer N. Karapatis V. Romano R. Glardon H.P. Weber 《Applied Physics A: Materials Science & Processing》2002,74(4):467-474
A thermal model of the interaction of pulsed near-infrared laser radiation from a Nd:YAG laser was made, taking the measured
powder properties such as reflectance, optical penetration depth and thermal conductivity into account. It allows an estimation
of the evolution of two different temperatures: the average temperature of the powder (taken over the grains in a volume given
by the laser beam diameter and the optical penetration depth) and the temperature distinction within a single grain. It showed
that in pulsed mode consolidation can be achieved at much lower average power as the surface of the powder particles are molten
but their cores remain at nearly room temperature. This leads to a much lower average temperature and therefore a dramatic
decrease in residual thermal stresses in the finished piece. The results of the model were experimentally tested and confirmed.
Received: 26 July 2001 / Accepted: 23 November 2001 / Published online: 23 January 2002 相似文献
3.
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
4.
F. De Filippo C. de Lisio P. Maddalena G. Lérondel T. Yao C. Altucci 《Applied Physics A: Materials Science & Processing》2001,73(6):737-740
Porous-silicon reflectance has been determined over a large energy range, from 1 eV to 16 eV, by combining a NIR/visible/UV
spectrometer with a new VUV light source as laser-harmonic radiation. The porous-silicon dielectric function was deduced from
reflectance measurements by Kramers–Kronig analysis. We point out that, for the first time, laser harmonics have been applied
in the optical characterization of materials as a new and suitable alternative to synchrotron radiation.
Received: 9 January 2001 / Accepted: 28 April 2001 / Published online: 20 June 2001 相似文献
5.
We have demonstrated efficient amplification of near-infrared, 0.83-μm and 1.06-μm light, in a photorefractive ring resonator
using Rh:BaTiO3. The optical power oscillating inside the ring exceeded the pump power by a factor of up to 2.34. The sensitivity of a ring
resonator to nanometer changes in its length was characterised using a piezo-mirror.
Received: 30 November 2000 / Revised version: 24 January 2001 / Published online: 20 April 2001 相似文献
6.
B. Wang C.-C. Sun T.-H. Yang P. Ye J.-Y. Chang 《Applied physics. B, Lasers and optics》2001,72(6):691-696
Anisotropic self-diffraction (ASD) under Bragg mismatch has been studied. We derive a solution that can describe well the
diffraction characteristics of the anisotropic self-diffraction under Bragg mismatch. The solution is useful for estimating
the Bragg constraint when the ASD is applied to optical information processing. Both the theory and the experiment are presented.
Received: 11 July 2000 / Revised version: 2 January 2001 / Published online: 30 March 2001 相似文献
7.
As a new method for measuring the spatial distribution of Bose–Einstein condensates, the magnetic resonance imaging (MRI)
method is proposed and studied in detail. The basic concepts, the resolution limit and the formalism of the MRI method are
presented. It is expected that a resolution higher than that in optical imaging methods can be obtained by using the MRI method.
Results of simulation of expected MRI signals for Bose–Einstein condensates containing dark solitons are also presented.
Received: 27 September 2001 / Revised version: 24 October 2001 / Published online: 17 January 2002 相似文献
8.
M. Greiner I. Bloch O. Mandel T.W. Hänsch T. Esslinger 《Applied physics. B, Lasers and optics》2001,73(8):769-772
Bose–Einstein condensates of rubidium atoms are transferred into one- and two-dimensional optical lattice potentials. The
phase coherence of the condensate wavefunction in the lattice potential is studied by suddenly releasing the atoms from the
trapping potential and observing the multiple matter-wave interference pattern of several thousand expanding quantum gases.
We show how arbitrary phase gradients can be mapped onto the periodic wavefunction through the application of a potential
gradient. Furthermore, the experimentally measured strength of the momentum components is compared to a theoretical model
of the condensate wavefunction in the lattice.
Received: 3 July 2001 / Revised version: 26 September 2001 / Published online: 23 November 2001 相似文献
9.
In this paper we report the results of an investigation into surface deformation caused by thermal effects during excimer
laser ablation of polyimide. Obvious surface deformation around hole entrances was observed during the experiment. The surface
topology and cross section of the ablated holes were analyzed using topography measurement tool and scanning electron microscopy.
It was shown that a micro-hump of 17 to 150 nm in height and 1 to 3 μm in width was formed above the level of the unablated
surface. The deformed surface showed rough and color-changed characteristics. An optical diffraction model was employed to
explain the cause of this kind of deformation. It was found that the ablating and heating by a near- and under-threshold laser
beam became a thermal effect in polyimide material ablation, which was contributed to by a diffraction effect of the optical
projection system.
Received: 9 October 2001 / Accepted: 17 October 2001 / Published online: 23 January 2002 相似文献
10.
This paper presents experimental evidence that orthogonally crossed dark soliton stripes form quasi-two-dimensional spatial
solitons with a soliton constant equal to that of singly charged optical vortices. Besides the pairs of oppositely charged
optical vortex solitons, the snake instability of the dark formation at moderate saturation is found to lead to generation
of steering mixed edge–screw phase dislocations with zero total topological charges.
Received: 26 October 1998 / Revised version: 19 January 1999 / Published online: 12 May 1999 相似文献
11.
E. Ozturk Y. Ergun H. Sari I. Sokmen 《Applied Physics A: Materials Science & Processing》2001,73(6):749-754
In this study, we report results of a self-consistent calculation obtained for the sub-band structure of Si δ-doped GaAs material
by using a new alternative method. We will discuss the influence of the δ-doping concentration and the δ-layerthickness on
the sub-band structure for a non-uniform distribution, which is taken as different from the known Gaussian distribution. The
confining potential, the sub-band energies, the sub-band occupations, and the Fermi energy have been calculated by solving
the Schr?dinger and Poisson equations by using the Airy functions self-consistently.
Received: 4 December 2000 / Accepted: 31 January 2001 / Published online: 26 April 2001 相似文献
12.
C. Weilnau W. Królikowski E.A. Ostrovskaya M. Ahles M. Geisser G. McCarthy C. Denz Y.S. Kivshar B. Luther-Davies 《Applied physics. B, Lasers and optics》2001,72(6):723-727
We review the generation of the recently predicted multi-component spatial optical solitons in a saturable nonlinear bulk
medium. We present numerical simulations for an effectively isotropic model and experimental results for a set of different
combinations of a Gaussian beam co-propagating incoherently with a beam of a more complex internal structure, such as a higher
order transverse laser mode. We discuss the different formation processes and the general properties of a variety of different
dipole-mode composite solitons and expand our investigations to the generation of a quadrupole-mode composite soliton.
Received: 1 December 2000 / Revised version: 12 January 2001 / Published online: 21 March 2001 相似文献
13.
S. Marchetti M. Martinelli R. Simili M. Giorgi R. Fantoni 《Applied physics. B, Lasers and optics》2001,72(8):927-930
A simple method to produce sub-ns pulses of laser radiation with wavelength ranging from middle infrared (MIR) to millimeter
(MM) is experimentally demonstrated. The system operates with a single OSS (optical semiconductor switching) driven by a ns
Nd laser. Pulse control is produced by varying the distance of a mirror from an OSS used as a cavity dumping. The effectiveness
of this sub-ns MM pulse generation is larger than the one observed in other schemes. Pulses with 500-ps FWHM and 15-W power
were produced at 2.65 mm with a time compression compared to the 2-ns FWHM of the 1.06-μm driving laser.
Received: 30 October 2000 / Revised version: 26 January 2001 / Published online: 9 May 2001 相似文献
14.
Four-wave mixing of picosecond pulses in hollow fibers: expanding the possibilities of gas-phase analysis 总被引:2,自引:0,他引:2
A.B. Fedotov F. Giammanco A.N. Naumov P. Marsili A. Ruffini D.A. Sidorov-Biryukov A.M. Zheltikov 《Applied physics. B, Lasers and optics》2001,72(5):575-582
Third-harmonic, difference-frequency, and sum-frequency generation processes in hollow fibers are experimentally studied with
30-ps pulses having an energy of several millijoules. The experimental dependence of the difference-frequency signal on the
pressure of the gas filling the fiber agrees well with the results of calculations when the contribution of higher order waveguide
modes is taken into consideration, thus indicating the importance of nonlinear-optical processes involving higher order waveguide
modes of a hollow fiber. Hollow fibers are also shown to expand the possibilities of nonlinear-optical analysis of gases by
allowing the generation of third-harmonic and sum-frequency signals, which vanish in the regime of tight focusing in a medium
with normal dispersion.
Received: 26 September 2000 / Revised version: 15 January 2001 / Published online: 30 March 2001 相似文献
15.
Nonlinear optical and electrostatic force microscopy for ferroelectric polarization imaging 总被引:1,自引:0,他引:1
E.D. Mishina N.E. Sherstyuk K.A. Vorotilov A.S. Sigov R. Barberi M.P. Moret F. Manders M.P. De Santo P.K. Larsen T. Rasing 《Applied physics. B, Lasers and optics》2002,74(7-8):783-788
Second-harmonic generation (SHG)-based nonlinear optical microscopy is used for spatially resolved imaging of the polarization
switching in lead zirconium titanate ferroelectric thin films. The local SHG hysteresis loops reveal a strong dependence on
film composition and structure. The SHG microscopy results are in good agreement with the efficiency of electrostatic force
microscopy writing and allow us to predict the microscopic dielectric memory efficiency, both in contact and contact-less
ways.
Received: 15 January 2001 / Revised version: 27 March 2002 / Published online: 6 June 2002 相似文献
16.
K.-D. Zhu 《Applied physics. B, Lasers and optics》2001,72(3):349-353
The hysteresis behavior of a dense collection of two-level atoms embedded in a linear dielectric medium in an optical cavity
is investigated theoretically in terms of a parametric formulation method under the thin-sample approximation. The relation
of the output intensity to the input intensity is obtained in an explicit formula. The numerical results show that the hysteresis
behavior and the cavity transmission are different from those in vacuum because of the local-field enhancement and the local
cooperative decay effect.
Received: 27 June 2000 / Revised version: 11 September 2000 / Published online: 10 January 2001 相似文献
17.
The optical and non-linear optical properties of peripheral-substituted vanadium oxide phthalocyanine (VOPc) film and substituted
VOPc/polymer composite film were investigated using stationary and transient spectroscopy techniques. The absorption Q band
of the VOPc/polymer composite film shows a red shift relative to that of the peripheral-substituted VOPc film, revealing the
monomeric characteristics of VOPc molecules. Effective quenching of PL emission was observed for the VOPc/polymer composite
film and could be assigned to the efficient VOPc–polymer interaction. From pump-probe and optical Kerr effect (OKE) measurements,
two decay components were obtained by fitting the transients for both VOPc films. The fast component, in a femtosecond time
domain, originates from the electron–phonon interaction, and the difference in their slow decay is an indication of an efficient
ISC process in the VOPc/polymer composite film. The third-order non-linear optical susceptibilities of these films were determined
to be in the order of 10-11 esu.
Received: 25 October 2001 / Revised version: 8 January 2002 / Published online: 7 February 2002 相似文献
18.
The time evolution of the anti-Stokes signal produced from the non-linear interaction of a short Stokes pulse and two long
pump pulses that are nearly degenerate in frequency has been investigated. It is shown that this approach allows us to specify
the accuracy of CARS (coherent anti-Stokes Raman scattering) velocimetry and to extend the range of operation of the method.
In addition, an original optical scheme capable of delivering short visible pulses with good spatial and spectral properties
is reported. The optical bench has been used for the characterisation of a low-pressure laminar Mach-10 flow.
Received: 24 October 2001 / Revised version: 8 January 2002 / Published online: 14 March 2002 相似文献
19.
Thin films of polymer-based multi-layer conductive electrode to be used as a substrate for a plastic liquid crystal display
(LCD) have been prepared by a DC magnetron roll-to-roll sputtering method. The conductive layer is composed of three layers,
ITO/Ag/ITO or ITO/APC/ITO, where APC is Ag-Pd-Cu alloy, on the polymer substrate (Arton?), which has been treated with hard-coat
and gas-barrier layers. The properties of the conductive electrode for the plastic LCD were the following: (1) sheet resistance
is 6 Ω/square; (2) transparency is 88% at 550 nm; (3) H2O gas permeation through the plastics is 0.35 g/m2 in 24 h; (4) durability against solvents is good for 5% NaOH solution, IPA, methanol, NMP, acetone, etc.; (5) the irreversible
shrinkage and the compaction rate are both less than 3 ppm/h after annealing for 100 h at 150 °C.
Received: 22 January 2001 / Accepted: 30 January 2001 / Published online: 26 April 2001 相似文献
20.
B.V. Kamenev V.I. Emel’yanov E.A. Konstantinova P.K. Kashkarov V.Y. Timoshenko C. Chao V.K. Kudoyarova E.I. Terukov 《Applied physics. B, Lasers and optics》2002,74(2):151-154
Transients of the photoluminescence (1.54 μm) of Er3+ ions embedded in an amorphous silicon matrix excited with intensive laser pulses are simulated using a phenomenological model
which takes into account both the defect-related excitation mechanism and stimulated optical transitions in the ions. The
simulated transients are compared with the experimental ones observed in Er-doped amorphous silicon layers under pulsed laser
excitation. The modeling and the experimental results demonstrate a possibility to realize a regime of superradiance in the
system of Er3+ ions pumped via an electronic excitation of the amorphous matrix.
Received: 7 August 2001 / Revised version: 1 November 2001 / Published online: 17 January 2002 相似文献