共查询到20条相似文献,搜索用时 15 毫秒
1.
E. Nippolainen V.V. Prokofiev A.A. Kamshilin T. Jaaskelainen 《Applied physics. B, Lasers and optics》1999,69(1):45-50
We present an experimental study of the self-pumped phase-conjugate-mirror (SPPCM) recording in a Bi12TiO20 sample due to the partial internal reflection of the pump beam from the rear face. SPPCM has been recorded under an external
alternating electric field of a square-wave form with response time equal to 170 s at the pump beam intensity of 520 mW/cm2. The mechanism of the SPPCM formation is similar to that of photorefractive double-phase-conjugate mirrors. The most effective
SPPCM is recorded at the much larger pump-beam-incident angle than it could be supposed from the typical angular dependence
of the two-wave-mixing gain factor. Strong dependence of the gain distribution on the pump-beam-propagation angle is observed.
It is found that the response time strongly depends on the preliminary history of the sample.
Received: 11 August 1998 / Revised version: 14 January 1999 / Published online: 28 April 1999 相似文献
2.
M. Vasnetsov S. Lyuksyutov P. Buchhave P.E. Andersen P.M. Petersen 《Applied physics. B, Lasers and optics》1997,65(4-5):523-526
12 SiO20 crystals in the diffusion regime. We find unusually high cross-talk for two gratings with close spatial frequencies at wavelengths
488 and 476 nm. The results indicate that the density of free charge carriers does not directly follow light modulation at
low spatial frequencies.
Received: 2 December 1996/Revised version: 20 February 1997 相似文献
3.
J. Zelenka 《Czechoslovak Journal of Physics》1978,28(2):165-169
The elastic and piezoelectric constants and their temperature coefficients of bismuth germanium oxide have been determined. All of the elastic and piezoelectric constants were obtained from dynamic measurements of piezoelectrically driven narrow bars and thin plates at the temperature 22 °C. The temperature coefficients were measured on the same resonators in the temperature range from 16 °C to 70 °C. The thermal expansion measured in the temperature range from 50 °C to 200 °C is also given.The author wishes to acknowledge the help rendered by Professor Ing. Dr.Jaroslav Stank in connection with the measurement of the thermal expansion coefficient and by R.Trepera in the course of the preparation of the measured resonators. 相似文献
4.
We propose an experimental method for the determination of the electro-optic coefficients of photorefractive crystals. Using
anisotropic properties of the crystal and using the response of the crystal to different polarization states of the incident
light, it is possible to determine the ratio between various electro-optic coefficients by measuring the gain in a two-wave
mixing set-up. The accuracy of the measurements is estimated and the obtained electro-optic coefficients for a Ba0.77Ca0.23TiO3 crystal show good agreement with corresponding values already known from the literature.
Received: 24 January 2000 / Revised version: 23 May 2000 / Published online: 16 August 2000 相似文献
5.
4 (KTA) optical parametric oscillator (OPO) synchronously pumped by a cw diode-pumped mode-locked Nd:YVO4 oscillator–amplifier system. The laser system (pumped by 84 W of cw 808-nm diode radiation) generates 7-ps-long pulses at
1.064 μm with a repetition rate of 83.4 MHz and an average power of 29 W. The OPO, synchronously pumped by the 1.064-μm laser
pulses, consists of a 15-mm-long KTA crystal (cut for type II noncritical phase-matching) in a folded signal resonant linear
resonator. The average powers of the 1.54-μm signal radiation and the 3.47-μm idler radiation are 14.6 W and 6.4 W, respectively.
The total OPO output of 21 W corresponds to an internal efficiency of 75%. The experimental investigations include measurements
of the OPO output power (and its dependence on the pump power, the transmission of the output coupler, and the resonator length)
and of the pulse properties (such as pulse duration and spectral width). The measured results are in good agreement with the
predictions of a numerical analysis based on a split-step Fourier method.
Received: 4 May 1998 相似文献
6.
Dispersion of second-order nonlinear optical coefficient 总被引:2,自引:0,他引:2
J. Seres 《Applied physics. B, Lasers and optics》2001,73(7):705-709
A simple, approximate relation between the dispersion of the second-order nonlinear optical (SNLO) coefficient and first-order
susceptibility has been derived using the well-known results of density-matrix calculation of quantum-mechanical theory. A
new tensor of SNLO coefficient has been defined, which retains symmetries when the input beams are in the spectral range of
transparency while the generated beam can also be in the spectral range of absorption. The validity of the relation has been
checked for three ferroelectric crystals, KTP, LiNbO3 and KNbO3, which are transparent in the visible and near infrared, and for two semiconductors, GaP and GaAs, which absorb in the visible.
Contrary to Miller’s law, the presented relation is in good agreement with measurements.
Received: 8 February 2001 / Revised version: 2 July 2001 / Published online: 10 October 2001 相似文献
7.
3 O5 (LBO) crystal has been studied by using the bond valence theory of complex crystals. Chemical bond parameters and linear
and nonlinear optical (NLO) properties of each type of constituent chemical bonds are quantitatively determined. Because of
the different crystal structure characteristics of LBO from those of β-BaB2O4 (BBO), the two anionic groups, (B3O7)5- in LBO and (B3O6)3- in BBO, play different roles in contributions to their own total NLO tensor coefficients of LBO and BBO, respectively. By
comparison, we find that planar (B3O6)3- groups are the ideal structure model, leading to little cancellation of contributions of each kind of bond in these groups,
and this gives us a useful guide to design new NLO materials in the future.
Received: 24 January 1997/Accepted: 27 March 1997 相似文献
8.
The third-order optical nonlinearities in undoped and Fe-doped KTA crystals have been measured using the Z-scan technique
with femtosecond pulses at 780-nm wavelength. The nonlinear refractive index is determined to be 1.7×10−15 cm2/W and 0,9×10−15 cm2/W for undoped and Fe-doped KTA, respectively. No two-photon absorption occurs in these crystals. It is shown that doping
with Fe2O3 could weaken refractive nonlinearity of KTA, suggesting that Fe:KTA will improve the performance of KTA in high-intensity
femtosecond laser applications. In addition, the measured nonlinear index of refraction in KTA crystals is about five times
lower than that predicted by the two-band theory. One of the reasons for the discrepancy is given as the applicable limit
of the simple theory in which a two-parabolic band model has been assumed in the analysis.
Received: 3 June 1999 / Published online: 20 October 1999 相似文献
9.
An optical power limiter is a self-actuating nonlinear optical device that transmits low-intensity light and blocks high-intensity light. A light-controlled electro-optic power limiter that uses a Bi(12)SiO(20) crystal has been demonstrated. The threshold light intensity is determined by the control light and can be set to any desired level. The response time of the light-controlled electro-optic power limiter is of the order of 1 ms. 相似文献
10.
Photorefractive waveguides in oxide crystals: fabrication, properties, and applications 总被引:2,自引:0,他引:2
D. Kip 《Applied physics. B, Lasers and optics》1998,67(2):131-150
3 , LiTaO3, BaTiO3, KNbO3, SrxBa1-xNb2O6 (0.25≤x≤0.75, SBN), and Bi12(Si,Ti,Ge)O20 (BSO, BTO, BGO) waveguides are discussed. Furthermore, the suitability of photorefractive waveguides for nonlinear optical
components is demonstrated in some examples.
Received: 21 April 1998/Revised version: 28 May 1998 相似文献
11.
Z. Bryknar I.P. Bykov M.D. Glinchuk V.V. Laguta Y.L. Maximenko Z. Potuček L. Jastrabík H.-J. Schulz 《Applied Physics A: Materials Science & Processing》1998,66(5):555-559
2+ spectra in axial and cubic crystal fields. Cu2+ substitutes for Ti4+ and the excess charge can be compensated by La3+ on a nearest-neighbor site, thus creating axial symmetry. The centers of cubic symmetry are those where the charge is compensated
in distant spheres.
In contrast to pure PLZT, PLZT:Cu exhibits a new luminescence band peaking at 1.18 eV. This emission is ascribed to the 2T2(D)→2E(D) transition of Cu2+(3d9) which can be excited either in the resonant 1.87 eV band or via charge-transfer excitation bands at 2.40, 2.57, and 3.03 eV.
The absorption band at 1.45 eV is assumed to be that of Cu+ ions. Annealing in hydrogen and in oxygen atmospheres caused decrease and restoration, respectively, of the ESR and luminescence
intensities as a consequence of Cu2+ conversion into Cu1+ and vice versa.
Received: 14 November 1997/Accepted: 8 December 1997 相似文献
12.
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
13.
The heat produced in conjunction with the processes of stimulated Raman scattering and four-wave Raman mixing in hydrogen
was measured by photothermal refraction spectroscopy. Many vibrational, rotational, and vibrationally shifted rotational Raman
lines are exclusively/simultaneously generated by changing the polarization of the laser beam and the hydrogen pressure. Thermal
loss occurs predominantly from vibrational Raman scattering, which can be ascribed to a large Raman shift frequency of 4155 cm-1 for the vibrational transition. In contrast to stimulated Raman scattering, little or no thermal loss is observable during
the process of four-wave Raman mixing.
Received: 12 April 1999 / Revised version: 12 July 1999 / Published online: 20 October 1999 相似文献
14.
D.G. Papazoglou N.C. Deliolanis A.G. Apostolidis E.D. Vanidhis 《Applied physics. B, Lasers and optics》2000,71(6):841-848
We study the diffraction efficiency of volume phase gratings in Bi12GeO20, when the grating vector, lying on a (111) plane, is at an angle with respect to the crystallographic direction. An external
bias field parallel to the direction is applied during recording, thus, the recording conditions depend on the grating vector
orientation. The basic parameters determining the diffraction efficiency are the grating vector orientation, the rotatory
power and the field-induced linear birefringence (primary and secondary). Analytic expressions for the diffraction efficiency
have been obtained by taking into account all the above-mentioned parameters, provided that linearly polarized light is incident
on the crystal. In this configuration, the influence of the secondary electro-optic effect (inverse piezoelectric and photoelastic
effects) to the diffraction efficiency is actually stronger than the influence of the primary effect. Experimental results
are given.
Received: 3 January 2000 / Revised version: 6 June 2000 / Published online: 13 September 2000 相似文献
15.
Pulse compression of nanojoule pulses in the visible using microstructure optical fiber and dispersion compensation 总被引:2,自引:0,他引:2
S. Lakó J. Seres P. Apai J. Balázs R.S. Windeler R. Szipőcs 《Applied physics. B, Lasers and optics》2003,76(3):267-275
Experimental results on the pulse compression of 1-nJ, 150-fs pulses from a tunable, 76-MHz Ti:sapphire laser oscillator operating
at around 750 nm are reported. The length of the pulses can be compressed to nearly one tenth by applying a high-delta, single-mode
microstructured optical fiber exhibiting zero group-delay dispersion at 767 nm, and by a prism-pair/chirped-mirror compressor.
The experimental results are verified by theoretical investigations modeling the pulse propagation taking into account non-linear
self-phase modulation and fiber dispersion.
Received: 10 June 2002 / Revised version: 15 November 2002 / Published online: 12 February 2003
RID="*"
ID="*"Corresponding author. Fax: +36-1/375-4553, E-mail: szipoecs@sunserv.kfki.hu 相似文献
16.
Received: 20 June 1997/Revised version: 26 January 1998 相似文献
17.
U. Griebner R.A. Kaindl T. Elsaesser W. Seeber 《Applied physics. B, Lasers and optics》1998,67(6):757-760
Received: 29 September 1998 相似文献
18.
P.S. Parkinson D. Lim R. Büngener J.G. Ekerdt M.C. Downer 《Applied physics. B, Lasers and optics》1999,68(3):641-648
0.9 Ge0.1(001)/Si(001) films with SH photon energies 3.1<2hν<3.5 eV near the bulk E1 critical point of Si(001) or Si0.9Ge0.1(001). Ge was deposited on Si(001) by using atomic layer epitaxy cycles with GeH4 or Ge2H6 deposition at 410 K followed by hydrogen desorption. As Ge coverage increased from 0 to 2 monolayers the SH signal increased
uniformly by a factor of seven with no detectable shift in the silicon E1 resonant peak position. SH signals from Si0.9Ge0.1(001)/Si(001) were also stronger than those from intrinsic Si(001). Hydrogen termination of the Si0.9Ge0.1(001) and Ge/Si(001) surfaces strongly quenched the SH signals, which is similar to the reported trend on H/Si(001). We attribute
the stronger signals from Ge-containingsurfaces to the stronger SH polarizability of asymmetric Ge-Si and Ge-Ge dimers compared
to Si-Si dimers. Hydrogen termination symmetrizes all dimers, thus quenching the SH polarizability of all of the surfaces
investigated.
Received: 13 October 1998 / Revised version: 18 January 1999 相似文献
19.
N. Erdmann V. Sebastian V.N. Fedoseyev M. Hannawald G. Huber T. Kautzsch K.-L. Kratz V.I. Mishin M. Nunnemann G. Passler N. Trautmann 《Applied physics. B, Lasers and optics》1998,66(4):431-433
1 =228.8 nm). Laser light with an average power of 2 mW was obtained after frequency tripling and was successfully used for
RIS test measurements on cadmium with a time-of-flight mass spectrometer. The eight stable Cd isotopes could be identified
unambiguously.
Received: 6 October 1997 相似文献
20.
We report a simplified Z-scan technique based on a study on the symmetric features of a typical Z-scan curve. The contributions
from the two-photon absorption (TPA) and the nonlinear refraction (NLR) are easily separated from a closed-aperture Z-scan
curve using this method. And the determination of the two nonlinearities is simplified and unambiguous. We demonstrate this
method on ZnSe, CdS, and ZnTe semiconductors with 120-fs laser pulses. And the influence from the uncertainty of the focal
plane (Z=0) position is discussed. It is also found that the TPA coefficient can be obtained independently without knowing
the exact location of the focal point.
Received: 8 July 1999 / Published online: 3 November 1999 相似文献