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1.
I. V. Kedyk P. Mathey G. Gadret A. A. Grabar K. V. Fedyo I. M. Stoika I. P. Prits Y. M. Vysochanskii 《Applied physics. B, Lasers and optics》2008,92(4):549-554
In this work we report results on electro-physical, optical and photorefractive investigations for Sb-doped Sn2P2S6 crystals. The crystals are obtained by two methods: the vapour-transport technique and the Bridgman technique using stoichiometric
Sn2P2S6 composition with different amounts of antimony in the initial compound. The good optical quality of the crystals obtained
with the Bridgman technique is underlined. The dependences of the photorefractive two-beam coupling coefficient and the grating
build-up time are investigated at the wavelength of 633 nm. It is found that the sample doped with 1.5% of Sb is characterized
by an optimal combination of the main photorefractive parameters exhibiting a fairly high two-beam coupling coefficient (up
to 20 cm−1) and a short response time (1.3 ms) that is the shortest among all the previously studied Sn2P2S6 crystals in the red spectral region. 相似文献
2.
T. P. J. Han E. Cantelar G. Lifante F. Cusso F. Jaque 《Applied physics. B, Lasers and optics》2009,94(2):209-214
This paper reports on the spectroscopy properties, absorption and luminescence, of Cr3+ ions in singly doped, ZnO-codoped, and Zn in-diffused LiNbO3:Cr crystals. In addition to the broad absorption, inter-ionic transitions ascribed to Cr3+ ions located in Li+ and Nb5+ sites; [Cr]Li and [Cr]Nb centres two absorption bands at higher energy are reported and ascribed to the charge transfer transitions of the Cr3+ ions of the two defect centres.
The charge transfer transitions are used as optical probe to study the role of the Zn ions in the Zn in-diffused LiNbO3:Cr samples. It has been observed that the Zn-in-diffused processes created [Cr]Nb centres in the diffusion zone. The location of the diffused Zn2+ ions is considered to be in Li+ site, displacing the Cr3+ ions from the Li+ sites, [Cr]Li, to the Nb5+ positions, [Cr]Nb. 相似文献
3.
High-resolution photorefractive gratings in nematic liquid crystals sandwiched with photoconductive polymer film 总被引:1,自引:1,他引:0
F. Yao Y. Pei Yu Zhang J. Zhang C. Hou X. Sun 《Applied physics. B, Lasers and optics》2008,92(4):573-576
Photorefractive gratings with high grating resolution were observed in the 20 μm thick low-molar-mass nematic liquid crystal
(NLC) cell with a separate photoconductive (PC) poly(N-vinylcarbazole) layer. An orientational grating with a grating spacing of 1.9 μm was produced. It is believed that a space–charge
field with small fringe spacing forms in the PC layer and its evanescent component penetrates into the NLC layer. The penetrated
evanescent field drives the NLC to reorient, and consequently the orientational grating forms. The model indicates that the
modulated field exists in several hundred nanometers near the surface, and thus the orientational grating is not full of the
NLC film, which is consistent with the observed phenomena of the multiple diffractions. Besides, asymmetric two-beam coupling
of 11.2% was achieved for the grating with a grating spacing of 1.9 μm, and a net gain coefficient of larger than 62 cm−1 was obtained. 相似文献
4.
L. Kovács M. Mazzera E. Beregi R. Capelletti 《Applied physics. B, Lasers and optics》2009,94(2):273-277
Several weak absorption bands have been observed in the optical absorption spectra of pure and rare-earth-doped YAl3(BO3)4 single crystals in the 3350– 3650 cm−1 wave number region. Two of them, peaking at about 3377 cm−1 and 3580 cm−1 in the 8 K spectra, appear in most of the samples. They are tentatively attributed to the stretching mode of OH− ions incorporated in the crystal during the growth. An additional absorption band at about 5250 cm−1 at 8 K has also been detected in almost all samples. The temperature and polarization dependences of these bands, and their
possible origin, are discussed. 相似文献
5.
The absorption spectra, fluorescence spectrum and fluorescence decay curve of Nd3+ ions in CaNb2O6 crystal were measured at room temperature. The peak absorption cross section was calculated to be 6.202×10−20 cm2 with a broad FWHM of 7 nm at 808 nm for E//a light polarization. The spectroscopic parameters of Nd3+ ions in CaNb2O6 crystal have been investigated based on Judd-Ofelt theory. The parameters of the line strengths Ω
t
are Ω
2=5.321×10−20 cm2,Ω
4=1.734×10−20 cm2,Ω
6=2.889×10−20 cm2. The radiative lifetime, the fluorescence lifetime and the quantum efficiency are 167 μs, 152 μs and 91%, respectively. The fluorescence branch ratios are calculated to be β
1=36.03%,β
2=52.29%,β
3=11.15%,β
4=0.533%. The emission cross section at 1062 nm is 9.87×10−20 cm2. 相似文献
6.
J.?Villarroel M.?Carrascosa A.?García-Caba?es O.?Caballero-Calero M.?Crespillo J.?Olivares 《Applied physics. B, Lasers and optics》2009,95(3):429-433
The photorefractive behaviour of a novel type of optical waveguides fabricated in LiNbO3 by swift heavy ion irradiation is investigated. First, the electro-optic coefficient r
33 of these guides that is crucial in the photorefractive effect is measured. Second, two complementary aspects of the photorefractive
response are studied: (i) recording and light-induced and dark erasure of holographic gratings; (ii) optical beam degradation
in single-beam configuration. The main photorefractive parameters, recording and erasing time constants, maximum refractive-index
change and optical damage thresholds are determined. 相似文献
7.
We investigate non-volatile holographic data storage in photorefractive lithium niobate crystals. Infrared picosecond laser
pulses are used to write holograms after sensitizing the crystal with blue light from a cw-laser. The dependence of the dynamic
range and the photoconductivity on the pulse intensities and the recording wavelength is investigated in detail. The results
can be explained by a two-center model if the mean intensity of the laser pulses is considered. We demonstrate that several
fixed holograms can be multiplexed by employing the wavelength multiplexing technique. 相似文献
8.
D. Nau A. Christ H. Giessen A. Wagner A. Euteneuer M. Salvador E. Mecher K. Meerholz 《Applied physics. B, Lasers and optics》2009,95(1):31-35
Photorefractive polymers allow to reversibly record holograms over a broad spectral range. This capability offers the possibility
to store the information contained in ultrafast optical pulses (i.e., time domain) in the frequency domain. We demonstrate
a storage bandwidth of >80 nm around 800 nm (i.e., >36 THz), giving a temporal resolution for Gaussian pulses of 13 fs at
room temperature. Time reversal of a pulse train of 130 fs pulses confirms these capabilities. 相似文献
9.
N. Coluccelli G. Galzerano L. Bonelli A. Toncelli A. Di Lieto M. Tonelli P. Laporta 《Applied physics. B, Lasers and optics》2008,92(4):519-523
We present a comparative analysis on the growth, the spectroscopic features, and the cw laser action of room-temperature Yb(5%):LiYF4 (YLF) and Yb(10%):KYF4 (KYF) crystals. Optical slope efficiencies of 33% and 52% have been demonstrated for Yb:YLF and Yb:KYF crystals, respectively.
A remarkable wide wavelength tunability from 1.01 to 1.07 μm has been obtained for both laser crystals. 相似文献
10.
S. Vatnik M. C. Pujol J. J. Carvajal X. Mateos M. Aguiló F. Díaz V. Petrov 《Applied physics. B, Lasers and optics》2009,95(4):653-656
The three thermo-optic coefficients of the biaxial laser host KLu(WO4)2 are measured at 633 nm by a deflection method. Their values at 300 K amount to ∂
n
g
/∂
T=−7.4×10−6 K−1; ∂
n
m
/∂
T=−1.6×10−6 K−1 and ∂
n
p
/∂
T=−10.8×10−6 K−1. Nearly athermal propagation directions are found for polarizations along the N
m
and N
p
dielectric axes. 相似文献
11.
O.?Caballero-Calero A.?García-Caba?es M.?Carrascosa F.?Agulló-López J.?Villarroel M.?Crespillo J.?Olivares 《Applied physics. B, Lasers and optics》2009,95(3):435-439
The generation of periodically poled structures in waveguides prepared by swift-heavy-ion (SHI) irradiation, i.e. in the electronic
stopping power regime, has been achieved following two different strategies. In one of them we have prepared bulk PPLN samples
by an applied electrical field, followed by irradiation with F ions at 22 MeV. After the ion irradiation, a waveguide showing
a high optical confinement is obtained, preserving the original PPLN structure. The second strategy consisted of electric
periodic poling of previously fabricated swift-ion-irradiated waveguides. To our knowledge this method has not been, so far,
successful for conventional implanted waveguides. The successful fabrication of PPLN structures on novel waveguides prepared
by SHI irradiation offers a promising potential for nonlinear integrated optical devices. 相似文献
12.
S. M. Kostritskii 《Applied physics. B, Lasers and optics》2009,95(3):421-428
Original results on investigation of the photorefractive effect in straight channels and integrated-optical circuits such
as a directional coupler, Y-splitter and Mach–Zehnder interferometer, exploiting titanium-indiffused and proton-exchanged
LiNbO3 waveguides, are presented. It has been found that the photorefractive damage is non-negligible for IR radiation with wavelengths
near 1.5 μm in all circuits studied. The new methods for accurate evaluation of small extents of photorefractive effect are
proposed. 相似文献
13.
M. Lancry N. Groothoff B. Poumellec J. Canning 《Applied physics. B, Lasers and optics》2009,94(4):589-597
The growth rate of Bragg gratings written using 193-nm light from an ArF excimer laser is shown to be non-linear with the
pulse energy density for Er3+ co-doped Al silica. This yields a refractive-index increase up to a few 10−3. We then use phase-shift interferometry to measure the sample surface topography following exposure. Subsequently, we formulate
an inhomogeneous stress model to analyse the observed change of volume within the core material. Below pulse energies of 550
mJ/cm2, the results show that refractive-index changes are primarily due to a densification process. At higher pulse energies material
re-expansion occurs. 相似文献
14.
Tingyin Ning Cong Chen Yueliang Zhou Heng Lu Dongxiang Zhang Hai Ming Guozhen Yang 《Applied Physics A: Materials Science & Processing》2009,94(3):567-570
CaCu3Ti4O12 (CCTO) thin films were successfully prepared on LaAlO3 substrates by pulsed laser deposition technique. We measured the nonlinear optical susceptibility of the thin films using
Z-scan method at a wavelength of 532 nm with pulse durations of 25 ps and 7 ns. The large values of the third-order nonlinear
optical susceptibility, χ
(3), of the CCTO film were obtained to be 2.79×10−8 esu and 3.30×10−6 esu in picosecond and nanosecond time regimes, respectively, which are among the best results of some representative nonlinear
optical materials. The origin of optical nonlinearity of CCTO films was discussed. The results indicate that the CCTO films
on LaAlO3 substrates are promising candidate materials for applications in nonlinear optical devices. 相似文献
15.
S. Rivier U. Griebner V. Petrov H. Zhang J. Li J. Wang J. Liu 《Applied physics. B, Lasers and optics》2008,93(4):753-757
Passive mode locking of the self-frequency doubling Yb:YAB crystal with a saturable absorber mirror is studied at the fundamental
wavelength. This laser has a very low threshold, and pulses as short as 85 and 87 fs are obtained for Ti:sapphire and diode
laser pumping, respectively. 相似文献
16.
E.??liwińska S.?Mansurova U.?Hartwig K.?Buse K.?Meerholz 《Applied physics. B, Lasers and optics》2009,95(3):519-524
A new class of photo-refractive (PR) composite materials based on poly(N-vinylcarbazole) (PVK) (co-)sensitized with nano-crystalline lithium niobate (LiNbO3) is presented. The steady-state performance, as well as the kinetics of the photo-refractive grating formation, was investigated
by degenerate four-wave mixing (DFWM) and two-beam-coupling (TBC) experiments. We found an optimum content of LiNbO3 nano-particles of only 10−3 wt.%. Even at concentrations as low as 10−7 wt.% a notable effect of the nano-crystals was detected. This yields materials with improved PR performance compared to that
of the standard PR polymer material sensitized by TNF only. The role of LiNbO3 nano-particles is discussed in detail: The particles support generation and transport of the free-charge carriers. Furthermore,
they increase the electron trap density. 相似文献
17.
M. Takeguchi M. Shimojo K. Furuya 《Applied Physics A: Materials Science & Processing》2008,93(2):439-442
Electron beam induced deposition was performed using a Pt(PF3)4 precursor gas. Self-standing nanowires were produced on the edge of a molybdenum film, followed by two post-deposition processes;
electron beam irradiation at room temperature and heating at about 400 K in vacuum. The as-deposited nanowires were composed
of an amorphous phase, of which the dominant composition was platinum but containing a small amount of phosphorus impurity.
After irradiating with a 300 keV electron beam, the amorphous nanowires were transformed to crystalline ones. By heating,
the as-deposited nanowires became single-crystal platinum with a large grain size and the phosphorus content disappeared. 相似文献
18.
V. K. Rai 《Applied physics. B, Lasers and optics》2009,95(2):329-333
Upconversion luminescence in triply ionized praseodymium-doped TeO2–Li2O glass using excitation at ∼590 nm into the 1D2 level from a dye laser pumped with the second harmonic of a pulsed Nd:YAG laser has been reported. The mechanism involved
in the upconversion emission observed at ∼480 nm indicates that the most important contribution is energy transfer among praseodymium
ions in pairs followed by the dipole–dipole interaction. The rate-equation model for the emission at ∼480 nm that provides
direct information to determine the energy-transfer rates containing the pair of states involved in the upconversion process
has been explored. 相似文献
19.
F. Guo J. Ru H. Li N. Zhuang B. Zhao J. Chen 《Applied physics. B, Lasers and optics》2009,94(3):437-441
Lithium terbium molybdate (LiTb(MoO4)2) single crystal was grown by the Czochralski method. The lattice parameters of the crystal were determined by X-ray diffraction
analysis. The absorption coefficient and the Faraday rotation spectrum (B=1.07 T) were investigated at wavelengths of 400–1500 nm at room temperature. Verdet constants of LiTb(MoO4)2 crystal at 532-, 633- and 1064-nm wavelengths were measured by the extinction method. The results show that LiTb(MoO4)2 crystal has a larger magneto-optical figure of merit than that of terbium gallium garnet at wavelengths of 600–1500 nm. 相似文献
20.
Ye. P. Shershakov Yu. V. Miklyaev B. Ya. Zel'dovich 《Applied Physics A: Materials Science & Processing》1994,59(6):575-578
The saturation of the fundamental harmonic of the space-charge field is investigated experimentally in dependence of the contrast m and the amplitude of an external ac and dc field in a BTO crystal with a large electron-drift length. The behaviour of the first harmonic is explained qualitatively with the aid of perturbative analysis. 相似文献