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11.
Influence of Different Substrates on Laser Induced Damage Thresholds at 1064nm of Ta2O5 Films 下载免费PDF全文
Ta2O5 films are prepared on Si, BK7, fused silica, antireflection (AR) and high reflector (HR) substrates by electron beam evaporation method, respectively. Both the optical property and laser induced damage thresholds (LIDTs) at 1064 nm of Ta2O5 films on different substrates are investigated before and after annealing at 673 K for 12 h. It is shown that annealing increases the refractive index and decreases the extinction index, and improves the O/Ta ratio of the Ta2O5 films from 2.42 to 2.50. Moreover, the results show that the LIDTs of the Ta2O5 films are mainly correlated with three parameters: substrate property, substoichiometry defect in the films and impurity defect at the interface between the substrate and the films. Details of the laser induced damage models in different cases are discussed. 相似文献
12.
Indium-tin-oxide (ITO) films deposited on crystalline silicon wafer and Corning glass are prepared by directcurrent magnetron sputtering method at room temperature with various thicknesses. The thickness dependences of structure, resistance and optical refectance of ITO films are characterized. The results show that when the film thickness is less than 40 nm, the resistivity and optical reflectance of the ITO film changes remarkably with thickness. The optoelectrical properties trend to stabilize when the thickness is over 55 nm. The GXRD result implies that the ITO film begins to crystallize if only the thickness is large enough. 相似文献
13.
Microstructure and Optical Properties of AgxO Prepared by Direct-Current Magnetron-Sputtering Method 下载免费PDF全文
Two series of AgxO films are prepared on glass substrates by dc magnetron-sputtering method at room temperature and 90℃ under different oxygen to argon gas ratio (OAR) conditions. The mierostrueture is investigated by XRD and SEM in order to obtain the information on the component evolution of AgO+Ag2O to Ag2O. Its optical properties are investigated by reflectance and absorption spectroscopy to extract the information on metallic and dielectric behaviour evolution of Ag2O, AgO and silver particles and the interband transition. The results indicate that the AgxO film prepared at room temperature is mainly made up of AgO and Ag2 O clusters while Ag2O is the primary component of AgxO prepared at 90℃. The AgxO film mainly consisting of the primary component shows indirect interband transition structure occurring at 2.89eV. Combination of increasing OAR and substrate temperature is an effective method to lower the threshold of thermal decomposition temperature of AgxO and to deal with the bottleneck of short-wavelength optical and magneto-optieM storage. 相似文献
14.
K.-M. Källman M. Brenner V.Z. Goldberg T. Lönnroth P. Manngård A.E. Pakhomov V.V. Pankratov 《The European Physical Journal A - Hadrons and Nuclei》2003,16(2):159-169
The excitation function and angular distributions of elastic α-particle scattering on 28Si have been measured in the laboratory energy range 6-28 MeV using a backscattering technique on a thick target, yielding
a continuous energy distribution. More than 200 narrow states are observed, with widths in the range ∼ 30-100 keV at excitation
energies E
* = 13-32 MeV. Angular distributions at backward angles were measured, and angular momentum values of more than 83 states have
been deduced. The analysis gives spin-parities J
π, α-partial widths Γα and reduced widths of the narrow high-lying resonant states in 32S. The experimentally observed states display both the negative- and the positive-parity rotational-like sequences with seemingly
no parity splitting, a finding which is at variance with most potential-model predictions. The deduced effective moment of
inertia indicates a more extended structure than the ground-state configuration. The observed strength of each ℓ-value is
analyzed in terms of an underlying split doorway state of Lorentzian form, which yields an interpretation as fragmented rotational
α + 28Si states.
Received: 26 June 2000 / Accepted: 16 September 2002 / Published online: 4 February 2003
RID="a"
ID="a"e-mail: kkallman@abo.fi
RID="b"
ID="b"Present address: Swedish Polytechnic, FIN-65200 Vasa, Finland.
Communicated by D. Guerreau 相似文献
15.
Studies on CdS nanoparticles dispersed in silica matrix prepared by sol-gel technique 总被引:2,自引:0,他引:2
B. Bhattacharjee S.K. Bera D. Ganguli S. Chaudhuri A.K. Pal 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,31(1):3-9
SiO2/CdS-nanoparticle composite films (SiO2:CdS=85:15, 80:20, 75:25 and 70:30) were prepared by the sol-gel route. The films were characterized by studying microstructural
(XRD and TEM) and optical (transmittance and photoluminescence) properties. Band gaps of these films annealed at different
temperatures (373-473 K) for different times (10-120 min) indicated that the signature of nanocrystallinity is retained throughout
the range of our experimental conditions. A thermal diffusion process controlled growth in the crystallite size with increasing
annealing time and temperature. The average radii of the nanoparticles varied as the cube root of the annealing time but showed
exponential dependence on the inverse of annealing temperature. Photoluminescence (PL) studies of the composite films indicated
excitonic transitions. Theoretical analysis of the line shapes of the PL peaks recorded at 300 K and 80 K could be accounted
for by the combined effects of size distribution and phonon broadening. It was observed that the deformation potential (E
d) effectively controlled the line shapes of the PL measurements.
Received 24 May 2002 Published online 27 January 2003
RID="a"
ID="a"e-mail: msakp@mahendra.iacs.res.in 相似文献
16.
G. H. Ma J. Shen K. Rajiv S. H. Tang Z. J. Zhang Z. Y. Hua 《Applied physics. B, Lasers and optics》2005,80(3):359-363
One-dimensional photonic crystals with a defect layer of CdS were fabricated. The observed enhancement of two-photon absorption (TPA) in the CdS layer can be attributed to the intensified optical field confined within the defect layer of the photonic crystal. The results show that the enhancement of TPA coefficient depends basically on the number of periods of the photonic crystal and the defect mode position in the photonic band gap. The observation agrees qualitatively with the expectations of a computation by matrix transfer formulation. 相似文献
17.
We present a numerical model of Er3+–Tm3+–Pr3+-co-doped fiber amplifier pumped with 980 nm laser for the first time, to the best of our knowledge. The rate and power propagation
equations are solved numerically to analyze the effects of the pump power and active ion concentrations on the gains at 1310,
1470, 1530, 1600, 1650 nm windows. The results show that with pump power of 200 mW and when Pr3+, Tm3+, Er3+ concentrations are around 2.0×1024, 3.0×1024, 1.5×1024 (ions/m3), respectively, the signals at 1470, 1530, 1600 nm may be nearly equally amplified with gain of 11–12.0 dB in the active
fiber with length of 11.0 m, and the signals at 1310, 1470 and 1600 nm windows may be nearly equally amplified with gain of
12.0 dB in the active gain medium with length of 15.0 m. With pump power of 300 mW, the signals at 1470, 1530, 1600 nm may
be nearly equally amplified with a gain of 16.0 dB in the active medium with a length of 15.0 m. 相似文献
18.
D. S. L. Pontes E. Longo F. M. Pontes M. S. Galhiane L. S. Santos Marcelo A. Pereira-da-Silva J. H. D. da Silva A. J. Chiquito P. S. Pizani 《Applied Physics A: Materials Science & Processing》2009,96(3):731-740
Ferroelectric Pb1−x−y
Ca
x
Sr
y
TiO3 thin films (denoted by PCST90, PCST70, and PCST30) were deposited on the Pt/Ti/SiO2/Si substrates by a chemical solution deposition method. Their properties were investigated from the viewpoint of crystal
structure, microstructure, dielectric, and ferroelectric properties. X-ray diffraction patterns revealed the formation of
PCST90, PCST70, and PCST30 thin films without any secondary phases. Infrared and Raman spectroscopy results show that a gradual
phase transition from tetragonal to pseudocubic or cubic perovskite structure may occur in PCST thin films with the simultaneous
increase of Ca2+ and Sr2+ contents. Both substitution of isovalent Ca2+ and Sr2+ at Pb2+-site enhanced the dielectric constant and reduced the remnant polarization. In addition, ferroelectric test analyses show
that the PCST thin films undergo a ferroelectric-to-paraelectric phase transformation with an amount of Pb2+, Ca2+, and Sr2+ at 30%, 35%, and 35% mol, respectively. Hence, the absence of ferroelectric property may be attributed to a decreasing of
the octahedron distortion in the perovskite structure accompanied by a weakening of long-range ferroelectric order. 相似文献
19.
Two new modes of generating spiral pairs in an excitable medium have been found. They depend on a geometrical structure (GS) inside the medium. This may be formed e.g. as a result of scars or fibrosis in the heart tissue, or artificially built in a chemical reaction substrate. Both sources involve a GS composed of a circular “convergent lens” bounded by two opaque “walls”. One mode can be induced by a single wave and behaves as a “flip-flop” type of a limit cycle. The other mode is generated by a train of plane waves impinging on the GS, and is created at the focus of the converging wave-fragments. 相似文献
20.