共查询到20条相似文献,搜索用时 31 毫秒
1.
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
2.
B.I. Sturman A.S. Gorkunova K.H. Ringhofer 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,23(2):291-297
We investigate analytically and numerically the influence of the type of the photorefractive nonlinear response on the periodic
states (attractors) which occur during feedback controlled 2W-coupling and correspond to almost 100% diffraction efficiency
of the dynamic index grating. In addition to the case of the local response typical, for example, for LiNbO3 crystals we consider the cases of nonlocal (diffusive) response (BaTiO3, SBN) and resonant response (DC-biased BSO, BTO, and BGO crystals). It is shown that the conditions for the transition to
the periodic states and their apparent characteristics are strongly different for the two limiting cases above.
Received 16 July 2002 / Received in final form 29 October 2002 Published online 4 March 2003 相似文献
3.
A. Thompson N. Nazhestkina A. Siahmakoun G. Duree N. Roesler 《Applied physics. B, Lasers and optics》2003,76(5):547-554
We present experimental investigations of electrical fixing techniques in Ce:SBN:60. The effect of crystal fatigue on the
diffraction efficiency of electrically fixed photorefractive gratings is studied. We observed that applying an ac field to
the crystal eliminated crystal fatigue and improved diffraction efficiency. A controllable diffraction efficiency of a photorefractive
grating is presented. A reproducible diffraction efficiency of up to 75% is obtained using a write-reveal grating technique
with high-voltage pulses of opposite polarity. We also show that the diffraction efficiency can be controlled by varying the
intensity of the writing beams incident to the crystal during the recording process. A method of determining the hysteresis
loop using the domain-fixing technique is proposed. The dependence of the diffraction efficiency on the direction of the applied
electric field while writing the hologram is studied. Our experiments show that, during writing, when the electric field is
applied opposite to the c axis the grating can be successfully revealed with both positive and negative dc voltages. However,
when the grating is written with a field parallel to the c axis, the grating can be revealed only with a field applied in
the opposite direction.
Received: 28 October 2002 / Revised version: 28 February 2003 / Published online: 14 May 2003
RID="*"
ID="*"Corresponding author. Fax: +1-812/872-6167, E-mail: azad.siahmakoun@rose-hulman.edu 相似文献
4.
Laser operation of the new stoichiometric crystal KYb(WO4)2 总被引:8,自引:0,他引:8
P. Klopp U. Griebner V. Petrov X. Mateos M.A. Bursukova M.C. Pujol R. Sole J. Gavalda M. Aguilo F. Güell J. Massons T. Kirilov F. Diaz 《Applied physics. B, Lasers and optics》2002,74(2):185-189
We demonstrate for the first time laser operation with the monoclinic stoichiometric crystal KYb(WO4)2 (hereafter KYbW). Lasing on the 2
F
5/2
?2
F
7/2
transition of Yb3+ at room temperature has been achieved near 1074 nm with >41% slope efficiency (>26% maximum conversion efficiency) using
a 0.5-mm-thick plate of KYbW. This new laser material holds great promise for diode-pumped high-power lasers, thin-disk and
waveguide designs as well as for ultrashort (ps/fs) pulse laser systems.
Received: 10 October 2001 / Revised version: 19 November 2001 / Published online: 17 January 2002 相似文献
5.
Heyuan Guan Yunxia Jin Shijie Liu Fanyu Kong Yin Du Kai He Kui Yi Jianda Shao 《Applied physics. B, Lasers and optics》2014,114(4):557-565
Metal multi-layer dielectric gratings (MMDG) for pulse compressors in high-energy laser systems should provide broad bandwidth as well as high laser-induced damage thresholds. The non-uniform optical near-field distribution of MMDG is an important factor that limits damage resistant capabilities. MMDG for pulse compressors operating at 800 nm with a corrugated SiO2 layer are designed by using a genetic algorithm and the Fourier mode method. The diffraction efficiency, bandwidth, and near-field distribution of the MMDG are theoretically investigated. For the single dielectric match layer grating, the bandwidth is 140 nm, if the thickness and refractive index of the match layer are changed, the maximum electric field in the grating ridge, match layer, and metal layer of the grating increases with the decrease in grating diffraction efficiency. For the multi-dielectric match layer grating, the bandwidth and the maximum electric field in the metal layer decrease with the increase in high- and low-index material pairs, and the maximum electric field in the grating ridge and match layer initially decreases and then increases. Over a wide wavelength range, the maximum electric field in the grating ridge, match layer, and metal layer is minimal near the central wavelength. Moreover, MMDG should be used at larger incident angles while keeping enough bandwidth to reduce the electric field in the grating. 相似文献
6.
Cavity ring-down spectroscopy is a relatively new and quite sensitive technique for the measurement of gas-phase optical extinction.
It holds the potential for simple, direct and sensitive measurement of the concentrations of a variety of trace gases in the
atmosphere. For example, detection of the nitrate radical, NO3, and its companion, dinitrogen pentoxide, N2O5, has been demonstrated with a sensitivity of 0.25 pptv (1σ). This paper considers several of the requirements for the application
of cavity ring-down spectroscopy to concentration measurements of trace gases in ambient air. These include detection sensitivity,
measurement of an accurate zero in the presence of competing absorbers, cavity stability and mirror cleanliness, laser line-width
effects, saturation effects, Rayleigh scattering, the influence of atmospheric aerosols and sampling issues for reactive species.
Examples drawn from our work on NO3 and N2O5 detection in the field illustrate these considerations.
Received: 1 April 2002 / Revised version: 5 June 2002 / Published online: 12 September 2002
RID="*"
ID="*"Corresponding author. Fax: +1-303/497-5822, E-mail: sbrown@al.noaa.gov 相似文献
7.
A. Shumelyuk D. Barilov S. Odoulov E. Krätzig 《Applied physics. B, Lasers and optics》2003,76(4):417-421
We apply, for the first time to our knowledge, photorefractive grating spectroscopy to obtain not-yet-known data on the anisotropy
of the dielectric permittivity of Sn2P2S6. Two independent techniques are used, one based on measurements of the amplitude of the space-charge field grating as a function
of grating spacing and the other based on measurements of the grating decay time, also as a function of grating spacing. Both
techniques provide close values for the anisotropy, which appears to be well pronounced, a ratio εxx/εzz≈4 is revealed for two of the three independent components of the dielectric tensor. Our data also allow us to conclude that
the charge mobility is nearly isotropic in the same plane, μxx/μzz≈1.
Received: 2 December 2002 / Published online: 26 March 2003
RID="*"
ID="*"Corresponding author. Fax: +380-44/265-2359, E-mail: odoulov@iop.kiev.ua 相似文献
8.
Design of High-Efficiency Diffraction Gratings Based on Rigorous Coupled-Wave Analysis for 800nm Wavelength 下载免费PDF全文
We report on the design of a high diffraction efficiency multi-layer dielectric grating with wide incident angle and broad bandwidth for 80Ohm. The optimized grating can achieve 〉 95% diffraction efficiency in the first order at an incident angle of 5° from Littrow and a wavelength from 77Ohm to 83Ohm, with peak diffraction efieieney of 〉 99.5% at 80Ohm. The electric field distribution of the optimized multi-layer dielectric grating within the gratings ridge is 1.3 times enhancement of the incidence light, which presents potential high laser resistance ability. Because of its high-effieieney, wide incident, broad bandwidth and potential high resistance ability, the multi-layer dielectric grating should have practical application in Ti:sapphire laser systems. 相似文献
9.
N.I. Nazhestkina A.A. Kamshilin O.V. Kobozev V.V. Prokofiev T. Jääskeläinen 《Applied physics. B, Lasers and optics》2001,72(6):767-773
Two-wave mixing of phase-modulated beams in photorefractive crystals under a dc electric field is studied both theoretically
and experimentally. Based on the vectorial theory of light diffraction in crystals of cubic symmetry, we derived an analytical
expression that describes the phase demodulation in crystals with an arbitrarily oriented electric field. The phase-demodulation
technique was used for estimation of the space-charge field created in photorefractive crystals. It is shown that the space-charge-field
grating created in GaP and Bi12TiO20 crystals is much smaller than that predicted from the one-level band-transport model of the photorefractive effect.
Received: 12 December 2000 / Revised version: 8 February 2001 / Published online: 27 April 2001 相似文献
10.
S. Mendricks X. Yue R. Pankrath H. Hesse D. Kip 《Applied physics. B, Lasers and optics》1999,68(5):887-891
During holographic recording in lead germanate (Pb5Ge3O11) crystals two types of refractive-index gratings are observed. One has a very fast response whereas the second builds up
comparably slowly. Measurements of diffraction efficiency and two-beam coupling are carried out to study the formation of
both gratings and to obtain the relative phase between them. Differently doped and thermally treated samples are divided into
four classes due to their different time evolution of diffraction efficiency and of the energy transfer direction during two-beam
coupling. The classification depends on doping and treatment. For Ni-doped and thermally treated samples dark and photo conductivities
corresponding to the slow grating are determined, indicating that Ni-doping combined with oxidation enhances the properties
of the slow grating.
Received: 18 November 1998 / Published online: 7 April 1999 相似文献
11.
Volume phase-hologram formation by the photorefractive effect in KNbO3 is accompanied by a stationary energy transfer between writing beams. The change in energy transfer by applying an electric
field on the reduced crystals is shown to be due to an efficient increase in migration length which can reach values comparable
or larger than the fringe spacing. It is demonstrated that photovoltaic contribution to the diffraction efficiency and energy
transfer is rather small in reduced KNbO3 and that diffusion of photogenerated free holes is the dominant charge transport for the photorefractive effect in unbiased
crystals. The experimental results for diffraction efficiency and energy transfer as a function of grating spacing, electric
field, light intensity and temperature is well described by a recent theory of Kukhtarev and Vinetskii. 相似文献
12.
E.B. Lopes H. Alves E. Ribera M. Mas-Torrent P. Auban-Senzier E. Canadell R.T. Henriques M. Almeida E. Molins J. Veciana C. Rovira D. Jérome 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,29(1):27-33
This article reports the investigation of a new low-dimensional organic salt, (TTDM-TTF)2 [Au(mnt)2], by single crystal X-ray diffraction, static magnetic susceptibility, EPR, thermopower, electrical resistivity measurements
under pressure up to 25 kbar and band structure calculations. The crystal structure consists in a dimerized head to tail stacking
of TTDM-TTF molecules separated by layers of orthogonal Au(mnt)2 anions. The absence of overlap between neighboring chains coming from this particular crystal structure leads to an extreme
one-dimensionality (1-D) for which the carriers of the half-filled conduction band become strongly localized in a Mott-Hubbard
insulating state. This material is the first 1-D conductor in which the Mott-Hubbard insulating character cannot be suppressed
under pressure.
Received 15 April 2002 / Received in final form 17 June 2002 Published online 17 September 2002 相似文献
13.
J. Kodymová O. Špalek V. Jirásek M. Čenský G.D. Hager 《Applied Physics A: Materials Science & Processing》2003,77(2):331-336
This article addresses the development of a Chemical Oxygen-Iodine Laser (COIL) with alternative chemical ways of generating
atomic iodine. Injection of atomic iodine as opposed to molecular iodine has the potential to improve the COIL efficiency.
This paper describes two chemical methods for generating iodine atoms based on the gas phase reactions of hydrogen/deuterium
iodide with fluorine or chlorine atoms, which are also produced chemically. Simplified one-dimensional gas dynamic modeling
that describes the stream-wise profiles of species concentrations within both reaction systems is used to gain a theoretical
understanding of both reaction systems under COIL conditions. The modeling results are used for the design of an experimental
device and the interpretation of experimental data. The first experimental investigation studies the production of iodine
atoms produced from reactions of Cl with HI. Atomic iodine yields of 70–100% in nitrogen are obtained, and the gain on the
I(2
P
1/2)–I(2
P
3/2) transition in a flow of singlet oxygen is measured.
Received: 7 October 2002 / Accepted: 8 February 2003 / Published online: 28 May 2003
RID="*"
ID="*"Corresponding author. Fax: +420-2/8689-0527, E-mail: kodym@fzu.cz 相似文献
14.
J. Ihlemann S. Müller S. Puschmann D. Schäfer M. Wei J. Li P.R. Herman 《Applied Physics A: Materials Science & Processing》2003,76(5):751-753
Submicron surface-relief gratings were fabricated on fused silica by F2-laser ablation with nanosecond duration pulses from a high-resolution 157-nm optical processing system. A 157 nm wavelength
projection mask was prepared by ArF-laser ablation to form a 20-μm period grating of equal lines and spaces. A 25-fold demagnification
of the mask by a Schwarzschild objective generated gratings of an 830-nm period and a 250 nm modulation depth, as characterized
by SEM, AFM and HeNe-laser beam diffraction.
Received: 24 April 2002 / Accepted: 25 April 2002 / Published online: 4 December 2002
RID="*"
ID="*"Corresponding author. Fax: +49-551/503 599, E-mail: jihle@llg.gwdg.de 相似文献
15.
LiMnO2 nanowire arrays were prepared using a porous anodic aluminum oxide (AAO) template from a sol–gel solution containing Li(OAc)
and Mn(OAc)2. Electron-microscope results showed that a uniform length and diameter of LiMnO2 nanowires were obtained, and the length and diameter of the LiMnO2 nanowires are dependent on the pore diameter and the thickness of the applied AAO template. X-ray diffraction and electron
diffraction pattern investigations demonstrate that LiMnO2 nanowires are a layered structure of LiMnO2 crystal. X-ray photoelectron spectroscopy analysis indicates that a material closely resembling stoichiometric layered LiMnO2 has been obtained.
Received: 2 September 2001 / Accepted: 6 January 2002 / Published online: 10 September 2002
RID="*"
ID="*"Corresponding author. Fax: +86-931/891-2582, E-mail: lihl@lzu.edu.cn 相似文献
16.
J.K. Jian X.L. Chen W.J. Wang L. Dai Y.P. Xu 《Applied Physics A: Materials Science & Processing》2003,76(2):291-294
Single-crystalline SnO2 nanowires, nanobelts and nanodendrites were synthesized by a simple gas-reaction route on a large scale at 900 °C. They were
characterized by means of X-ray powder diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), energy-dispersive
X-ray spectroscopy (EDS), transmission electron microscopy (TEM) and selected-area electron diffraction (SAED). FE-SEM images
showed that the products consisted of nanowires, nanobelts and nanodendrites that represent a novel morphology reported for
the first time. XRD, SAED and EDS indicated that they were single-crystalline tetragonal SnO2. The influence of experimental conditions on the morphologies of the products is discussed.
Received: 3 June 2002 / Accepted: 10 June 2002 / Published online: 10 September 2002
RID="*"
ID="*"Corresponding author. Fax: 86-10/82649531, E-mail: xlchen@aphy.iphy.ac.cn 相似文献
17.
C. Du Z. Wang J. Liu X. Xu K. Fu G. Xu J. Wang Z. Shao 《Applied physics. B, Lasers and optics》2002,74(2):125-127
Intracavity sum-frequency mixing of 1.06 μm and 532 nm in YCa4O(BO3)3 (YCOB) crystals cut for different type-I phase-matching directions of (θ,ϕ)=(106°,77.2°), (111°, 79.6°) and (65°, 82.8°)
was investigated in a compact diode-end-pumped acousto-optical Q-switched Nd:YVO4/KTP laser formed with a three-mirror folded resonator. The maximum 355-nm average output power of 124 mW was obtained in
the phase-matching direction of (106°, 77.2°) with a pump-to-ultraviolet conversion efficiency of 3.3% at the repetition frequency
of 20 kHz.
Received: 17 September 2001 / Revised version: 27 November 2001 / Published online: 17 January 2002 相似文献
18.
Shakeel Ahmed 《Optics Communications》2008,281(17):4211-4218
Electromagnetic scattering of an incident plane wave from a rectangular strip and strip grating, are presented semi-analytically. The strip and strip grating are simulated by joining parallel perfect electromagnetic conductor (PEMC) circular cylinders and are illuminated by a TMz incident plane wave. The PEMC medium does not allow electromagnetic energy to enter. An interface of this medium serves as an ideal boundary to the electromagnetic field. The solution is based on the application of the boundary conditions on the surface of each cylinder in terms of its local coordinate system. The technique is used to predict the scattered field pattern of PEMC strip and PEMC strip grating. 相似文献
19.
High efficiency continuous-wave tunable signal output of an intracavity singly resonant optical parametric oscillator based on periodically poled lithium niobate 下载免费PDF全文
In this paper we report on a continuous-wave (CW) intracavity singly
resonant optical parametric oscillator (ICSRO) based on periodically
poled LiNbO3 (PPLN) pumped by a diode-end-pumped CW
Nd:YVO4 laser. Considering the thermal lens effects and
diffraction loss, an optical ballast lens and a near-concentric
cavity are adopted for better operation. Through varying the grating
period and the temperature, the tunable signal output from 1406~nm
to 1513~nm is obtained. At a PPLN grating period of 29~μ m and a
temperature of 413~K, a maximum signal output power of 820~mW at
1500~nm is achieved when the 808~nm pump power is 10.9~W, leading to
an optical-to-optical conversion efficiency of 7.51%. 相似文献
20.
本文从自洽的费涅耳衍射积分方程出发,利用费涅耳数近似趋于无穷,计算了凹(平)面锯齿形和截端锯齿形衍射光栅稳定共振腔的共振模特性。结果指出:当光栅槽很浅,满足光栅自准直条件,在一定的角度范围内,腔内的场振幅分布近似与光栅的闪耀角无关。垂直于光栅槽方向(x方向)的场分布由m阶厄米-高斯函数和微扰项(m+1阶和m-1阶厄米-高斯函数)表示。微扰项随光栅倾角的增大而增大。当微扰项可以忽略不计时,倾斜的光栅可以和垂直于光轴、曲率半径为Γ1cos3θ(x方向)和Γ1cosθ(y方向,平行于栅槽方向)的长条凹镜等效。文中给出了栅、镜面上的场分布、稳定性条件、频谱分布及输出场特性。
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