共查询到20条相似文献,搜索用时 46 毫秒
1.
Ambika Nautiyal 《Optics Communications》2007,278(1):175-179
The white light continuum (WLC) generated in water/D2O mixture by pumping with the fundamental of ps Nd+3:YAG laser has been used as a variable frequency source for the sum frequency generation as well as for its amplification. 35 ps long pulses with 8 mJ energy at 1064 nm were mixed collinearly with the WLC generated by the same laser beam in a 20 mm thick BBO crystal. The obtained tunable output has been identified as the sum frequency between the fundamental and a portion of the WLC with the required phase matching. Theoretical simulations are also given along with a few initial experiments to use this combination for the difference frequency generation (optical parametric amplification) under non-collinear geometry. 相似文献
2.
W. J. Sun Q. P. Wang Z. J. Liu X. Y. Zhang F. Bai X. B. Wan G. F. Jin X. T. Tao Y. X. Sun 《Applied physics. B, Lasers and optics》2011,104(1):87-91
A high efficiency KTiOAsO4(KTA) intracavity optical parametric oscillator (IOPO) is demonstrated within a diode-side-pumped acousto-optically (AO) Q-switched two-rod Nd:YAG laser. With a 25-mm-long X-cut KTA crystal, efficient parametric conversions to signal (1.54 μm) and idler (3.47 μm) waves are realized. The highest
output power of 15.8 W including 12.7 W signal and 3.1 W idler power is obtained at a repetition rate of 7.5 kHz and a pump
power of 208 W, corresponding to an optical-to-optical conversion efficiency of up to 7.6%. The signal pulse duration is 32 ns
with a peak power of 53 kW. At a repetition rate of 12.5 kHz and the pump power of 208 W, the highest idler power of 3.4 W
is obtained with a peak power of 14 kW and a pulse duration of 19 ns. And the beam quality factors (M
2) of the signal and idler waves are determined to be around 2 and 20, respectively. 相似文献
3.
Glasses xLi2O–(50-x)(MoO3)2–50P2O5 with x = 10, 20, 30, and 40 mol% were prepared and their optical and electrical properties were investigated. Analysis of the IR
spectra revealed that the Li+ ions act as a glass modifier that enter the glass network by breaking up other linkages and creating non-bridging oxygens
in the network. The optical absorption edge of the glasses was measured for specimens in the form of thin blown films and
the optical absorption spectra of those were recorded in the range 200–800 nm. From the optical absorption edges studies,
the optical band gap (E
opt) and the Urbach energy (E
e) values have been evaluated by following the available semi-empirical theories. The linear variation of (αhν)1/2 with hν, is taken as evidence of indirect interband transitions. The E
opt values were found to decrease with increasing Li2O content by causing increase in the number of non-bridging oxygens in network. The Urbach tail analysis gives the width of
localized states between 0.48 and 0.74 eV. 相似文献
4.
A. Rihan E. Andrieux T. Zanon-Willette S. Briaudeau M. Himbert J.-J. Zondy 《Applied physics. B, Lasers and optics》2011,102(2):367-374
We report on a widely tunable continuous-wave single-frequency pump-resonant signal-resonant optical parametric oscillator
(PRSRO) delivering 20 mW to 50 mW of idler power spanning an octave bandwidth in the mid-infrared (1.7 μm and 3.5 μm). The
PRSRO is pumped by a Ti:Al2O3 ring laser delivering 760 mW around λ
p
=795 nm, and thanks to the pump enhancement a threshold as low as 110 mW is achieved with a multi-grating temperature-tuned
MgO-doped periodically-poled LiNbO3. This PRSRO will be used for multi-species trace gas sensing based on cavity ring-down spectroscopy. 相似文献
5.
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
6.
We have theoretically investigated the thermal characteristics of double-channel ridge–waveguide InGaAs/InAlAs/InP quantum
cascade lasers (QCLs) using a two-dimensional heat dissipation model. The temperature distribution, heat flow, and thermal
conductance (G
th) of QCLs were obtained through the thermal simulation. A thick electroplated Au around the laser ridges helps to improve
the heat dissipation from devices, being good enough to substitute the buried heterostructure (BH) by InP regrowth for epilayer-up
bonded lasers. The effects of the device geometry (i.e., ridge width and cavity length) on the G
th of QCLs were investigated. With 5 μm thick electroplated Au, the G
th is increased with the decrease of ridge width, indicating an improvement from G
th=177 W/K⋅cm2 at W=40 μm to G
th=301 W/K⋅cm2 at W=9 μm for 2 mm long lasers. For the 9 μm×2 mm epilayer-down bonded laser with 5 μm thick electroplated Au, the use of InP
contact layer leads to a further improvement of 13% in G
th, and it was totally raised by 45% corresponding to 436 W/K⋅cm2 compared to the epilayer-up bonded laser with InGaAs contact layer. It is found that the epilayer-down bonded 9 μm wide BH
laser with InP contact layer leads to the highest G
th=449 W/K⋅cm2. The theoretical results were also compared with available obtained experimentally data. 相似文献
7.
D. Ambika V. Kumar C. S. Suchand Sandeep R. Philip 《Applied physics. B, Lasers and optics》2009,97(3):661-664
Thin films of (Pb1−x
Sr
x
)TiO3, x=0,0.5,1.0 have been prepared on glass substrates by the chemical-solution method using the spin-coating technique. The optical
nonlinearity in the visible spectral region is investigated using short (5 ns) laser pulses at the off-resonant wavelength
of 532 nm employing the open aperture z-scan technique. It is found that the third order nonlinear absorption is dependent
on the lead content of the films, with the compositions x=0, 0.5 exhibiting large values (β∼10−7 m/W), thereby suggesting the possible use of these materials as optical limiters. No optical nonlinearity is observed for
the composition with x=1.0. 相似文献
8.
Bin Yang Hengzhi Chen Mingfu Zhang Feiyan Wang Kokwai Cheah Wenwu Cao 《Applied Physics A: Materials Science & Processing》2009,96(4):1017-1021
Bi3TiNbO9 (BTN) thin films with layered perovskite structure were fabricated on fused silica by pulsed laser deposition. The XRD pattern
revealed that the films are single-phase perovskite and highly (00l) textured. Their fundamental optical constants, such as band gap, linear refractive index, and linear absorption coefficient,
were obtained by optical transmittance measurements. The dispersion relation of the refractive index vs. wavelength follows
the single electronic oscillator model. The nonlinear optical absorption of the films was investigated by single beam Z-scan
method at a wavelength of 800 nm with laser duration of 80 fs. We obtained the nonlinear absorption coefficient β=1.44×10−7 m/W. The results show that the BTN thin films are promising for applications in absorbing-type optical devices. 相似文献
9.
Investigation of third-order nonlinear optical properties of NNDC-doped PMMA thin films by Z-scan technique 总被引:1,自引:0,他引:1
Jingwei Chen Xinqiang Wang Quan Ren P. S. Patil Tingbin Li Hongliang Yang Jingnan Zhang Guochao Li Luyi Zhu 《Applied Physics A: Materials Science & Processing》2011,105(3):723-731
A novel chalcone derivative, (2E)-1-(2,4-di- chloro-5-fluorophenyl)-3-[4-dimethylamino)phenyl]prop-2-en-1-one, abbreviated as NNDC, was prepared and characterized
by elemental analyses, infrared (IR) and proton nuclear magnetic resonance (1H NMR) spectrum, and thermal analyses. The NNDC-doped poly(methyl methacrylate) (PMMA) thin films with five different doping
concentrations by weight were prepared by using a spin-coating method. Their linear optical properties were investigated by
using a prism coupling measuring system. The third-order nonlinear optical properties of NNDC in 1,2-dichloroethane (NNDC/1,2-dichloroethane)
solution and NNDC-doped PMMA (NNDC/PMMA) films were investigated by using the laser Z-scan technique with 20 ps pulses at
532 nm. A self-focusing effect was observed from the Z-scan curves for solution and thin films and the nonlinear refractive
index of the film increases with the increase of the doping concentration. In addition, nonlinear absorption was negligible
for all samples. The magnitude of third-order nonlinear refraction index n
2 and the third-order nonlinear susceptibility χ
(3) for thin films were 10−15 m2/W and 10−9 esu, respectively, which are about three orders larger than that of NNDC/1,2-dichloroethane solution. Some necessary analyses
were presented. The results show that this material is a promising candidate for application in the nonlinear optical devices
at 532 nm. 相似文献
10.
Qiming Liu Xuan He Ting Hu Chang Gao Yanan Hou Xiujian Zhao 《Applied Physics A: Materials Science & Processing》2011,102(1):245-249
0.56GeS2-0.24Ga2S3-0.2KI (mol%) chalcohalide glass was prepared and second-harmonic generation was observed by the thermal poling process. Second-order
optical nonlinearity in the glass was also investigated by different poling temperature, voltage and time to optimize the
poling parameters to improve χ
(2). The maximum χ
(2) in our study as large as 3.74 pm/V was obtained under the optimized poling condition with 5.2 kV, 260°C and 120 minutes. 相似文献
11.
Lei Gao Yanyan Huang 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,33(2):165-171
The effective linear and nonlinear optical properties of metal/dielectric composite media, in which ellipsoidal metal inclusions
are distributed in shape, are investigated. The shape distribution function P(L
x, L
y) is assumed to be 2Δ-2θ(L
x - 1/3 + Δ/3)θ(L
y - 1/3 + Δ/3)θ(2/3 + Δ/3 - L
x - L
y), where θ( . . . ) is the Heaviside function, Δ is the shape variance and Li are the depolarization factors of the ellipsoidal inclusions along i-symmetric axes (i = x, y). Within the spectral representation, we adopt Maxwell-Garnett type approximation to study the effect of shape variance Δ
on the effective nonlinear optical properties. Numerical results show that both the effective linear optical absorption α
∼ ωIm() and the modulus of the effective third-order optical nonlinearity enhancement |χ(3)
e|/χ(3)
1 exhibit the nonmonotonic behavior with Δ. Moreover, with increasing Δ, the optical absorption and the nonlinearity enhancement
bands become broad, accompanied with the decrease of their peaks. The adjustment of Δ from 0 to 1 allows us to examine the
crossover behavior from no separation to large separation between optical absorption and nonlinearity enhancement peaks. As
Δ → 0, i.e., the ellipsoidal shape deviates slightly from the spherical one, the dependence of |χ(3)
e|/χ(3)
1 on Δ becomes strong first and then weak with increasing the imaginary part of inclusions' dielectric constant. In the dilute
limit, the exact formula for the effective optical nonlinearity is derived, and the present approximation characterizes the
exact results better than old mean field one does.
Received 10 December 2002 Published online 4 June 2003
RID="a"
ID="a"e-mail: lgaophys@pub.sz.jsinfo.net 相似文献
12.
Wenwei Ge Hong Liu Xiangyong Zhao Xiaobing Li Xiaoming Pan Di Lin Haiqing Xu Xiangping Jiang Haosu Luo 《Applied Physics A: Materials Science & Processing》2009,95(3):761-767
In this paper, a single crystal of 0.96Na0.5Bi0.5TiO3-0.04BaTiO3 with dimensions of Φ 30×10 mm was grown by the top-seeded-solution growth method. X-ray powder diffraction results show that the as-grown crystal
possesses the rhombohedral perovskite-type structure. The dielectric, piezoelectric and electrical conductivity properties
were systematically investigated with 〈001〉, 〈110〉 and 〈111〉 oriented crystal samples. The room-temperature dielectric constants
for the 〈001〉, 〈110〉 and 〈111〉 oriented crystal samples are found to be 650, 740 and 400 at 1 kHz. The (T
m, ε
m) values of the dielectric temperature spectra are almost independent of the crystal orientations; they are (306°C, 3718),
(305°C, 3613) and (307°C, 3600) at 1 kHz for the 〈001〉, 〈110〉 and 〈111〉 oriented crystal. The optimum poling conditions were
obtained by investigating the piezoelectric constants d
33 as a function of poling temperature and poling electric field. For the 〈001〉 and 〈110〉 crystal samples, the maximum d
33 values of 146 and 117 pC/N are obtained when a poling electric field of 3.5 kV/mm and a poling temperature of 80°C were applied
during the poling process. The as-grown 0.96Na0.5Bi0.5TiO3-0.04BaTiO3 crystal possesses a relatively large dc electrical conductivity, especially at higher temperature, having a value of 1.98×10−11 Ω−1⋅m−1 and 3.95×10−9 Ω−1⋅m−1 at 25°C and 150°C for the 〈001〉 oriented crystal sample. 相似文献
13.
The electron paramagnetic resonance study of Cu2+-doped bis(l-asparaginato)Mg(II) is performed at room temperature. Two magnetically non-equivalent sites for Cu2+ are observed. The spin-Hamiltonian parameters evaluated by fitting spectra to the crystalline field of rhombic symmetry are
as follows: g
x
= 2.0420 ± 0.0002, g
y
= 2.0808 ± 0.0002, g
z
= 2.3600 ± 0.0002, A
x
= (99 ± 2) × 10−4 cm−1, A
y
= (108 ± 2) × 10−4 cm−1, A
z
= (140 ± 2) × 10−4 cm−1. The ground state wave function of Cu2+ is also determined. The g-anisotropy is estimated and compared with the experimental value. Further, with the help of optical study the nature of bonding
of a metal ion with different ligands in the complex is discussed. 相似文献
14.
H. Kim G. P. Kushto R. C. Y. Auyeung A. Piqué 《Applied Physics A: Materials Science & Processing》2008,93(2):521-526
Fluorine-doped tin oxide (FTO) thin films have been investigated as an alternative to indium tin oxide anodes in organic photovoltaic
devices. The structural, electrical, and optical properties of the FTO films grown by pulsed laser deposition were studied
as a function of oxygen deposition pressure. For 400 nm thick FTO films deposited at 300°C and 6.7 Pa of oxygen, an electrical
resistivity of 5×10−4 Ω-cm, sheet resistance of 12.5 Ω/□, average transmittance of 87% in the visible range, and optical band gap of 4.25 eV were obtained. Organic photovoltaic (OPV)
cells based on poly(3-hexylthiophene)/[6,6]-phenyl-C61-butyric acid methyl ester bulk heterojunctions were prepared on FTO/glass electrodes and the device performance was investigated as a function of FTO
film thickness. OPV cells fabricated on the optimum FTO anodes (∼300–600 nm thick) exhibited power conversion efficiencies
of ∼3%, which is comparable to the same device made on commercial ITO/glass electrodes (3.4%). 相似文献
15.
Electron paramagnetic resonance (EPR) study of Cu2+-doped sodium zinc sulfate tetrahydrate is done at liquid nitrogen temperature. Two magnetically equivalent sites for Cu2+ are observed. The spin-Hamiltonian parameters determined by fitting the EPR spectra to the rhombic-symmetry crystalline field
are g
x
= 2.2356, g
y
= 2.0267, g
z
= 2.3472, A
x
= 27 × 10−4 cm−1, A
y
= 54 × 10−4 cm−1and A
z
= 88 × 10−4 cm−1. The ground state wave function is also determined. The g-anisotropy is evaluated and compared with the experimental value. With the help of optical study, the nature of bonding in
the complex is discussed. 相似文献
16.
We report a continuous-wave singly resonant optical parametric oscillator (SRO) with more than 12 W of idler power at 3414
nm when it was operated at 30°C. The SRO was directly pumped by a single-frequency, ytterbium-doped fiber laser with 49 W
linear polarization pump powers, and based on 50 mm long periodically poled MgO:LiNbO3 crystal (PPMgLN) in two-mirror linear cavity with 30.5 μm grating period. It’s pump power at threshold was 5.4 W. The slope-efficiency
and quantum-limited performance reached 26 and 79.2%, respectively. The beam polarization matched the e → e + e interaction in crystal. The idler waves were temperature tuned in the range of 3654 to 3811 nm and 3248 to 3414 nm based
on two 50 mm long PPMgLN with 29.5 and 30.5 μm grating period. To the best of our knowledge, this is the highest continuouswave
mid-IR output obtained for a fiber laser pumped optical parametric oscillator (OPO). 相似文献
17.
Zhang Qingfeng Jiang Shenglin Zeng Yike Fan Maoyan Wang Qingping Zhang Guangzu Zhang Yangyang Yu Yan Wang Jing 《Applied Physics A: Materials Science & Processing》2011,103(4):1159-1163
(Pb0.87La0.02Ba0.1)(Zr0.7Sn0.3−x
Ti
x
)O3 (PLBZST, 0.06≤x≤0.09) antiferroelectric ceramics were fabricated by conventional solid state reaction process, and their ferroelectric, dielectric,
and pyroelectric properties were systemically investigated. PLBZST with different Ti content were all confirmed to be in an
antiferroelectric phase at T=50°C, which is close to the lowest phase transition temperature. Compared with conventional FE ceramics, PLBZST antiferroelectric
ceramics exhibited higher electric field induced pyroelectric coefficient (p). As the content of Ti increased from 0.06 to 0.09, the pyroelectric coefficient increased from 1000 to 6500 μC/m2K under a 500 V/mm DC bias field. The maximum pyroelectric coefficient of 8400 μC/m2K was obtained at x=0.09 when an 850 V/mm DC bias field was applied, which is far larger than that of conventional phase transition pyroelectric
materials. Large pyroelectric response is beneficial for the development of infrared detectors and thermal imaging sensors. 相似文献
18.
Modified parametric coupled equations for three-wave interaction in non-collinear optical parametric chirped-pulse amplification
(OPCPA) are presented, in which the effects from the non-collinear configuration have been taken into account. By utilizing
this new model, a two-stage OPCPA system based on a BBO crystal is numerically calculated with a split-step Fourier transform
algorithm. Tracing the dynamics of the signal wave in the crystal reveals that in the first stage spectral gain narrowing
occurs due to the weak input signal intensity and the non-uniform temporal distribution of the pump light. However, in the
saturation regime the spectrum of the signal will be broadened as a consequence of back conversion. The simulation shows that
it is crucial to correctly control the experimental parameters to balance both processes. For maximizing the energy-bandwidth
product (EBP), an optimized configuration is sought by examining several parameters such as pump intensity, seed energy and
crystal length. With a pump intensity of 7.75 GW/cm2 and a crystal length between 3.75 and 4.25 mm pulses with a sub-10 fs duration can be amplified with a total gain of up to
1.7×106. 相似文献
19.
A. A. Kaminskii H. Rhee H. J. Eichler K. Ueda K. Oka H. Shibata 《Applied physics. B, Lasers and optics》2008,93(4):865-872
We report the experimental investigations of nonlinear-laser effects in LuVO4 vanadate under one-micron picosecond Nd3+:Y3Al5O12 pumping. In this tetragonal host-crystal for Ln3+ lasants for the first time we excited ultra-broad, more than one and half octave (13500 cm−1) Raman induced Stokes and anti-Stokes generation combs and observed multi-step cascaded parametric χ
(3)-lasing in UV spectral region. All generation lines were identified and attributed to SRS-promoting modes of the crystal (ω
SRS1≈900 cm−1 and ω
SRS2≈113 cm−1). We classified this vanadate as a promising material for self-Raman laser converters. 相似文献
20.
O. Arnoult F. Nez L. Julien F. Biraben 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2010,60(2):243-256
This article reports the first optical frequency measurement of the 1S–3S transition in hydrogen. The excitation of this transition
occurs at a wavelength of 205 nm which is obtained with two frequency doubling stages of a titanium sapphire laser at 820 nm.
Its frequency is measured with an optical frequency comb. The second-order Doppler effect is evaluated from the observation
of the motional Stark effect due to a transverse magnetic field perpendicular to the atomic beam. The measured value of the
1S1/21\mathrm{S}_{1/2}(F = 1)-3S1/2(F = 1) frequency splitting is 2 922 742 936.729(13) MHz with a relative uncertainty of 4.5 × 10-12. After the measurement of the 1S–2S frequency, this result is the most precise of the optical frequencies in hydrogen. 相似文献