共查询到20条相似文献,搜索用时 437 毫秒
1.
G. Hakhumyan D. Sarkisyan A. Sargsyan A. Atvars M. Auzinsh 《Optics and Spectroscopy》2010,108(5):685-692
It has been experimentally demonstrated that the use of the effect of significant narrowing of the fluorescence spectrum from
a nanocell that contains a column of atomic Rb vapor with a thickness of L = 0.5λ (where λ = 794 nm is the wavelength of laser radiation, whose frequency is resonant with the atomic transition of
the D
1 line of Rb) and the application of narrowband diode lasers allow the spectral separation and investigation of changes in
probabilities of optical atomic transitions between levels of the hyperfine structure of the D
1 line of 87Rb and 85Rb atoms in external magnetic fields of 10–2500 Gs (for example, for one of transitions, the probability increases ∼17 times).
Small column thicknesses (∼390 nm) allow the application of permanent magnets, which facilitates significantly the creation
of strong magnetic fields. Experimental results are in a good agreement with the theoretical values. The advantages of this
method over other existing methods are noted. The results obtained show that a magnetometer with a local spatial resolution
of ∼390 nm can be created based on a nanocell with the column thickness L = 0.5λ. This result is important for mapping strongly inhomogeneous magnetic fields. 相似文献
2.
A.B. Mundt A. Kreuter C. Russo C. Becher D. Leibfried J. Eschner F. Schmidt-Kaler R. Blatt 《Applied physics. B, Lasers and optics》2003,76(2):117-124
We demonstrate coherent coupling of the quadrupole S1/2D5/2 optical transition of a single trapped 40Ca+ ion to the standing wave field of a high-finesse cavity. The dependence of the coupling on temporal dynamics and spatial
variations of the intracavity field is investigated in detail. By precisely controlling the position of the ion in the cavity
standing wave field and by selectively exciting vibrational state-changing transitions the ion’s quantized vibration in the
trap is deterministically coupled to the cavity mode. We confirm coherent interaction of ion and cavity field by exciting
Rabi oscillations with short resonant laser pulses injected into the cavity, which is frequency-stabilized to the atomic transition.
Received: 23 August 2002 / Published online: 8 January 2003
RID="*"
ID="*"Corresponding author. E-mail: christoph.becher@uibk.ac.at
RID="**"
ID="**"Present address: Time and Frequency Division, National Institute of Standards and Technology, Boulder, CO 80305, USA 相似文献
3.
We report on a passively Q-switched diode-pumped Nd:YVO4 laser polarized along the a axis (corresponding to the smallest value of emission cross section at 1064 nm), generating 157-μJ
pulses with 6.0-ns time duration (>20 kW peak power) and 3.6 W of average power at 1064 nm with good beam quality (M2<1.4). The selection of the polarization was performed by a novel technique relying on the birefringence of the laser crystal
and on the misalignment sensitivity of the resonator.
Received: 30 September 2002 /
Revised version: 22 November 2002 / Published online: 19 March 2003
RID="*"
ID="*"Corresponding author. Fax: +39-382/422583, E-mail: agnesi@ele.unipv.it 相似文献
4.
J.C. Bermudez Gutierrez M.J. Damzen V.J. Pinto-Robledo A.V. Kir’yanov J.J. Soto-Bernal 《Applied physics. B, Lasers and optics》2003,76(1):13-16
The analysis of compact CW diode-side-pumped grazing-incidence-geometry Nd:YVO4 laser designs is presented. An output power of 5 W (λ=1064 nm) was produced at 17 W of diode pump (conversion efficiency
of 30%) in single transverse TEM00 mode operation at high laser beam quality (Mx
2≈1.05 and My
2≈1.01). The resonator geometry was analyzed by applying generalized 4×4 matrix modeling of the spatial mode size, including
the impact on the laser operation of cavity astigmatism and a thermal lens in the laser slab. The simplicity and compactness
of the laser cavities allow their use for technological applications.
Received: 31 July 2002 / Published online: 22 January 2003
RID="*"
ID="*"Corresponding author. Fax: +44-20/7594-7744, E-mail: m.damzen@ic.ac.uk 相似文献
5.
S. Chakrabarti B. Ray P. N. Ghosh 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,42(3):359-368
The effects of a strong control or pump laser, counter propagating
or copropagating with the probe beam, on the probe absorption spectra of
85Rb and 87Rb-D2 transitions have been investigated inside
a room temperature Rb vapour cell. In both cases a set of strong velocity
selective resonance dips are observed at different velocities. Their
movements across the Doppler broadened probe absorption profile have been
studied for different lock frequencies of the control laser. These spectra
are modified by optical pumping effects due to the presence of another
hyperfine component of the ground state. A repumping laser, from the dark
hyperfine component of the ground level transfers almost 75% of the atoms
from the dark state to the pump probe cycle hence reducing the optical
pumping effect. A numerical simulation is done to explain the observed
spectra. The effect of a control laser on the Lamb dip spectrum of the probe
laser has also been investigated. The control beam is used to improve the
strength of a weak hyperfine dip on the Doppler broadened probe spectrum.
The strength of the hyperfine dip increases by a factor of 3.2 in presence
of the control laser. The observed dips show that pump-probe spectroscopy
can be used as velocity selectors of atoms. 相似文献
6.
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
7.
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
8.
T. Okazaki T. Shimada K. Suenaga Y. Ohno T. Mizutani J. Lee Y. Kuk H. Shinohara 《Applied Physics A: Materials Science & Processing》2003,76(4):475-478
Electronic properties of Gd@C82 metallofullerene peapods, (Gd@C82)n@SWNTs, were investigated by electron energy-loss spectroscopy (EELS), scanning tunneling microscopy and spectroscopy (STM/STS),
and field-effect transistor (FET) transport measurements. The results indicate that the electronic structure of Gd@C82 metallofullerene peapods is completely different from that of intact single-walled nanotubes (SWNTs). For example, Gd@C82-peapod-FETs show ambipolar behavior which is not observed in the empty SWNT-FETs under our experimental conditions. Furthermore,
in semiconducting nanotubes the band gap can be varied from ∼0.5 to ∼0.1 eV using inserted Gd@C82 endohedral metallofullerenes with a spatial periodicity of 1.1 to 8.0 nm, depending on the density of the fullerenes. The
present findings suggest that metallofullerene peapods may point the way toward novel electronic devices.
Received: 6 September 2002 / Accepted: 25 October 2002 / Published online: 10 March 2003
RID="*"
ID="*"Corresponding author. Fax: +81-52/789-1169, E-mail: noris@cc.nagoya-u.ac.jp 相似文献
9.
T. Yang F. Meng Y. Zhao Y. Peng Y. Li J. Cao C. Gao Z. Fang E. Zang 《Applied physics. B, Lasers and optics》2012,106(3):613-618
The precision hyperfine structures of the 127
I
2 transitions at 561.4 nm are measured by the heterodyne beat between two home-made 127
I
2-stabilized Nd:YAG lasers. The theoretical distributions of the observed transitions’ hyperfine sublevels are used to identify
the two transitions. High-accuracy hyperfine constants are obtained by fitting the measured hyperfine splittings to the four-term
Hamiltonian, which includes the electric quadruple, spin-rotation, tensor spin–spin and scalar spin–spin interactions. The
absolute frequencies of the observed four transitions are measured by an optical frequency comb based on a mode-locked erbium-fiber
laser. 相似文献
10.
Ultrahigh-efficiency TEM00 operation is demonstrated in a diode-pumped Nd:YVO4 laser in a bounce amplifier geometry using a specially designed astigmatically optimised cavity configuration. Optical efficiency
>68% is demonstrated and up to 27.1 W of output power for multimode operation. For single-mode TEM00 operation, an output power of 23.1 W for 39.5 W of diode pumping was produced with beam propagation parameters of Mx
2=1.3 and My
2=1.1.
Received: 10 October 2002 / Revised version: 9 December 2002 / Published online: 19 March 2003
RID="*"
ID="*"Corresponding author. Fax: +44-20/7594-7744, E-mail: a.minassian@ic.ac.uk 相似文献
11.
We have grown crystals Na0.4Y0.6F2.2:Ho3+ (NYF:Ho3+) by the Bridgman-Stockbarger method. The optical spectra and luminescence kinetics of NYF:Ho3+ crystals have been studied. Based on the analysis of low-temperature absorption spectra, we determine the structure of the
Stark splitting of holmium levels in NYF:Ho3+ crystals. From absorption spectra examined at T = 300 K, we calculate absorption cross-section spectra and oscillator strengths of transitions from the ground state of holmium
to excited multiplets. We show that the absorption spectra of NYF:Ho3+ crystals consist of broad bands that lie in the UV, visible, and near-IR ranges. The most intense bands are observed in the
visible range, they correspond to transitions 5
I
8 → (5
F
1, 5
G
6) and 5
I
8 → (5
F
4, 5
S
2), and their maximal absorption cross sections are σabsmax (λ = 450.3 nm) = 1.16 × 10−20 cm2 and σabsmax (λ = 535.1 nm) = 0.9 × 10−20 cm2. The intensity parameters Ω
t
have been calculated by the Judd-Ofelt method taking into account 10, 12, and 20 transitions from the 5
I
8 ground state to excited multiplets. We show that, with an increasing number of transitions taken into account in the calculation,
the parameters Ω
t
somewhat increase. For 20 transitions, we have obtained the following intensity parameters: Ω2 = 0.97 × 10−20, Ω4 = 1.74 × 10−20, and Ω6 = 1.15 × 10−20 cm2. With these parameters, we have calculated the probabilities of radiative transitions, the radiative lifetimes, and the branching
ratios. The rates of multiphoton nonradiative transitions have been estimated. The luminescence decay kinetics from excited
holmium levels 5
F
3 (5
F
4, 5
S
2) and 5
F
5 have been studied upon selective excitation in the range of 490 nm, and the lifetimes of these levels have been experimentally
determined. We find that the calculated and experimental rates of radiative and nonradiative relaxation from excited holmium
levels agree well with each other. We show that, upon pumping in the range of 490 nm, the multiplet (5
F
4, 5
S
2) is populated as a result of the radiative and nonradiative excitation relaxation from the 5
F
3 level, while the lower-lying 5
F
5 level is populated due to direct radiative transitions 5
F
3, 2 → 5
F
5, obviating the cascade scheme 5
F
3 → (5
F
4, 5
S
2) ↝ 5
F
5. We conclude that NYF:Ho3+ crystals are processable; admit doping by holmium in high concentrations (up to 100%); and, with respect to all their radiative
characteristics, can be considered as potential active media for solid-state continuously tunable lasers in the IR and visible
ranges. 相似文献
12.
G. Schrems M.P. Delamare N. Arnold P. Leiderer D. Bäuerle 《Applied Physics A: Materials Science & Processing》2003,76(5):847-849
The influence of the ‘storage time’ τs on the threshold fluence φcl and the efficiency in dry laser cleaning is investigated. τs denotes the time between the deposition of particles and the cleaning. As a model system we employed silica spheres with
diameters of 500 nm and 1500 nm on commercial silicon wafers and single-pulse KrF excimer laser radiation (τFWHM=28 ns). For the 1500-nm silica spheres, φcl was found to increase from about 65 mJ/cm2 to 125 mJ/cm2 for storage times of 4 h and 362 h, respectively. For 500-nm silica spheres the increase in the threshold fluence was less
than 20% for storage times up to 386 h.
Received: 12 July 2002 / Accepted: 12 July 2002 / Published online: 29 January 2003
RID="*"
ID="*"Corresponding author. E-mail:dieter.baeurle@jku.at 相似文献
13.
β-Ga2O3 nanowires have been synthesized using Ga metal and H2O vapor at 800 °C in the presence of Ni catalyst on the substrate. Remarkable reduction of the diameter and increase of the
length of the Ga2O3 nanowires are achieved by separation of Ga metal and H2O vapor before they reach the substrate. Transmission electron microscopy analyses indicate that the β-Ga2O3 nanowires possess a single-crystalline structure. Photoluminescence measurements show two broad emission bands centered at
290 nm and 390 nm at room temperature.
Received: 27 June 2002 / Accepted: 7 October 2002 / Published online: 17 December 2002
RID="*"
ID="*"Corresponding author. Fax: +886-6/234-4496, E-mail: wujj@mail.ncku.edu.tw 相似文献
14.
V.C. Selvaraju S. Asokan V. Srinivasan 《Applied Physics A: Materials Science & Processing》2003,77(1):149-153
The I–V characteristics of bulk As40Te60-xSex and As35Te65-xSex glasses have been studied with a current sweep of 0–18 mA-0, over a wide range of compositions (4≤x≤22). All the glasses
studied showed a threshold electrical switching behaviour. The number of switching cycles withstood by the samples has been
found to depend on the ON-state current. It is seen that the switching voltages increase with increase in selenium content.
Further, the switching voltages are found to be almost independent of the thickness of the sample (d), in the range 0.18–0.3 mm.
Also, the switching voltages and the number of switching cycles withstood by the samples are found to decrease with temperature.
Received: 6 November 2002 / Accepted: 8 November 2002 / Published online: 29 January 2003
RID="*"
ID="*"Corresponding author. Fax: +91-80/360-0135, E-mail: sasokan@isu.iisc.ernet.in 相似文献
15.
It is shown experimentally that use of fluorescence and transmission spectra obtained from nanocells with the thickness of
column of rubidium atomic vapor L = λ/2 and L = λ, respectively (λ = 794 nm is the wavelength of laser radiation close to resonance with D
1-line transition of Rb atoms), by means of a narrowband diode laser allows spectral separation and study of variations of
probabilities of atomic transitions between ground and excited states of hfs of D
1 lines of 85Rb and 87Rb atoms in the range of magnetic fields from 10 to 5000 G. Small thickness of atomic vapor column (∼390 nm and ∼794 nm) allows
applying permanent magnets simplifying essentially creation of strong magnetic fields. Advantages of this technique are discussed
as compared with the technique of saturated absorption. The obtained results show that a nanocell with submicrom thickness
of vapor column may serve as a basis for designing a magnetometer with submicron local spatial resolution which is important
in case of measuring strongly inhomogeneous magnetic fields. Experimental data are in good agreement with the theoretical
results. 相似文献
16.
M. Samsel-Czekała G. Kontrym-Sznajd G. Döring W. Schülke J. Kwiatkowska F. Maniawski S. Kaprzyk A. Bansil 《Applied Physics A: Materials Science & Processing》2003,77(1):87-92
A reconstruction technique based on the solution of the Radon transform in terms of Jacobi polynomials is used to obtain the
3D electron momentum density, ϱ(p), from nine high-resolution Compton profiles (CPs) for a Cu0.9Al0.1 disordered alloy single crystal. The method was also applied to theoretical CPs computed within the Korringa–Kohn–Rostoker
coherent potential approximation (KKR-CPA) first-principles scheme for the same nine orientations of the crystal. The experimental
ϱ(p) is in satisfactory agreement with the theoretical ϱ(p), shows most details of the Fermi surface (FS) and exhibits electron correlation effects. We comment on the map of the FS
obtained by folding the reconstructed ϱ(p) into the first Brillouin zone, which yields the occupation number density, ϱ(k). A test of the validity of data via a consistency condition (within our reconstruction algorithm) as well as the propagation
of experimental noise in the reconstruction of both ϱ(p) and ϱ(k) are investigated.
Received: 24 October 2001 / Accepted: 20 January 2002 / Published online: 3 June 2002
RID="*"
ID="*"Corresponding author. Fax: +48-71/344-10-29, E-mail: samsel@int.pan.wroc.pl 相似文献
17.
G.S. Wang X.J. Meng Z.Q. Lai J. Yu J.L. Sun S.L. Guo J.H. Chu 《Applied Physics A: Materials Science & Processing》2003,76(1):83-86
Ferroelectric Bi3.25La0.75Ti3O12 (BLT) thin films have been grown on Pt/Ti/SiO2/Si substrates by chemical solution methods. X-ray diffraction analysis shows that BLT thin films are polycrystalline with
(171)-preferential orientation. Atomic force microscopy investigation shows that they have large grains about 120 nm in size.
A Pt/BLT/Pt capacitor has been fabricated and showed excellent ferroelectricity, with a remnant polarization and coercive
field of 24 μC/cm2 and 116 kV/cm, respectively. The capacitor shows no polarization fatigue up to 109 switching cycles. The optical constants (n,k) of the BLT thin films in the wavelength range 0.35–1.7 μm were obtained by
spectroscopic ellipsometry measurements, and the band-gap energy was found to be about 3.25 eV.
Received: 16 October 2001 / Accepted: 6 January 2002 / Published online: 3 June 2002
RID="*"
ID="*"Corresponding author. Fax: +86-21/65830-734, E-mail: gswang@mail.sitp.ac.cn 相似文献
18.
Efficient room-temperature operation of 4
F
3/24
I
9/2 transitions in diode-end-pumped Nd:YAG lasers at 946 nm and 938.5 nm is reported. 7.0-W continuous-wave output power at 946 nm
and 3.9 W at 938.5 nm have been obtained. An analytical model has been developed for the quasi-three-level laser including
the influence of energy-transfer upconversion. Frequency doubling of these transitions in periodically poled KTP generated
blue light at 473 nm and 469 nm. Both single-pass extra-cavity as well as intracavity schemes have been investigated.
Received: 31 July 2002 / Published online: 5 February 2003
RID="*"
ID="*"Corresponding author. Fax: +46-8/750-5430, E-mail: stefan.bjurshagen@acreo.se 相似文献
19.
G. de la Paliza O. Caballero A. García-Cabañes M. Carrascosa J.M. Cabrera 《Applied physics. B, Lasers and optics》2003,76(5):555-559
Photovoltaic currents along the c axis have been measured in α-phase LiNbO3 proton-exchanged waveguides at several visible wavelengths for a guided-beam configuration. The light-intensity dependence
is superlinear and all experimental curves are very well fitted by computer simulations using a two-centre model, with Fe2+/Fe3+ as primary and NbLi
4+/NbLi
5+ as secondary photovoltaic centres. The superlinear behaviour arises from a much higher effective photovoltaic length of NbLi
4+ (small polaron) compared with that of Fe2+. In β1-phase guides, the photocurrents are much smaller than in α-phase guides and apparently do not show superlinear behaviour.
Received: 22 October 2002 / Revised version: 6 January 2003 / Published online: 12 May 2003
RID="*"
ID="*"Corresponding author. Fax: +34-91/3978-579, E-mail: m.carrascosa@uam.es 相似文献
20.
I. N. Ogorodnikov N. E. Poryvay I. N. Sedunova A. V. Tolmachev R. P. Yavetskiy 《Physics of the Solid State》2011,53(2):263-270
The thermally stimulated recombination processes and luminescence in crystals of the lithium borate family Li6(Y,Gd,Eu)(BO3)3 have been investigated. The steady-state luminescence spectra under X-ray excitation (X-ray luminescence spectra), the temperature
dependences of the X-ray luminescence intensity, and the glow curves for the Li6Gd(BO3)3, Li6Eu(BO3)3, Li6Y0.5Gd0.5(BO3)3: Eu, and Li6Gd(BO3)3: Eu compounds have been measured in the temperature range 90–500 K. In the X-ray luminescence spectra, the band at 312 nm
corresponding to the 6
P
J
→ 8
S
7/2 transitions in the Gd3+ ion and the group of lines at 580–700 nm due to the 5
D
0 → 7
F
J
transitions (J = 0–4) in the Eu3+ ion are dominant. For undoped crystals, the X-ray luminescence intensity of these bands increases by a factor of 15 with
a change in the temperature from 100 to 400 K. The possible mechanisms providing the observed temperature dependence of the
intensity and their relation to the specific features of energy transfer of electronic excitations in these crystals have
been discussed. It has been revealed that the glow curves for all the crystals under investigation exhibit the main complex
peak with the maximum at a temperature of 110–160 K and a number of weaker peaks with the composition and structure dependent
on the crystal type. The nature of shallow trapping centers responsible for the thermally stimulated luminescence in the range
below room temperature and their relation to defects in the lithium cation sublattice have been analyzed. 相似文献