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1.
Conclusion The specialized measuring setup described in the paper makes it possible to measure correctly and with reasonably high accuracy
the luminescence decay kinetics of dyes within the time range from 40 psec to 5 nsec upon excitation in the visible range
and at 1.064 μm.
The system is highly flexible, having at the same time reasonably large data storage memory, and is completely automated.
Such a system, undoubtedly, will be helpful for researchers working in the field of physics of laser media and dyes—passive
modulators for femtosecond laser systems.
The authors are grateful to M. V. Bondar for fruitful discussions and for help with the experiments.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 62, No. 1, pp. 128–134, January–February, 1995. 相似文献
2.
K. N. Korostik 《Journal of Applied Spectroscopy》1997,64(1):45-49
The effect of the shape of the excitation pulses on the magnitude of the frequency chirp in an injection laser is investigated.
It is established that as the degree of rectangularity of the pulses becomes higher, the frequency chirp increases. Simultaneous
consideration of the effect of residual charge in the active region of the laser, the delay of stimulated radiation, and the
frequency chirp indicates that in the case of high-velocity code modulation of an injection laser, in the latter an irregular
frequency chirp appears that can exert a noticeable influence on the distortion of code trains of pulses having a super-Gaussian
shape, when they propagate in media with a dispersion of 100 p.s./nm/km and above.
Belarusian State University, 4, F. Skorina Ave., Minsk, 220050, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii,
Vol. 64, No. 1, pp. 45–49, January–February, 1997. 相似文献
3.
The influence of changes in the refractive indices of the active medium and the loss modulator on the amplitude-detuning characteristic
of a CO2 laser was theoretically investigated. It is shown that at a comparatively great magnitude of sweeping the “instantaneous”
lasing frequency, the magnitude of the laser response increases not only in negative detunings, but also over a wide range
of positive detunings. The use of the procedure of changing the magnitude and sign of detuning as well as the range of sweeping
and the frequency of modulation makes it possible to realize various periodic and chaotic regimes of lasing, i.e., to exercise
control over the time and energy parameters of pulses over a very wide range.
B. I. Stepanov Institute of Physics of the Academy of Sciences of Belarus, 70, F. Skorina Ave., Minsk, 220072, Belarus. Translated
from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 3, pp. 318–324, May–June, 1997. 相似文献
4.
We investigated the effect of the mode composition (longitudinal and transverse modes) of laser radiation on the basic parameters
of the stroke pattern formed on a treated surface placed inside a laser cavity. We found that the contrast of the stroke pattern
formed by a laser beam with a complex set of longitudinal modes depends, in the first place, on the width of the laser radiation
spectrum and the laser cavity length and is virtually independent of the angle of rotation of the beam. In the region of small
rotation angles the broadening of strokes caused by the effect of transverse modes becomes predominant.
B. I. Stepanov Institute of Physics, Academy of Sciences of Belarus, 70, F. Skorina Ave., Minsk, 220072, Belarus. Translated
from Zhurnal Prikaladnoi Spektroskopii, Vol. 64, No. 1, pp. 50–54, January–February, 1997. 相似文献
5.
A. L. Blinov M. A. Borik G. E. Malashkevich I. V. Prusova A. P. Stupak 《Journal of Applied Spectroscopy》1998,65(1):84-87
We discovered and investigated sensitization of the luminescence of Tb3+ ions by Sn(II) oxocomplexes in highly activated alkali-free silicate glass. We show that the quantum yield of the luminescence
sensitization in this glass can be increased by UV irradiation. The possibility for the use of such glasses as luminescing
light filters for YAG-Nd laser quantrons is noted.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 65, No. 1, pp. 83–86, January–February, 1998. 相似文献
6.
A nonlinear device based on nonlinear total internal reflection is suggested which provides a more than ten-fold shortening
of the laser pulse and smooth variation of the pulse duration due to double reflection from the interface between transparent
and absorbing media. Results are presented for the shape and duration of the pulse components that have been reflected and
transmitted by the interface.
B. I. Stepanov Institute of Physics, Academy of Sciences of Belarus, 70, F. Skorina Ave., 220072, Minsk, Belarus. Translated
from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 3, pp. 325–328, May–June, 1997. 相似文献
7.
The nonlinear dynamics of a waveguide CO2 laser with combined periodic loss and pumping modulation is investigated theoretically and experimentally. The possibilities
of controlling time and energy parameters of the output radiation using the corresponding selection of the detuning of the
cavity's longitudinal mode from the center of the amplification line, the amplitude, and the frequency of loss modulation
are demonstrated. The observed asymmetric dependence of the lasing-radiation density on the detuning of the cavity frequency
is explained by the attendant modulation of the refractive index of the loss modulator.
To whom correspondence should be addressed.
B. I. Stepanov Institute of Physics, National Academy of Sciences of Belarus, 68, F. Skorina Ave., Minsk, 220072, Belarus.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 4, pp. 471–478, July–August, 1999. 相似文献
8.
9.
The effect of sub-nanosecond fluence fluctuations and triggering on time-resolved laser-induced incandescence (LII) from soot
has been studied using an injection-seeded pulsed Nd:YAG laser that produces a smooth laser temporal profile. Without injection
seeding, this multi-mode laser generates pulses with large intensity fluctuations with sub-nanosecond rise times. The experimental
results described here demonstrate that at fluences below 0.6 J/cm2 LII signals are insensitive to fluence fluctuations on nanosecond time scales. At fluences above 0.6 J/cm2 fluctuations in the laser profile cause the rising edge of the LII profile to move around in time relative to the center
of the laser pulse causing a broader average profile that shifts to earlier times. Such fluctuations also lead to a decrease
in the average LII temporal profile by up to 12% at a fluence of 3.5 J/cm2. A timing jitter on the trigger of the data acquisition, such as that produced by triggering on the laser Q-switch synchronization
pulse, has a negligible effect on the shape and temporal maximum of the LII signal. Additional jitter, however, considerably
reduces the peak of the LII temporal profiles at fluences as low as 0.15 J/cm2. Neither fast fluence fluctuations nor trigger jitter have a significant effect on gated LII signals, such as those used
to infer soot volume fraction. 相似文献
10.
Y. Gangrsky K. Marinova S. Zemlyanoi M. Avgoulea J. Billowes P. Campbell B. Cheal B. Tordoff M. Bissell D. H. Forest M. Gardner G. Tungate J. Huikari H. Penttilä J. Äystö 《Hyperfine Interactions》2006,171(1-3):209-215
Collinear laser spectroscopy experiments on the ScII transition 3d4s
3D2→3d4p
3F3 at λ ≈ 363.1 nm were performed on the 42–46Sc isotopic chain using an ion guide isotope separator with a cooler–buncher. Isotope and isomer shifts and hyperfine structures
of five ground states and two isomers were measured. Preliminary results on the nuclear moments and charge radii changes deduced
from these measurements are reported. 相似文献
11.
In this tutorial paper we compare the ab-initio calculations of electronic charge densities and related electric field gradients
in simple molecules like H2 as well as the triangular H3 with variable bond distance and bond angle using the Amsterdam Density Functional (ADF) code with calculations based on a
simple linear combination of hydrogen 1s-orbitals. In order to gain more insight into ADF – or other ab-initio – calculations it is rather useful to vary structural parameters. In addition to geometry optimisations we propose to vary
bond distances and bond angles over extended ranges in order to arrive at a better interpretation of the results. 相似文献
12.
A. G. Shvedko V. V. Ermolenkov S. G. Kruglik V. A. Orlovich 《Journal of Applied Spectroscopy》1999,66(5):841-850
A resonance-Raman-scattering multifrequency laser spectrometer operating in a wide spectral range (355–750 nm) and making
possible the recording of both stationary Raman spectra and spectra with a time resolution of up to 100 psec in the time interval
of 0–50 nsec has been developed. The spectrometer has been used with advantage for the study of the excited states of molecules
of metalloporphyrins in solutions and processes of interaction of model metalloporphyrins with DNA and DNA-modeling polynucleotides.
To whom correspondence should be addressed.
B. I. Stepanov Institute of Physics, National Academy of Sciences of Belarus 68, F. Skorina Ave., Minsk, 210072, Belarus.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 5, pp. 726–733, September–October, 1999. 相似文献
13.
A. P. Losev S. M. Bachilo D. I. Volkovich Yu. S. Avlasevich K. N. Solov’yov 《Journal of Applied Spectroscopy》1997,64(1):62-71
Photoinduced electron transfer (PET) in a Pd-porphyrin-quinone complex (Pd-P-Q) was investigated using the flash photolysis
method in microsecond and picosecond range and by luminescence. The investigations were performed for toluene solutions. Intramolecular
PETs in the lower excited singlet state (kCT=1.7·1010 sec−1) and in the triplet state (kCT=2.5·108sec−1) were observed. For a quantum yield of the triplet state that is close to 1 in Pd-porphyrin (Pd-P) this yield is equal to
0.4 in Pd-P-Q. This decrease is the result of PET in the excited state and, possibly, in an unrelaxed triplet state. Triplet
Pd-P-Q molecules were efficiently quenched by unexcited molecules, and this process is related to intermolecular charge transfer.
This electron transfer is likely to occur from the Pd-P protion of an excited molecule to the quinone protion of an unexcited
molecule in the collisional complex (Pd-P-Q)2. Charged radicals, formed once the collisional complex is transferred and separated, have a wide absorption band with a maximum
of about 960 nm. The average lifetime of the radicals was about 2 msec.
Institute of Molecular and Atomic Physics, Academy of Sciences of Belarus, 70, F. Skorina Ave., Minsk, 220072, Belarus. Translated
from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No 1 pp. 61–70, January–February, 1997. 相似文献
14.
We study the two-photon ionization of the hydrogen atom from its ground state by a three-color electromagnetic field consisting
of a superposition of an IR laser and two of its consecutive odd harmonics of order 2p−1 and 2p+1, withp a positive integer and constant relative phase difference. The ionization process due to the net absorption of the energy
2pħω (ω being the IR laser frequency) is considered. The influence of phase difference and helicity on the azimuthal angular distribution
of the ejected photoelectrons is illustrated in the case in which the two harmonics have identical polarizations. Phase effect
on the alignment of the differential ionization rate is also investigated. 相似文献
15.
R. Yang X. M. Li W. D. Yu X. J. Liu X. D. Gao Q. Wang L. D. Chen 《Applied Physics A: Materials Science & Processing》2009,97(1):85-90
A novel Ag–Al alloy electrode has been prepared on the La0.67Ca0.33MnO3 (LCMO) film grown by pulsed laser deposition, with the aim to improve its resistance-switching properties. Nonlinear, asymmetric,
and hysteretic current–voltage characteristics and reversible polarity-dependent switching properties are achieved in the
Ag–Al alloy/LCMO/Pt structure. Detailed current–voltage characteristics analysis indicates that the resistance-switching behavior
can be well explained by the mechanism of trap-controlled space charge limited conduction at the Ag–Al alloy/LCMO interface.
The LCMO film with an Ag–Al alloy top electrode exhibits much better resistance-switching properties than that with an Al
top electrode, including the shorter switching time and more stable switching process, demonstrating that the Ag–Al alloy
electrode is a promising electrode materials of manganite films for resistance random access memory applications. 相似文献
16.
S. G. Nedel’ko M. A. Krysyuk A. L. Apanasenko L. N. Lymarenko Z. T. Moroz 《Journal of Applied Spectroscopy》1997,64(1):55-61
Results of a study of the effect of γ-radiation on the spectral luminescence properties of cadmium tungstate crystals doped
with silver, bismuth, and molybdenum cations are presented. Spectral characteristics of the nondnnnoped crystals are briefly
described. Absorption and photo and X-ray luminescence spectra of the crystals taken before and after exposure to γ-radiation
(5.5·104 Gy) are compared. It is found that the spectral characteristics of the crystals doped with silver, bismuth, and molybdenum
cations do not change markedly after the exposure. The relation between the type of impurity-induced defects, individual characteristics
of the impurity cations, and the character of the effect of γ-radiation on the spectral luminescence properties of impure
crystals is analyzed (preliminarily).
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 1, pp. 55–60, January–February, 1997. 相似文献
17.
Interchromophore interactions and energy transfer in covalently bound porphyrin-chlorine heterodimer
V. N. Knyukshto É. I. Zen’kevich V. A. Kuz’mitskii V. I. Gael’ A. M. Shul’ga E. G. Levinson A. F. Mironov 《Journal of Applied Spectroscopy》1998,65(1):75-83
Energetis of interchromophore interactions in a covalently bound prophyrin-chlorine heterodimer (Por-O-Chl) is investigated
at temperatures from 77 to 293 K in solvents with differing polarity (toluene, tetrahydrofurane, and diethyl ether: petroleum
ester: isopropanole=5∶5∶2 mixture). We substantiate the conclusion that the strong quenching of fluoresence and phosphorescence
of the porphyrin fragments in both stable isomers of the Por-O-Chl heterodimer is induced not by the photoinduced charge transfer
but rather by efficient processes of singlet-singlet (probability FSS=1.3·1011 to 6.8°1010 sec−1) and triplet-triplet (probability FTT≥108 sec−1) radiationless electronic excitation transfer. It is shown that the S−S transfer takes place without quantum losses from
the thermodynamically equilibrated S1 state of the donor, and its dynamics and main regularities at temperatures from 77 to 293 K are described by the inductive
resonance theory without any additional asssumptions.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 65, No. 1, pp. 75–82, January–February, 1998. 相似文献
18.
M. K. Srivastava 《Pramana》2004,63(5):1053-1062
An approximate simple scaling law is obtained for asymmetric (e, 3e) process on helium-like ions for double ionization by fast electrons. It is based on the equation (Z
′3π) exp[-Z(r1 + r2)],Z′ = Z – (5/16) for ground state wave function of helium-like ions and Z′2 scaling of energies. The scaling law is found to work very well if the lower energy electron is ejected along the momentum
transfer direction and the other one is ejected in the opposite direction. It also works quite well if this electron is ejected
within about 90° of the momentum transfer direction with the other electron going in the opposite direction. The scaling law
becomes increasingly accurate as the target nuclear charge and the energy increase. 相似文献
19.
Summary This paper presents an investigation of the growth of a radially symmetrical ripple, superimposed on a Gaussian laser beam
in a collisionless magnetoplasma. The effect of the magnetic field and the intensity of the laser on the growth of the ripple
is presented in some detail. The effect of the presence of the ripple on the excitation of an electron plasma wave is also
investigated. Coupling of a weak plasma wave with the main laser beam is through the modified background density. The combined
effect of increased intensity of the laser beam and magnetic field is observed to suppress the growth of the ripple as well
as the excitation of the plasma wave.
The authors of this paper have agreed to not receive the proofs for correction. 相似文献
20.
We obtain an analytical expression for the pulse repetition period jitter of a diode-pumped solidstate laser with passive
Q-switching of the resonator. The possibilities of reducing the jitter of the pulse repetition period of generation are studied.
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 52, No. 4, pp. 337–342, April 2009. 相似文献