共查询到20条相似文献,搜索用时 78 毫秒
1.
A. P. Voitovich A. Ch. Izmailov O. E. Kostik V. V. Mashko 《Journal of Applied Spectroscopy》1999,66(1):48-54
A calculation of the selective losses of a spectrometer based on a broad-band laser with an anisotropic three-mirror ring
resonator containing a two-photon-absorbing atomic gas medium with a light-induced resonance anisotropy has been performed.
The conditions under which laser radiation power resonances appear in the output radiation spectrum and the contribution of
different factors to their formation have been revealed. Possible ways of obtaining information on the polarization effects
induced by a powerful light wave in a medium at the frequencies of two-quantum transitions were investigated.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 1, pp. 48–53, January–February, 1999. 相似文献
2.
Considering the unfixed background space-time and self-gravitational interaction, we review the Hawking radiation of the Kerr–Newman
black hole by Hamilton–Jacobi method. The result shows the tunneling probability is related to the change of Bekenstein–Hawking
entropy and the radiation spectrum deviates from the precisely thermal one, which is in accordance with Parikh and Wilczek’s
result and gives another method to study the Hawking radiation of the black hole. 相似文献
3.
A. A. Al-Rubaiee O. A. Gress K. S. Lokhtin Yu. V. Parfenov S. I. Sinegovskii 《Russian Physics Journal》2005,48(10):1004-1011
Spatial distribution of Čerenkov radiation of extensive air shower particles with energies 1013–1016 eV is simulated by the CORSIKA code for conditions and configuration of the Tunka-25 facility. Based on the calculated results,
sets of approximating functions are constructed for different primary particles and zenith angles. A comparison of the calculated
spatial distribution functions of Čerenkov light with the functions measured on the Tunka-25 facility demonstrates the feasibility
of identification of the particle initiating the shower and determination of its energy in the vicinity of the bend point
of the cosmic ray spectrum.
__________
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 7–13, October, 2005. 相似文献
4.
A. L. Gurskii I. I. Zholnerevich V. I. Kozlovskii I. I. Kulak E. V. Lutsenko A. I. Mit'kovets G. P. Yablonskii 《Journal of Applied Spectroscopy》1999,66(5):794-801
We present results of investigations of the directionality diagram and mode structure of radiation of semiconductor lasers
with electron pumping that have microrelief reflectors instead of a blind mirror and output mirrors, whose coefficient of
reflection depends on the wavelength and the angle of light propagation. Application of such mirrors allows one to narrow
the spectrum of output radiation of the lasers, simultaneously reducing the threshold and increasing the output power. The
discovered multilobe structure of the directionality diagrams is explained on the basis of geometrical optics. The possibility
of controlling the directionality of radiation depending on the spectral and angular characteristics of the output mirror
is shown.
Reported at the Second International Scientific and Technical Conference on Quantum Electronics, Minsk, November 23–25, 1998.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 5, pp. 092–697, Septemter–October, 1999. 相似文献
5.
It has been shown that the intensity of the electric dipole radiation from an atomic cluster with a certain arrangement of
atoms can be much larger (by a factor of 103–108) than the radiation intensity from an isolated atom owing to the interatomic interaction. This giant enhancement of light
is accompanied by a significant change in the radiation spectrum. 相似文献
6.
V. N. Belyi N. V. Kondratyuk A. A. Shagov A. G. Mashchenko 《Journal of Applied Spectroscopy》2000,67(2):364-368
Special features of the parameteric amplification of light in a BBO crystal in the pumping field of YAG:Nd laser radiation
(λ=1.064 μm) were investigated in the case in which the wavelength of the amplified signal of light lay within the eye-safe
region of the spectrum and the idle wavelength lay within the region of strong absorption. The correlation between the parametric
gain coefficient and the linear absorption coefficient of the crystal has been revealed.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 67, No. 2, pp. 263–266, March–April, 2000. 相似文献
7.
We have shown that brief exposure of sturgeon embryos (fertilized roe) in the organogenesis stage to low-intensity radiation
in the visible region of the spectrum can have a long-term effect on embryonic and post-embryonic development of the fish,
detectable 50 days after the irradiation procedure. The biological effects (size-weight characteristics and hardiness parameters
of the fish relative to unfavorable habitat conditions) induced by linearly polarized emission from a monochromatic laser
source (helium-neon laser, λ = 632.8 nm, Δλ ≈ 0.02 nm) and a quasi-monochromatic light-emitting diode (LED) source (maximum
in emission spectrum λ = 631 nm, Δ λ = 15 nm) are practically the same. Going to broadband linearly polarized radiation (λ
= 420–800 nm) is accompanied by a decrease in the biological effect.
From the results of studies of the effect on embryos from linearly polarized and unpolarized radiation from an LED source
and also the effect of linearly polarized, circularly polarized, and unpolarized radiation from a helium-neon laser, we concluded
that the type of polarization is of critical importance in realization of the biological effect of radiation. In this case,
the maximum stimulating effect (on the size×weight characteristics and the hardiness parameters for juvenile fish) is observed
on exposure to linearly polarized radiation; the photobiological effect induced in the same dose range by light with natural
polarization (i.e., unpolarized) is significantly less pronounced; the stimulating effect of circularly polarized radiation
occupies an intermediate position.
Based on the presented data and also on data obtained previously, we conclude that among the resonant and nonresonant photophysical
processes (orientational effect of light, effect of gradient forces, dipole-dipole interactions, thermooptic processes) capable
of inducing photobiological effects dependent on such laser-specific characteristics as polarization and coherence, the determining
influence in the processes studied in this work comes from the orientational effect of light and dipole×dipole interactions.
And the orientational effect can appear for anisotropic media with liquid-crystal type ordering (especially domains in membranes
and multiple-enzyme complexes) both under conditions when there is no resonant absorption and for weakly absorbing structures,
and can initiate a change in their conformations and accordingly their functional characteristics.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 6, pp. 843–858, November–December, 2008. 相似文献
8.
P. S. Parfenov A. P. Litvin A. V. Baranov A. V. Veniaminov E. V. Ushakova 《Journal of Applied Spectroscopy》2011,78(3):433-439
We present an analysis of methods for calibration of the spectral sensitivity of instruments in the near IR region of the
spectrum (0.90–2.05 μm), using as an example recording of the luminescence spectra of PbS semiconductor quantum dots using
a diffraction monochromator and an InGaAs photodiode as the detector. We show that when high-sensitivity detectors are employed
for calibration using the emission spectrum of an ideal black body, the problem of attenuation of the radiation flux is still
important. Instead of neutral density glass and mesh light filters for attenuation of the radiation, we propose using UFS
ultraviolet optical glasses (together with PS purple glasses), the maximum optical density of which is within the region of
maximum spectral sensitivity of InGaAs photodiodes. We give examples of spectral calibration, taking into account instrumental
characteristics and the effect of absorption by water vapor in the air, and also corrections of the luminescence spectra of
quantum dots. 相似文献
9.
The massive particles’ Hawking radiation from a spherically symmetric static black hole is investigated with Parikh-Wilczek
method, Hamilton–Jacobi method and Damour–Ruffini’s method. When energy conservation is considered, the same result can be
concluded that the radiation spectrum is not precisely thermal. The corrected spectrum is consistent to the underlying unitary
quantum theory, which can be used to explain the information loss paradox possibly.
相似文献
10.
Applying the Hamilton–Jacobi method, we investigate the Hawking radiation as tunneling from the non-stationary Vaidya–Bonner
black hole by considering the unfixed background space-time and self-gravitational interaction. The result shows the actual
radiation spectrum deviates from the purely thermal one and the tunneling rate is related not only to the change of Bekenstein–Hawking
entropy but also to the integral to the black hole mass and charge. This implies information loss is possible. 相似文献
11.
K. N. Korostik 《Journal of Applied Spectroscopy》1998,65(1):55-61
The influence of stimulated emission delay, dynamic shift in generation frequency, residual charge effect, timing jitter of
the radiation and excitation regime of an injection laser, as well as of dispersion in a fiber light guide on the data-internal
storage time in an electrooptical contour is investigated. It is found that the storage duration of an interval depends strongly
on the lifetime of nonequilibrium charge carriers, the simultaneous effect of a residual charge and jitter in an injection
laser, as well as on the dc bias current of the laser.
Belarusian State University, 4. F. Skorina Ave., Minsk, 220050, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii,
Vol. 65, No. 1, pp. 56–61, January–February, 1998. 相似文献
12.
S. A. Mikhnov 《Journal of Applied Spectroscopy》1999,66(6):994-998
It has been found that the F-band of optical absorption which is observed in ψ-irradiated NaF crystals consists of three overlapping
bands. The band at 345 nm of width 40 nm is independent of the impurity composition of the crystals; it disappears upon exposure
to radiation at 345 nm and appears again upon annealing at 460±15 K for 15 min. This band is correlatable in intensity with
the superfine structure of an EPR spectrum. The width (65–110 nm) and the spectral position (355–375 nm) of the second band
depend on the impurity composition of the crystal. The band of width 90–110 nm at 320–325 nm disappears upon annealing and
appears after exposure to light simultaneously with the disappearance of an EPR signal. It is established that the band at
345 nm is caused by quasimolecules based on fluorine atoms, that at 355–375 nm is triggered by F-centers with a different
impurity composition near the haloid vacancy, and the band at 320–325 nm owes its appearance to F-centers in a negatively
charged state (F′).
Institute of Molecular and Atomic Physics, National Academy of Sciences of Belarus, 70 F. Skorina Ave., Minsk, 220072, Belarus.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 6, pp. 849–853, November–December, 1999. 相似文献
13.
L. M. Vasilyak S. V. Kostyuchenko A. V. Krasnochub M. E. Kuz'menko 《Journal of Applied Spectroscopy》1998,65(2):319-321
The radiation of a pulsed-periodic discharge in CCl4 has been investigated. Its spectrum is found to differ considerably from the spectrum of the glow discharge. It is found
that ‖60% of the energy from the 215–650 nm region falls in the UV spectrum.
Moscow Physicotechnical Institute, 9, Institutskii Per., Dolgoprudnyi, 141701, Moscow Region, Russia. Translated from Zhurnal
Prikladnoi Spektroskopii, Vol. 65, No. 2, pp. 302–305, March–April, 1998. 相似文献
14.
Yu. I. Atrashevskii A. V. Sikorskii V. V. Sikorskii G. F. Stel’makh V. I. Shuplyak 《Journal of Applied Spectroscopy》1998,65(1):110-116
Angle distributions of the degree and azimuth of polarization of radiation scattered by individual leaves were measured. The
polarization characteristics of the reflected radiation were investigated at four radiation wavelengths (460, 550, 680, and
740 nm) and angles of exposure of leaves to light of 60–70°. The experiments were performed with leaves of maples (Acer platonoides)
at different stages of vegetation and withering. More than 1000 distributions of the spectral polarization characteristics
of the reflected radiation were obtained for maple leaves taken from regions with different ecological conditions during 1993–1995
It was established that the spectral polarization characteristics of the radiation scattered by a leaf markedly change with
the state of the leaf.
Belarusian State University, 4, F. Skorina Ave., Minsk, 220080, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii,
Vol. 65, No. 1, pp. 107–113, January–February, 1998. 相似文献
15.
The absorption and gain bands of a weak probe signal in the presence of the Bose-Einstein condensation of excitons, which
appears under nonequilibrium conditions in a field of coherent laser radiation, are considered. It is shown that the absorption
of light is caused by a quantum transition from the ground state of the crystal to the quasiexciton branch of the spectrum.
Amplification of the signal occurs as a result of transitions from the quasiexciton branch of the spectrum to the ground state
of the crystal.
Fiz. Tverd. Tela (St. Petersburg) 40, 924–927 (May 1998) 相似文献
16.
E. V. Derishev V. V. Kocharovsky Vl. V. Kocharovsky 《Radiophysics and Quantum Electronics》1997,40(1-2):93-102
The spectral evolution of the soft (≲1 MeV) gamma-ray radiation of neutron stars in a strong magnetic field (B ≳ 6·1012 G) is analyzed. It is shown that the radiation transfer equation for the photon splitting cascade has a one-parameter set
of self-similar solutions whose integral expansion is an efficient method for study of the general solution. An arbitrary
initial spectrum converges quickly to a self-similar solution provided that most of the radiation energy is concentrated in
the hard spectral range. We consider the possible observational consequences of the photon splitting, including the polarization
and softening of the output spectrum as well as the occurrence of a spectral break and condensation of all hard-energy radiation
near that break.
Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii,
radiofizika, Vol. 40, Nos. 1–2, pp. 146–160, January–February, 1997. 相似文献
17.
G. L. Bochek O. S. Deiev N. I. Maslov 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2012,6(2):356-361
The GEANT 4.9.2 software package is applied for the simulation of primary and Compton scattered bremsstrahlung spectra. The
possibility of restoring primary γ-radiation spectra with the energy 0.02–1200 MeV using Compton scattering on secondary scattering
targets is studied. The advantages of light targets using are demonstrated. An additional bremsstrahlung contribution from
e±-pairs is calculated for high-energy γ quanta; the influence of CXR on the form of scattered X-ray quantum spectra is estimated.
The spectra which have a multipeak structure are restored. For high-energy γ quanta there occurs significant spread of energies
in the Compton scattered radiation spectrum, which imposes stringent conditions on collimation and detector resolution capability.
The possibility of measuring the bremsstrahlung spectra from a primary target during high-angle Compton scattering is estimated. 相似文献
18.
V. A. Pustovarov B. V. Shul'gin É. I. Zinin A. Yu. Kuznetsov 《Russian Physics Journal》1996,39(11):1102-1113
Luminescence spectroscopy with subnanosecond time resolution is used to study features of nonequilibrium processes excited
in several broad-zone dielectrics (mainly inorganic scintillators) by pulses of synchrotron radiation (SR). When excitation
density exceeds a certain level, which is different for each material, there is an abrupt change in the kinetics of relaxation
of the nonequilibrium states. This change is accompanied by nonuniform broadening or shortwave shifting of the luminescence
spectrum and a drop in quantum light yield. The decay time for natural luminescence decreases by 1–3 orders, to nanoseconds,
and is independent of temperature within the range 80–450 K. The build-up stage disappears in the kinetics of luminescence
of Ce3+-centers and decay time is reduced by a factor of 2–4. Density effects are found to be independent of the conditions under
which the material is exposed to SR. A model is proposed in which density effects are related to nonradiative energy transfer
from the upper excited states of the luminescence centers to external quenching centers. The contribution of the space charge
induced by SR is also examined.
Ural State Technical University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 11, pp. 120–135, November,
1996. 相似文献
19.
The results of an investigation of continuous frequency tuning of a neodymium laser in the UV and VUV ranges are reported.
Generation of the sum frequency of second harmonic radiation and the radiation from a parametric light generator in the UV
region (338–366 nm) is achieved. The optimal conditions for tuning UV radiation in the range 113.5–117.0 nm in third-harmonic
generation processes in xenon and its mixtures with other gases are investigated. A third-harmonic generation efficiency of
∼5×10−4 and a tuning range >2600 cm−1 are obtained in the VUV range investigated.
Zh. Tekh. Fiz. 68, 82–89 (May 1998) 相似文献
20.
S. N. Ivanov E. Yu. Loktionov Yu. S. Protasov Yu. Yu. Protasov 《Journal of Applied Spectroscopy》2009,76(5):738-742
We describe an optical diagnostics module and the instrumental and methodological features of ultrahigh vacuum experiments
investigating the optical characteristics of condensed media in the short-wavelength (hv ~ 3.5–25 eV) range of the spectrum of probing synchrotron radiation. We give a brief presentation of the results of an experimental
determination of the spectral dependence of the luminescence quantum yield and the luminescence excitation spectrum of ablatable
polymer dielectrics on the Kurchatov synchrotron radiation source at values of the probing radiation power density (I
0 ~ 1012 photons/cm2∙sec) that are below threshold for extended surface vaporization and a surface temperature of the condensed targets equal
to 77–300 K. 相似文献