排序方式: 共有19条查询结果,搜索用时 46 毫秒
1.
A. S. Potapov P. A. Rodnyi S. B. Mikhrin I. R. Magunov 《Physics of the Solid State》2005,47(8):1436-1438
This work is a continuation of studies of the Pr3+ cascade emission in various matrices. The effect of the environment of the luminescence center on the mutual position of the lowest 5d and the 4f level 1S0 of Pr3+ is considered. PrF3 clustering in BaF2 is observed at a high praseodymium concentration. The promising potential of magnesium as a charge compensator for praseodymium in SrAlF5 is demonstrated. 相似文献
2.
E. Yu. Lundina Yu. M. Shernyakov M. V. Maksimov I. N. Kayander A. F. Tsatsul’nikov N. N. Ledentsov A. E. Zhukov N. A. Maleev S. S. Mikhrin V. M. Ustinov Zh. I. Alferov D. Bimberg 《Technical Physics》2003,48(1):131-132
Accelerated degradation testing of long-wavelength (>1.25 µm) quantum-dot lasers made on GaAs substrates is carried out at a fixed current of 1.7 A, initial optical output of about 0.3 W, and a heat sink temperature of 60°C. No signs of degradation are revealed after testing for 450 h. The test bed is not sealed, inert gas purging is not performed, and the laser faces are not passivated. 相似文献
3.
M.E. Sasin R.P. Seisyan M.A. Kaliteevski S. Brand R.A. Abram J.M. Chamberlain I.V. Iorsh I.A. Shelykh A.Yu. Egorov A.P. Vasil’ev V.S. Mikhrin A.V. Kavokin 《Superlattices and Microstructures》2010
We report on the first experimental observation of Tamm plasmon-polaritons (TPP) formed at the interface between a metal and a dielectric Bragg reflector (DBR). Contrary to conventional surface plasmons, TPPs have an in-plane wave vector less than the wave vector of light in vacuum, which allows for their direct optical excitation, and can be formed in both the TE and TM polarizations. The angular resolved reflectivity and transmission spectra of a GaAs/AlAs DBR covered by Au films of various thicknesses show the resonances associated with the TPP at low temperatures and at room temperature. The in-plane dispersion of TTPs is parabolic with an effective mass 4×10−5 of the free electron mass. 相似文献
4.
D. A. Firsov L. E. Vorobjev V. A. Shalygin V. Yu. Panevin A. N. Sofronov S. D. Ganichev S. N. Danilov A. V. Andrianov A. O. Zakhar’in A. E. Zhukov V. S. Mikhrin A. P. Vasil’ev 《Bulletin of the Russian Academy of Sciences: Physics》2008,72(2):246-248
Spontaneous emission of terahertz radiation from structures with GaAs/AlGaAs quantum wells in a longitudinal magnetic field has been studied. It is shown that some bands in the emission spectrum can be related to radiative electron transitions between resonant and localized impurity states, as well as to the transitions with participation of subband states. The temperature dependence of the equilibrium intraband absorption of terahertz radiation and its modulation in a longitudinal electric field in GaAs/AlGaAs quantum wells has been investigated. 相似文献
5.
P. A. Rodnyĭ I. V. Khodyuk E. I. Gorokhova S. B. Mikhrin P. Dorenbos 《Optics and Spectroscopy》2008,105(6):908-912
The spectral characteristics of ZnO:Ga and ZnO:Ga,N ceramics prepared by uniaxial hot pressing have been investigated. At room temperature, the edge (exciton) band at 3.12 eV dominates in the luminescence spectra of ZnO:Ga, while a wide luminescence band at 2.37 eV, which is likely to be due to zinc vacancies, is observed in the spectra of ZnO:Ga,N. Upon heating, the edge band maximum shifts to lower energies and the bandwidth increases. The extrapolated position of the edge-band maximum at zero temperature, E m (0) = 3.367 ± 0.005 eV, is in agreement with the data for thin zinc oxide films. The luminescence excitation spectra in the range from 3 to 6.5 eV are reported and the mechanism of energy transfer to excitons and luminescence centers is considered. 相似文献
6.
EP Sheretov VS Gurov MV Dubkov OV Korneeva 《Rapid communications in mass spectrometry : RCM》1999,13(16):1699-1702
In this article we compare the classical monopole mass filter of von Zahn and the monopole mass filter with a hyperbolic V-shaped electrode. The experimental results and those of computer simulation for both mass spectrometers are presented. We show that the replacement of a conventional 90 degrees V-shaped electrode by an electrode with a hyperbolic profile substantially improves the peak shape of any given mass, and increases the mass resolution by a factor of 3-4 and the abundance sensitivity by a factor of 100. The potential of high analytical performance combined with electroforming techniques for electrode manufacture indicate future practical uses of such instruments. Copyright 1999 John Wiley & Sons, Ltd. 相似文献
7.
The discovery of neutron rich isotopes of the lightest elements on the neutron drip line exhibiting a halo structure has opened
up new vistas in research activities. The novel structural features associated with the halo phenomena have been the subject
for extensive theoretical and experimental investigations in recent times. In this talk, I propose to present a broad overview
of the recent developments in this field, bringing out the striking features which show that a large number oflight nuclei
near the neutron drip line are characterized by a clear separation between a ‘normal’ core nucleus and a loosely bound low
density veil of neutrons. Specifically, the two neutron halos offer a natural premises, from a theoretical standpoint, to
employ three body techniques for studying their detailed structural properties. A considerable part of the talk will be devoted
to report and highlight the results on a number of light halo nuclei such as 11Li, 11Be, 19B and 22C on which we have been carrying out investigations employing a simple but realistic three body model. These three body systems
which have been termed as ‘Borromean’ (i.e while three body systems are bound, the corresponding binary subsystems on the
other hand are unbound) are characterized by large spacial extension and very low separation energy of the neutron. They are,
therefore, ideally suited for exploring the possibility of the existence of Efimov states in two neutron halo nuclei. We have
recently carried out the three body analyses to predict the possibility of the occurrence of such states on which experimental
work at various laboratories is underway. 相似文献
8.
NL Asfandiarov AI Fokin VG Lukin EP Nafikova GS Lomakin VS Fal'ko YV Chizhov 《Rapid communications in mass spectrometry : RCM》1999,13(12):1116-1123
A series of anthraquinone (C(14)O(2)H(8)) derivatives has been studied by means of electron capture negative ion mass spectrometry (ECNI-MS), photoelectron spectroscopy (PES), and AM1 quantum chemical calculations. Mean lifetimes of molecular negative ions M(-.) (MNI) have been measured. The mechanism of long-lived MNI formation in the epithermal energy region of incident electrons has been investigated. A simple model of a molecule (a spherical potential well with the repulsive centrifugal term) has been applied for the analysis of the energy dependence of cross sections at the first stage of the electron capture process. It has been shown that a temporary resonance of MNI at the energy approximately 0.5 eV corresponds to a shape resonance with lifetime 1-2.10(-13) s in the f-partial wave (l = 3) of the incident electron. The next resonant state of MNI at the energy approximately 1.7 eV has been associated with the electron excited Feshbach resonance (whose parent state is a triplet npi* transition). In all cases the initial electron state of the MNI relaxes into the ground state by means of a radiationless transition, and the final state of the MNI is a nuclear excited resonance with a lifetime measurable on the mass spectrometry timescale. Copyright 1999 John Wiley & Sons, Ltd. 相似文献
9.
10.
A. Yu. Nevsky U. Bressel I. Ernsting Ch. Eisele M. Okhapkin S. Schiller A. Gubenko D. Livshits S. Mikhrin I. Krestnikov A. Kovsh 《Applied physics. B, Lasers and optics》2008,92(4):501-507
We demonstrate a diode laser system which is suitable for high-resolution spectroscopy in the 1.2 μm and yellow spectral ranges.
It is based on a two-facet quantum dot chip in a Littrow-type external cavity configuration. The laser is tunable in the range
1125–1280 nm, with an output power of more than 200 mW, and exhibits a free-running line width of 200 kHz. Amplitude and frequency
noise were characterized, including the dependence of the frequency noise on the cavity length. Frequency stabilization to
a high-finesse reference cavity is demonstrated, whereby the line width was reduced to approx. 30 kHz. Using a femtosecond
frequency comb, the residual frequency instability was determined and found to be below 300 Hz on the time scales 1–300 s.
Yellow light (>3 mW) at 578 nm was generated by frequency doubling in an enhancement cavity containing a PPLN crystal. The
source has potential application for precision spectroscopy of ultra-cold Yb atoms and cold molecular hydrogen ions. 相似文献