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1.
本文对光学玻璃的特殊色散机理进行了深入研究。研究认为,光学玻璃的特殊色散性能表征参数主要是相对部分色散偏离值ΔP_(g,F),ΔP_(g,F)绝对值越大,表明光学玻璃的特殊色散越大,越有利于消除光学系统的二级光谱。光学玻璃的特殊色散机理是由紫外和红外本征吸收引起。色散曲线中本征吸收峰的漂移和强弱将影响可见光区色散曲线斜率,进而使玻璃的相对部分色散偏离值变化。紫外本征吸收是由电子跃迁引起的;而红外本征吸收是由分子或分子集团振动造成的。开展特殊色散机理研究不仅可以深入揭示光学玻璃的"组分-结构-性能"关系规律,而且有助于开发特殊色散性能更优异的新型光学玻璃。 相似文献
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M. Sahrai A. Maleki R. Hemmati M. Mahmoudi 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2010,56(1):105-112
We investigate the dynamical behavior of the dispersion and the absorption
in a V-type three level atomic system. It is shown that in the presence of
decay-induced interference the probe dispersion and absorption are phase
dependent. We find that an incoherent pumping field provides an additional
control parameter for switching the group velocity of a light pulse. The
required switching times for switching the group velocity of a probe field
from subluminal to superluminal pulse propagation is then discussed. 相似文献
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Phase control of probe response in an open ladder type system with spontaneously generated coherence
Aiyun Li Hui Ma Xia Tan Yanling Yang Dianmin Tong Xijun Fan 《Optics Communications》2007,280(2):397-403
The control role of the relative phase between the probe and driving fields on the gain and dispersion in an open three-level ladder atomic system with incoherent pumping and spontaneously generated coherence is investigated. It is shown that by adjusting the value of the relative phase, the switching from lasing with inversion to lasing without inversion (LWI) can be realized; high index of the refraction with zero absorption can be achieved. It is also found that when the driving field is on resonance, the dispersion curve versus the probe detuning is very similar to the gain curve if the relative phase corresponding to the dispersion advances π/2 than that corresponding to the gain. LWI gain from the open system is obviously larger than that from corresponding closed system. When the incoherent pumping is absent, the open system can get LWI gain, moreover the gain is larger than that when the incoherent pumping presents for suitable value of the relative phase, but the corresponding closed system exhibits only absorption. In addition, manipulation effects of atomic exit and ratio of the injection rates on phase dependent gain are also analyzed. 相似文献
6.
M. Sahrai R. Etemadpour M. Mahmoudi 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2010,59(3):463-471
The dispersion and the absorption properties of a driven four-level Λ-type atomic system is investigated. It is found that the interaction of double-dark states lead to controllable group velocity
of the weak probe field by the intensity of driving field and the relative phase between applied fields. Moreover, the transient
dispersion, absorption and the group index are also discussed. The required switching time for switching the group velocity
of a weak probe field from subluminal to superluminal pulse propagation is then discussed. 相似文献
7.
Yu. M. Yevdokimov S. G. Skuridin V. I. Salyanov S. V. Semenov P. N. Sol’ev V. T. Valuev-Elliston F. V. Vereshchagin D. P. Chulkov O. N. Kompanets 《Optics and Spectroscopy》2017,122(2):194-201
We propose a version of the theory describing the circular dichroism spectra of cholesteric liquidcrystal dispersion particles of double-stranded DNA. The basis of the theory is the concept of absorption of electromagnetic waves by large molecular systems. The effect of physical parameters of dispersion particles on their circular dichroism is theoretically determined. It is experimentally demonstrated that circular dichroism can be used as a convenient tool for creating an optical analytical system for the determination of biologically active compounds that interact with DNA molecules. 相似文献
8.
A. V. Chaplik 《JETP Letters》2014,99(6):346-348
It has been shown that the Landau-damping-induced absorption of a modulated high-frequency electric field in a two-dimensional system of particles with a linear spectrum is absent up to the momentum of the field equal to the Fermi momentum of particles. This property qualitatively distinguishes such a system from the system of particles with a parabolic dispersion law, where the mentioned damping exists at any modulation period of an incident wave. 相似文献
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This paper investigates the control role of the relative phase between the probe and driving fields on the gain, dispersion and populations in an open A system with spontaneously generated coherence (SGC). It shows that by adjusting the value of the relative phase, a change from lasing with inversion to lasing without inversion can be realized; the values and frequency spectrum regions of the inversionless gain and dispersion can be obviously varied; high refractive index with zero absorption and electromagnetically induced transparency can be achieved. It is also found that when the driving field is resonant, the shapes of the dispersion and the gain curves versus the probe detuning are very similar if the relative phase of the dispersion lags π/2 than that of the gain, however for the off-resonant driving field the similarity will disappear; the gain, dispersion and populations are periodical functions of the relative phase, the modulation period is always 2π; the contribution of SGC to the inversionless gain and dispersion is much larger than that of the dynamically induced coherence. 相似文献
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V. I. Vysotskii M. V. Vysotskii 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2010,4(1):162-169
Peculiarities of induced radiation and absorption of hard electromagnetic radiation are considered on the basis of the channeling
of relativistic particles in crystals under the Vavilov—Cherenkov extreme condition. It is shown that the consistent inclusion
of quantum recoil in the relativistic region makes it possible to produce a number of anomalous effects having no analogs
in optics. In particular, it is predicted that it is possible to simultaneously cool the beam of fast particles during radiation
and absorption and to create a tandem laser for which successive radiation of quasicharacteristic-radiation quanta at the
normal and anomalous Doppler effect leads to the restoration of the initial state of the quantum system and to the multiple
repetition of the radiation cycle. It is shown that the main difficulties preventing these effects from being produced directly
in the X-and gamma-ray spectral regions are related to the necessity to use media with positive dispersion. It is considered
that such dispersion can be produced by changing the effective susceptibility of the medium in the case of radiation diffraction. 相似文献
12.
The properties of a five-level K-type system are investigated. With the controlling fields, the properties of the dispersion and absorption of the system are changed greatly. The system can produce anomalous dispersion regions with absorption and normal dispersion regions with absorption or transparency. Furthermore, the group velocity can be varied from subluminal to superluminal by varying the intensity of the controlling field and the probe detunings in principle. 相似文献
13.
在微波场闭合的三能级Lambda系统中计算了弱探测场的吸收和色散特性,发现闭合原子系统中的量子干涉导致弱探测场的吸收和色散特性依赖于施加场的相对位相。通过调节相对位相,获得了大的无反转增益和零吸收的高折射率。在三光子非共振的情况下,探测增益和吸收呈现随时间的振荡行为。 相似文献
14.
LI Jia-Hua LIU Ji-Bing XIE Xiao-Tao LUO Jin-Ming 《理论物理通讯》2006,46(1):130-134
Taking the density-dependent near dipole-dipole (NDD) interaction into consideration, we theoretically investigate the response of nonlinear absorption and dispersion in optically dense media of three-level atoms driven by a single-mode probe laser. The influence of the NDD effects on the absorption and dispersion spectra of the probe field is predicted via numerical calculations. It is shown that the NDD effects reduce gradually to transient absorption and amplification with the increase of the strengths of the NDD interaction, but do not change the steady-state behavior. Due to the presence of the NDD effects, steady-state absorption spectra exhibit asymmetric double-peak structure and overall shifts when a continuous-wave (cw) probe field is applied. However, frequency dispersion spectra are insensitive to them near the zero detuning. 相似文献
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X. J. Fan A. Y. Li S. F. Tian D. M. Tong S. Q. Gong Z. Z. Xu 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,42(3):483-488
We studied effects of the relative phase between the probe and driving fields on the absorption and dispersion properties
in an open three-level ladder system with spontaneously generated coherence but without incoherent pumping. It is shown that
by the phase controlling, switching from absorption to lasing without inversion (LWI) and enhancing remarkablely LWI
gain can be realized; large index of refraction with zero absorption and the
electromagnetically induced transparency can be obtained. We also find that
varying the atomic injection and exit rates has a considerable influence on
the phase dependent-absorption property of the probe field, existent of the
atomic injection and exit rates gives the necessary condition of the
realization of LWI, getting LWI is impossible in the corresponding closed
system without incoherent pumping. 相似文献
16.
The optical spectra of a five-level atom embedded in a photonic crystal are studied by considering the double-band photonic band gap reservoir with defect modes in the band gap. It is shown that some interesting phenomena such as absorption, transparency, normal or anomalous dispersion, and large amplification of a weak probe field can be observed by modulating system parameters. 相似文献
17.
Taking the density-dependent near dipole-dipole (NDD) interaction into consideration, we theoretically investigate the response of nonlinear absorption and dispersion in optically dense media of three-level atoms driven by a single-mode probe laser. The influence of the NDD effects on the absorption and dispersion spectra of the probe field is predicted via numerical calculations. It is shown that the NDD effects reduce gradually to transient absorption and amplification with the increase of the strengths of the NDD interaction, but do not change the steady-state behavior.Due to the presence of the NDD effects, steady-state absorption spectra exhibit asymmetric double-peak structure and overall shifts when a continuous-wave (cw) probe field is applied. However, frequency dispersion spectra are insensitive to them near the zero detuning. 相似文献
18.
Fritz Jähnig 《Zeitschrift für Physik A Hadrons and Nuclei》1973,258(3):199-208
The unified hydrodynamic theory for systems with a liquid crystalline phase is generalized to include a frequency dependence of the elastic and dissipative parameters of the system. Application is made to nematics for which the frequency dependent anisotropies of the velocity and absorption of sound are calculated. It is shown that the relaxation approximation for the dispersion leads to reasonable results. 相似文献
19.
M. Sahrai 《The European physical journal. Special topics》2008,160(1):383-390
This paper investigates the effects of the spontaneously generated coherence (SGC) and incoherent pumping field on the dynamical
behaviors of the dispersion and the absorption. Using a three-level Λ-type atomic medium, the influence of the relative phase
between the applied fields on the transient dispersion and absorption is discussed. It is shown that the phase dependence
of the dispersion and the absorption not only depend on the existence of SGC, but they depend on the existence of the incoherent
pumping field as well. We show that the medium can be used as an optical switch in which the propagation of the laser pulse
can be controlled by another laser field. 相似文献
20.
H. R. Hamedi 《JETP Letters》2014,100(1):44-54
The transient and steady-state dispersion and absorption properties of a three-subband asymmetric semiconductor quantum well system are investigated. In the steady-state regime, it is shown that by increasing the strength of Fano-interference as well as enhancement of energy splitting of two excited states the slope of dispersion changes from negative to positive which is corresponding to a switch between superluminal to subluminal light propagation. At the same time, the probe absorption reduces at telecommunication wavelength λ = 1550 nm. The influence of incoherent pumping fields on time-dependent susceptibility is then discussed. It is found that due to more transfer of population to the upper levels, increasing the rate of incoherent pump field leads to the reduction of probe absorption. In addition, it is realized that incoherent pumping has a major role in converting fast to slow propagation of light at long wavelength. We also introduce an extra controllability for the light pulse to be slow downed at Telecom wavelength just through the quantum interference arising from incoherent pumping fields. The obtained results may be practical in telecommunication applications. 相似文献