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1.
The efficient excitation to particular states has attracted much attention in both physics and chemistry[1-10]. The stimulated Raman adiabatic passage technique for pop- ulation transfer has been implemented with continuous or narrow band laser pulse (nanosecond time scale)[1], but the requirement for large pulse areas seems to advise against the use of short pulse lasers. However, the use of ultrashort laser pulse may have some distinct advan- tages, such as producing high energy frequencies,… 相似文献
2.
Extraordinary optical transmission through metal gratings with single and double grooved surfaces 下载免费PDF全文
We investigate the transmission properties of a normally
incident TM plane wave through metal films with periodic
parabolic-shaped grooves on single and double surfaces using the
finite-difference-time-domain method. Nearly zero transmission
efficiency is found at wavelengths corresponding to surface plasmon
excitation on a flat surface in the case where the single surface is
grooved. Meanwhile, resonant excitation of surface plasmon polariton
(SPP) Bloch modes leads to a strong transmission peak at slightly
larger wavelengths. When the grating is grooved on double surfaces,
the transmission enhancement can be dramatically improved due to the
resonant tunnelling between SPP Bloch modes. 相似文献
3.
Accurate determination of the absolute phase and temporal-pulse phase of few-cycle laser pulses 下载免费PDF全文
A Fourier analysis method is used to accurately determine not
only the absolute phase but also the temporal-pulse phase of an
isolated few-cycle (chirped) laser pulse. This method is
independent of the pulse shape and can fully characterize the
light wave even though only a few samples per optical cycle are
available. It paves the way for investigating the absolute
phase-dependent extreme nonlinear optics, and the evolutions of
the absolute phase and the temporal-pulse phase of few-cycle
laser pulses. 相似文献
4.
The optical properties of a five-level atomic system composed of a A-type four-level atomic and a tripod four-level atomic systems are investigated. It is found that the behaviors of electromagnetically induced transparency (EIT) and group velocity can be controlled by choosing appropriate parameters with the interacting dark resonances. In particular, when all the fields are on resonance, the slow light at the symmetric transparency windows with a much broader EIT width is obtained by tuning the intensity of the coupling field in comparison with its sub-system, which provides potential applications in quantum storage and retrieval of light. 相似文献
5.
利用量子干涉效应,在耦合腔系统中提出了一个相互作用自由的全光开关方案。在该方案中,两个腔通过光子隧穿效应耦合起来。当一个控制场与第二个腔中的原子相互作用时,信号光直接被第一个腔反射回去,因此信号光与控制光在原子-腔系统中没有发生直接耦合作用。本文方案即使在原子和腔之间不满足强耦合条件时也可以很好工作,从而放宽了实验条件下实现光开关的腔强耦合条件。 相似文献
6.
Global change in the dispersive behavior of terahertz (THz) plasmons on metal wires with wide radii ranging from 5 nm to 0.5 mm is systematically investigated. Through rigorous numerical calculations, we find that the dispersion of a metal wire with a radius of 5 nm increases by about 4-6 orders of magnitude compared with the case of a metallic wire with a radius of 0.5 mm. Zero-dispersion points appear when the frequency is lower than 3 THz, and the positions of the zero-dispersion points can shift with the frequency. Finally, we provide an explicit expression that agrees verv well with the numerical calculations. 相似文献
7.
Enhancement of Kerr nonlinearity with vanishing absorption in a tripod scheme 总被引:1,自引:0,他引:1 下载免费PDF全文
The giant enhancement of Kerr nonlinearity in a four-level tripod
type system is investigated theoretically. By tuning the value of
the Rabi frequency of the coherent control field, owing to the
double dark resonances, the giant-enhanced Kerr nonlinearity can be
achieved within the right transparency window. The influence of
Doppler broadening is also discussed. 相似文献
8.
Entanglement dynamics of two qubits coupled by Heisenberg XY interaction under a nonuniform magnetic field in a spin bath 下载免费PDF全文
This paper investigates the entanglement dynamics of a Heisenberg XY model for a two-spin system in the presence of a nonuniform magnetic field.The master equations and the concurrence evolution equations for the initial α state are derived and analysed.It is shown that for the symmetric initial α state,only the nonuniform field can play a role in entanglement dynamics while the uniform field and the bath will not play such a role.For the asymmetric α state,the nonuniform field leads to the beat pattern oscillation of the concurrence evolution.The inhomogeneity of the field can enhance the entanglement by suppressing the decoherence effects of both the spin-orbit interaction and the spin bath. 相似文献
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