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61.
The experiment of measuring the spin depolarized time and light storage time in a Rb vapor under different conditions is performed. Typically, these measurements are accomplished in three different containers: atoms in a bare glass cell, atoms in a buffer gas cell, and atoms in a tetracontane (C4oH82) coating cell. The increasing depolarization and storage times are observed in both the buffer gas cell and the tetracontane coating cell. In the latter case, a storage time greater than 400μs is obtained. 相似文献
62.
Due to many experimental data required and a lot of calculations involved, it is very complex and cumbersome to model prism-based liquid-refractive-index-measuring methods. We develop a new method of mathematical modelling for measuring refractive index of a liquid based upon the Fresnel formula and prism internal reflection at an incident angle less than the critical angle. With this method, only two different concentrations measurements for a kind of solution can lead to the determination of computational model. Measurements are performed to examine the validity of the theoretical model. Experimental results indicate the feasibility of the theoretical model with an error of 1%. The method is also capable of measuring even smaller changes in the optical refractive index of the material on a metal surface by the surface plasma resonance sensing techniques. 相似文献
63.
Entangled Radiation through an Atomic Reservoir Controlled by Coherent Population Trapping 下载免费PDF全文
We show that it is possible to generate Einstein-Podolsky-Rosen (EPR) entangled radiation using an atomic reservoir controlled by coherent population trapping. A beam of three-level atoms is initially prepared in nearcoherent population trapping (CPT) state and acts as a long-lived coherence-controlled reservoir. Four-wave mixing leads to amplification of cavity modes resonant with RabJ sidebands of the atomic dipole transitions. The cavity modes evolve Jnto an EPR state, whose degree of entanglement is controlled by the intensities and the frequencies of the driving fields. This scheme uses the long-lived CPT coherence and is robust against spontaneous emission of the atomic beam. At the same time, this scheme is implemented in a one-step procedure, not in a two-step procedure as was required in Phys. Rev. Lett. 98 (2007) 240401. 相似文献
64.
Using a representation of multichannel quantum defect theory in terms of a quantum Poincaré map for bound Rydberg molecules, we apply Jung's scattering map to derive a generalized quantum map, that includes the continuum. We show that this representation not only simplifies the understanding of the method, but moreover produces considerable numerical advantages. Finally we show under what circumstances the usual semi-classical approximations yield satisfactory results. In particular we see that singularities that cause problems in semi-classics are irrelevant to the quantum map. 相似文献
65.
66.
G. Huang C. Hang L. Deng 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2006,40(3):437-444
We study stable propagation of multiple shape-preserving optical
pulses in an inhomogeneously broadened multi-level atomic medium.
By analytically solving the Maxwell-Schr?dinger equations
governing the evolution of N coupled optical fields and atomic
amplitudes we show that N pulsed optical waves coupling to
(N+1)-levels can be automatically matched with the same soliton
waveform and identical yet very slow propagation velocity. Several
sets of coupled soliton solutions for two different (N+1)-level
models are given and their stability is studied by using a
numerical simulation. 相似文献
67.
J. H. Li X. X. Yang 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,53(4):449-454
We analyze hybrid absorptive-dispersive optical bistability (OB)
behavior via tunable Fano-type interference based on intersubband
transitions in asymmetric double quantum wells (QWs) driven
coherently by a probe laser field by means of a unidirectional
ring cavity. We show that OB can be controlled efficiently by
tuning the energy splitting of the two excited states (the
coupling strength of the tunnelling), the Fano-type interference,
and the frequency detuning. The influence of the electronic
cooperation parameter on the OB behavior is also discussed. This
investigation may be used for optimizing and controlling the
optical switching process in the QW solid-state system, which is
much more practical than that in atomic system because of its
flexible design and the controllable interference strength. 相似文献
68.
We investigate the dependences of the diffraction efficiency of the first order self-diffracted beam in bacteriorhodopsin (bR) films on the illumination time, the intensity and wavelength of the incident light. When the blue light (λ = 488 nm) and low intensity red light (λ = 632.8 nm) are incident on the bR film respectively,the diffraction efficiencies increase from zero to a stable value with the illumination time. When the green light (λ = 533 nm) and high-intensity red light illuminate the bR film respectively, the diffraction efficiencies increase from zero to the maximum and then decrease to a stable value with the illumination time. Rise and decay times are dependent on the intensity and wavelength of the incident light. The maximal diffraction efficiency of the red light is twice as high as that of the green light. The highest diffraction efficiency of 5.4% is obtained at 633nm.The diffraction efficiency change with the time for the green light is larger than that for the blue and red light. 相似文献
69.
Wei Bin Yan 《Optics Communications》2010,283(2):265-269
The frequency conversion and entanglement is studied via polariton technique. We analyze the effect of detuning on the efficiency of frequency conversion (EFC). The results show that by adjusting the second mode frequency, the EFC still can be achieved perfectly when the incoming photon is off-resonant. The effect of the spontaneous emission of the atoms on EFC is included. 相似文献
70.
C. Affolderbach A. Nagel S. Knappe C. Jung D. Wiedenmann R. Wynands 《Applied physics. B, Lasers and optics》2000,70(3):407-413
We have evaluated the suitability of a vertical-cavity surface-emitting laser diode (VCSEL) for spectroscopic applications.
Despite its low output power it is possible to observe narrow resonances in a saturated absorption spectroscopy experiment
on the cesium D
2 transition at 852 nm, limited in width by the laser linewidth of several tens of MHz. High modulation efficiency of the VCSEL
allows us to create modulation sidebands at 9.2 GHz frequency via direct modulation of the laser injection current. Using
the carrier and either one of the sidebands coherent population trapping (CPT) resonances in a buffered cesium vapor can be
prepared with linewidths below 130 Hz. With this very compact setup we have studied the dependence of CPT resonance position
and linewidth as a function of optical detuning and find evidence of the influence of the excited state hyperfine structure.
Received: 30 April 1999 / Revised version: 25 June 1999 / Published online: 30 November 1999 相似文献