Optimal sideband-squeezing in the resonance fluorescence of a two-level atom

The quantum fluctuation spectra of phase quadratures of the fluorescent light from a coherently driven two-level atom damping in a common vacuum is investigated. We find that by optimally choosing the Rabi frequency of the driving field, detuning between the atom and the driving field, and phase of the local oscillator the strong sideband squeezing in the spectrum of the optimal phase quadrature can be created and the degree of squeezing in the sidebands can reach about 56%.     

LaBaMnO薄膜的铁磁共振

用电子自旋共振实验研究La_0.65Ba_0.35MnO₃(LBMO)薄膜的磁性,从磁性膜的各向异性铁磁共振谱得到不同角度θ_h时的共振磁场B_r,求出样品的等效磁场B_eff及旅磁比γ,并通过样品的饱和磁化强度M_s,求出各向异性常数K.     

副品红共振光散射法测定脱氧核糖核酸

本文基于脱氧核糖核酸 (DNA)对有机染料副品红的共振光散射的增强效应 ,拟定了一种测定DNA的共振光散射法。在pH =0 5～ 1 5范围内 ,有机染料副品红于 35 5nm处的共振光散射强度被DNA强烈增强 ,且增强程度与DNA浓度呈线性关系 ,线性范围为 0 10～ 15 μg·mL- 1 ,检出限可达 36ng·mL- 1 。该方法简便、快速、具有较高的灵敏度和准确度 ,且线性范围较宽。将该方法用于混合样品中DNA的测定 ,结果令人满意。     

Revisiting Gouy phase

The aim of this paper is to highlight the added value of the generalized Gouy phase shift introduced by Siegman. Although suited for optical systems study, including those more complex than free space, we note that it did not meet the use that it deserves so far. The analysis of the whole of the ideas and analytical approaches associated to the important concept of the Gouy phase proves its effectiveness.

Usually, the resonance condition is systematically built on the basis of the equivalent empty cavity. Unfortunately, this approach does not cover some of the useful parameters of the real resonator. By means of the generalized Gouy phase and the self-consistent complex parameter q, we derive here a new approach for the calculation of the resonance condition for the real cavity. Moreover, the use of the generalized Gouy phase clearly simplifies the study of resonators, while making it possible to avoid the use of the Huygens’ Fresnel integral.     

Resonance light scattering technique used for biochemical and pharmaceutical analysis

By coupling and scanning simultaneously excitation and the emission monochromators of a common spectrofluorometer, enhanced resonance light scattering (RLS) signals could be obtained. The enhanced RLS signals could be used for designating bio-assemblies, aggregation species, and analytical purposes. Herein, we review the reports since the year of 2000 concerning the biochemical and pharmaceutical analysis with the RLS measurements, and discuss the possible developments of this technique.     

Resonance method for IR sensing

A highly sensitive method for infrared radiation detection based on thermal resonance in an active bolometer is set forth. An active bolometer is a self-oscillating system consisting of an IR-sensitive cell in a feedback circuit of an adjustable proportional controller. The analysis of an active bolometer autonomous (dark) dynamics reveals that with a generalized gain factor A variation the system evolves from relaxation type towards oscillating and self-oscillating type. When A=A_c, where A_c is a critical value of the generalized gain factor A, the steady state loses stability through self-excited thermal oscillations. The resonance in a system weakly perturbed by IR radiation modulated at self-oscillation frequency q₀[1+exp(iω_ct)] is considered. It is shown that in a small precritical vicinity =(A−A_c)/A_c of the gain factor the amplitude of forced thermal oscillations is proportional to q₀/A_c. The D^* calculation reveals that the detection power of a passive (A=0) bolometer increases with feedback introduction by a factor of 1/||. The detection powers of feasible versions of an active bolometer are compared.     

Approximation of photonuclear interaction cross-sections

Photonuclear interaction cross-sections from the GEANT4 database are approximated for all nuclei and all energies (from the hadron production threshold to about 40 TeV). The approximation methods in the giant-dipole resonance region, nucleon resonance region, and high-energy region are improved with respect to existing approximations. As an application of the approximation for photonuclear cross-sections, an improved method of calculating electronuclear cross-sections is developed. The interaction cross-section of virtual photons with nuclei at high Q² are approximated and a simple algorithm for describing the electronuclear reactions, including high-Q² scattering, is proposed. Received: 22 February 2002 / Accepted: 6 May 2002     

Determination of gamma-globulin at nanogram levels by its enhancement effect on the resonance light scattering of functionalized HgS nanoparticles

A novel assay of γ-globulin (γ-IgG) with a sensitivity at the nanogram level is proposed based on the measurement of enhanced resonance light-scattering (RLS) signals resulting from the interaction of functionalized nano-HgS with γ-globulin. At pH 5.03, the RLS signals of functionalized nano-HgS were greatly enhanced by γ-globulin in the region of 200-700 nm characterized by the peak around 362 nm. Linear relationship can be established between the enhanced RLS intensity and γ-globulin concentration in the range of 10-140 ng ml⁻¹. The limit of detection is 2.71 ng ml⁻¹. Based on this, a new direct quantitative determination method for γ-globulin in blood serum samples without separation of human serum albumin (HSA) is established. The contents of γ-IgG in blood serum samples were determined with recovery of 95.7-102.5% and R.S.D. of 1.6-2.4%. This method is proved to be very sensitive, rapid, simple and tolerance of most interfering substances.     

On the calculation of a limit for infinite systems from data on finite systems

We propose a mathematical model for the calculation of physical or chemical properties of infinite polymers, based on data for structurally closely related finite molecules. The modelling is phenomenological but permits a physical interpretation of the parameters involved in the equations. Received: 11 June 1996 / Accepted: 5 June 1997     

On the factors affecting the enhanced resonance light scattering signals of the interactions between proteins and multiply negatively charged chromophores using water blue as an example

Electrostatic interactions of proteins, including bovine serum albumin (BSA), human serum albumin (HSA), γ-globulin (γ-IgG), α-chymotrypsin (Chy), lysozyme (Lys) and cellulase (Cel), with multiply negatively charged chromophores were investigated based on the measurements of the enhanced resonance light scattering (RLS) signals. Using triply negatively charged water blue (WB) as an example, the factors were discussed that affect the enhanced resonance light scattering signals of the interactions between proteins and the negatively charged chromophores. It was found that the enhanced RLS signals with the maximum light scattering peak at 346.0 nm in these interacting systems are strongly dependent on the isoelectric points of proteins and show adverse linear relationships with increasing ionic strength depending on the positive charges of the inorganic metal ions used to control the ionic strength of the medium, sufficiently disclosing that the electrostatic attraction performs an important role in the combination of proteins with WB. Linear responses were discovered between the enhanced RLS signals and the protein molecular weights (M_w), displaying the dimensions of scattered particles formed by proteins and WB make a key contribution to the RLS enhancements. An empirical equation is proposed which possibly displays the factors affecting the enhanced RLS signals of the interactions between proteins with negatively charged chromophores.