Comment on “Focusing of high polarization order axially-symmetric polarized beams” [Chin.Opt.Lett.7,938 (2009)]

Some mathematical and conceptual errors contained in a recent letter [Chin.Opt.Lett.7,938 （2009）] are pointed out.

Properties of One-Dimensional Highly Polarized Fermi Gases

Using both the exact Bethe ansatz method and the variational method, we study properties of the one-dimensional Fermi polaron. We focus on the binding energy, effective mass, momentum distributions, Tan contact and correlation functions. As the attraction increases, the impurity is more tightly bound and correlated with the surrounding particles, and the size of formed polaron decreases. In addition, compared with the Bethe ansatz method, the variational method is totally qualified to study the one-dimensional Fermi polaron. The intrinsic reason is that the number of particle-hole excitations in a Fermi sea, caused by a single impurity, is always rather small. The variational method can be well extended to other impurity systems.

Backscattering from small-scale breaking wave turbulence structure generated by FLUENT

A breaking wave can exert a great influence on the electromagnetic（EM） scattering result from sea surfaces. In this paper, the process of small-scale wave breaking is simulated by the commercial computational fluid dynamics（CFD）software FLUENT, and the backscattering radar cross section（RCS） of the turbulence structure after breaking is calculated with the method of moments. The scattering results can reflect the turbulent intensities of the wave profiles and can indicate high polarization ratios at moderate incident angles, which should be attributed to the incoherent backscatter from surface disturbance of turbulence structure. Compared with the wave profile before breaking, the turbulence structure has no obvious geometrical characteristic of a plunging breaker, and no sea spikes are present at large incident angles either.In summary, the study of EM scattering from turbulence structure can provide a basis to explain the anomalies of EM scattering from sea surfaces and help us understand the scattering mechanism about the breaking wave more completely.

A high performance tunable optical filter based on cascaded polarization interference filter

A new kind of tunable optical filter is proposed for DWDM optical communication application. It is based on cascaded polarization interference filter (PIF). The period and bandpass width of each PIF are decided by its optical path difference between o-ray and e-ray (OPDOE). When their OPDOEs are proportionately designed, the tuning range and bandpass width depend on OPDOE in the first and the last PIF, respectively. The tuning range, bandpass width and crosstalk are independent each other. The crosstalk is related to the OPDOE ratios among PIFs and can be suppressed by designing the PIF's OPDOE. A set of OPDOE is suggested that are l1, 2 × l1, 22 ×l1, 23 ×l1, 24 ×l1, ..., 2N-4 × l1, 15 × 2N-7 ×l1, 10 × 2N-6 × l1 and 2N-2 ×l1 from the first to the last. This suggested OPDOEs can yield -50-dB crosstalk for any tuning range and bandpass width. The insert loss is less than 1 dB. As its loose alignment requirement, there is no limitation on cascaded PIF number. When 11 PIFs are cascaded, it can achieve 170-nm tuning range, -50-dB crosstalk, bandpass width applicable to 25-GHz channel spacing and 1 dB insert loss.

Highly polar CoP/Co_(2)P heterojunction composite as efficient cathode electrocatalyst for Li-air battery

In order to advance the commercialization of rechargeable Li-air batteries,it is of importance to explore cathode catalyst with efficient catalytic activity.Transition metal oxides have poor electrical conductivity,while cobalt phosphide has excellent electrical conductivity and large specific surface area.Nevertheless,its application in organic Li-air batteries has been much less studied,and the electrocatalytic activity desires to be further elevated.Here,CoP/Co_(2)P heterojunction composite with higher polarity was fabricated.The discharge product of high-polarity CoP/Co_(2)P had a new porous box-like morphology,which was easy to be decomposed and exposed more active sites.The highly polar CoP/Co_(2)P heterostructure composite had homogeneous pores,the synergistic effect existed between CoP and Co_(2)P,and the discharge product was porous box mixed with Li_(2)O_(2)and LiOH,which made CoP/Co_(2)P achieve high specific capacity of14632 m Ah/g and cycle stably 161 times when used as air electrode cathode catalyst.This work furnished a thought for the construction of cathode catalysts with efficient catalytic activity for Li-air batteries.

Manipulation of the overall polarization orientation in the focal volume of high numerical objectives

We propose an approach for tuning the three-dimensional polarization of a focusing subwavelength spot by a high numerical aperture objective. The incident beams are composed of a radially polarized beam, an azimuthally polarized beam, and a linearly polarized beam with three different weighting factors, respectively. A specially designed adjustable amplitude angular selector is also inserted at the back aperture of the objective for tuning the polarization azimuthally. It is shown that any desired overall polarization orientation can be obtained. We calculated the overall polarization orientation in the focal volume. It is found that the polar angle of the overall polarization orientation can be arbitrarily tuned by the combination of a radially polarized beam and a linearly polarized beam with different weighting factors, and the azimuthal angle can be tuned by rotating the orientation of the linearly polarized beam azimuthally.

Refractive index measurement of dielectric samples using highly focused radially polarized light(Invited Paper)

In this Letter, a refractive index measurement of a dielectric sample using highly focused radially polarized light is reported. Through imaging analysis of the optical field at the pupil plane of a high numerical aperture （NA） objective lens reflected by the sample under study, the Brewster angle is found. Employing a high NA objective lens allows the measurement of multiple angles of incidence from 0° to 64° in a single shot. The refractive index of the sample is estimated using the measured Brewster angle. The experimental results are compared with the theoretical images computed with the Fresnel theory, and a good agreement is obtained.

Tuning the fields focused by a high NA lens using spirally polarized beams(Invited Paper)

We show the power of spirally polarized doughnut beams as a tool for tuning the field distribution in the focus of a high numerical aperture （NA） lens. Different and relevant states of polarization as well as field distributions can be created by the simple turning of a λ/2 retardation wave plate placed in the excitation path of a micro- scope. The realization of such a versatile excitation source can provide an essential tool for nanotechnology investigations and biomedical experiments.

Online Postcolumn Indirect Detection for Determination of Ibandronate in Pharmaceutical Tablets by HPLC/DAD

Ibandronate sodium monohydrate is a highly polar aliphatic compound that belongs to the bisphosphonate class,a widely used bone resorption inhibitor.The aliphatic nature of ibandronate precludes direct photometric detection and its high polar-ity urged analysts to use ion-pairing agents in the mobile phase to promote retention in reversed-phase columns.In this work,a reversed-phase method for determination of ibandronate sodium monohydrate in pharmaceutical tablets is introduced by employing an online postcolumn ligand exchange reaction to enable photometric detection.The method offers for the first time the ability to separate the drug from its well-known impurities on conventional reversed-phase columns.The detection reac-tion depends on the ability of ibandronate and its degradation products to displace salicylate in the iron(III)salicylate complex,forming various colorless iron(III)complexes and showing a negative chromatographic signal for ibandronate and its degra-dants atλ_(max)=525 nm.The chromatographic separation was achieved using a Hypersil BDS C_(8) column(5μm particle size,150 mm×4.6 mm i.d.)and a mobile phase consisting of a mixture of aqueous formate buffer pH 3(pH 3,5 mM)and methanol in a ratio of 80:20%(v/v),delivered at a flow rate of 0.8 mL/min.The postcolumn iron(III)salicylate reagent was prepared at 250μM in aqueous formate buffer,delivered using a syringe pump at a flow rate of 0.5 mL/min.The proposed method was validated as per the guidelines of the International Conference on Harmonization Q2(R1)and was found linear over the range 40-120μg/mL(r=0.9995)with a limit of detection of 3.19μg/mL.Compared to currently reported methods,the proposed method is considerably simpler,faster,cheaper,and adequately sensitive and makes use of the most popular LC detectors.