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Guo Y.,Key Laboratory of Space Applied Physics and Chemistry | Yang D.,Northwestern Polytechnical University | Chang Y.,Key Laboratory of Space Applied Physics and Chemistry | Gao W.,Key Laboratory of Space Applied Physics and Chemistry
Optics Express | Year: 2014

The effect of asymmetry caused by oblique line-shaped laser ablation on the generation of ultrasonic waves in metal, especially the effect of transverse component of the ablation force source on the ultrasonic waves is analyzed. Due to the oblique force source, the displacements of shear wave increase obviously by the enhanced shear force, the energy concentration area of longitudinal wave deflects to the small range centered on the incident direction while that of shear wave is approximately perpendicular to incident direction. In addition, surface wave enhances in the direction of transverse power flow. Furthermore, some ultrasonic characteristics under vortex laser ablation condition are inferred. © 2014 Optical Society of America.


Liu S.,Northwestern Polytechnical University | Liu S.,Key Laboratory of Space Applied Physics and Chemistry | Zhang P.,Northwestern Polytechnical University | Zhang P.,Key Laboratory of Space Applied Physics and Chemistry | And 6 more authors.
Applied Physics B: Lasers and Optics | Year: 2010

A numerical approach of Brillouin zone (BZ) spectroscopy by employing coherent probe beams is proposed to visualize the Bragg reflection of complex photonic lattices. It is revealed that the Bragg reflections in non-Bravais lattices can be restrained or even canceled due to the composition of the multi-scatters. The BZ of other optical structures including quasi-crystal photonic lattices can be also visualized effectively. The results are in good agreement with the calculated band-gap structures and the conclusions came from the geometric structure factor. © Springer-Verlag 2010.


Jiang B.,Northwestern Polytechnical University | Jiang B.,Key Laboratory of Space Applied Physics and Chemistry | Zhao J.,Northwestern Polytechnical University | Zhao J.,Key Laboratory of Space Applied Physics and Chemistry | And 6 more authors.
Optics and Lasers in Engineering | Year: 2011

An optimized strain demodulation method based on dynamic double matched fiber Bragg grating (FBG) filtering driven by a piezoelectric transducer (PZT) is proposed and experimentally demonstrated. Using an optimized triangular waveform to drive PZT, the nonlinear effect is eliminated, and extraction and processing of the peak signals are more convenient. Furthermore, taking advantage of double matched-FBGs and strain amplification structure to demodulate the Bragg wavelength, the wavelength scanning range can be extended to 6.3 nm, so that a large-scale and high-precision strain measurement can be achieved. The experimental results show that in the strain range of 03800με, the linearity of the relationship between strain and scanning time-difference is greater than 99.8%, and the stability of repeated measurements is up to 99.5%. This demodulation method can be widely applied in the FBG measurement system. © 2010 Elsevier Ltd All rights reserved.


Jiang Y.,Northwestern Polytechnical University | Jiang Y.,Key Laboratory of Space Applied Physics and Chemistry | Zhao J.,Northwestern Polytechnical University | Zhao J.,Key Laboratory of Space Applied Physics and Chemistry | And 4 more authors.
Optics Communications | Year: 2010

A transverse pressure sensor with high-sensitivity based on a mechanically induced long-period fiber grating (MLPFG) and fiber loop ring-down technique is presented. When a MLPFG is spliced into a fiber loop, an extra loss is introduced, which leads to a decrease of the ring-down time. The results demonstrate that the difference between the reciprocals of the ring-down time with and without pressure increases exponentially with increasing the pressure in the range of 0-23.4 MPa. This sensor shows good repeatability, and the least detectable pressure is only 0.0068 MPa which is about 18 times less than detecting the output light intensity directly. © 2010 Elsevier B.V.


Guan P.,Northwestern Polytechnical University | Guan P.,Key Laboratory of Space Applied Physics and Chemistry | Hu X.L.,Northwestern Polytechnical University | Hu X.L.,Key Laboratory of Space Applied Physics and Chemistry | And 2 more authors.
Key Engineering Materials | Year: 2012

Erythromycin molecularly imprinted polymeric microspheres (EM-MIPMs) which have good shape and well-distributed size were prepared by suspension polymerization in aqueous phase, using EM as a template and methacrylic acid (MAA) as a functional monomer. The size of MIPMs is about 50.17 μm characterized by laser particle size analyzer and polarizing microscope. The interaction between the template and monomer, and selective binding performance were investigated by ultraviolet spectrum analysis, equilibrium binding experiments and Scatchard analysis. The results show tha t hydrogen bonding may contribute to the interaction between EM and MAA, EM-MIPMs demonstrated much higher adsorption capacity compared with the NMIPMs. It has also been found that there are two kinds of binding sites in EM-MIPMs and only one kind in NMIPMs. © (2012) Trans Tech Publications.


Lu S.,Northwestern Polytechnical University | Lu S.,Key Laboratory of Space Applied Physics and Chemistry | Zhao J.,Northwestern Polytechnical University | Zhao J.,Key Laboratory of Space Applied Physics and Chemistry | And 2 more authors.
Applied Optics | Year: 2010

In this paper, an asymmetric photonic crystal waveguide is proposed for flat band slow light transmission. Two structural parameters of one cladding layer of the waveguide are carefully adjusted. They are the refractive index of the liquid infiltrated in the cladding on one side and the radius of the air holes in the infiltrated cladding. In such an asymmetric waveguide, we can achieve a very flat band corresponding to high group index such as 29.4 and low dispersion (104ps2/km) for δω/ω= 1.46%. It is found that the value of ngδω/ω of the proposed waveguide can reach 0.429 and this waveguide can also yield a significant increase in the group index-bandwidth product ngω/ ω and improve the bandwidth. © 2010 Optical Society of America.


Jiang H.,Northwestern Polytechnical University | Jiang H.,Key Laboratory of Space Applied Physics and Chemistry | Zhao J.,Northwestern Polytechnical University | Zhao J.,Key Laboratory of Space Applied Physics and Chemistry | And 2 more authors.
Optics Communications | Year: 2012

This paper presents a method for recording and reconstructing high-quality digital color holographic images. The synthetic aperture technique is used to improve the resolution of the reconstructed image and also reduce the speckle size in the reconstruction plane. Subsequently, the multiple reference wave technique is used to suppress speckle noise in the reconstructed color holographic image by superposing speckle fields with different distributions. The final high-quality color holographic image is obtained due to the resolution improvement and speckle noise reduction achieved by the two techniques. Our method has potential applications in the digital color holographic displays. © 2012 Elsevier B.V. All rights reserved.


Di N.,Northwestern Polytechnical University | Zhao J.,Key Laboratory of Space Applied Physics and Chemistry
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2010

A Faraday-Fabry-Perot (FFP) cavity, composed of an Fabry-Perot (FP) cavity and a piece of Faraday magneto-optical material, is presented. The principle of FFP cavity and its polarization modulation effect are described by use of optical matrix analysis. The result shows that the Faraday rotation is able to be magnified by more than two orders of magnitude in resonant FFP cavity, while different elliptically polarized lights are obtained in non-resonant cavity. Furthermore two novel applications, that is, optical isolator based on passive FFP cavity (FOI) and Faraday-Zeeman dual-frequency laser (FZDL) based on active FFP cavity whose eigen modes operate as circularly polarized lights and whose frequency difference can be adjusted continuously by magnetic field, are introduced. The principles, typical parameters and performance characteristics are analyzed in both applications. © 2010 Copyright SPIE - The International Society for Optical Engineering.


Wang Y.L.,Key Laboratory of Space Applied Physics and Chemistry | Wang Y.L.,Northwestern Polytechnical University | Su K.H.,Key Laboratory of Space Applied Physics and Chemistry | Su K.H.,Northwestern Polytechnical University | And 2 more authors.
Advanced Materials Research | Year: 2012

The B, N, S, Si and P atoms doped single walled (5, 5) carbon nanotubes were studied by density functional theory B3LYP/3-21G (d) with the periodic boundary conditions. The ultra long tube models were calculated and the structures, energies and the band structures were obtained. The N, Si and S doped nanotubes have narrow energy gap with metal conductivity whereas B and P doped nanotubes have overlapped energy gaps with or semi-metal conductivity. © (2012) Trans Tech Publications.


Pan Z.-Y.,Key Laboratory of Space Applied Physics and Chemistry | Cao C.-D.,Key Laboratory of Space Applied Physics and Chemistry | Bai X.-J.,Key Laboratory of Space Applied Physics and Chemistry | Song R.-B.,Key Laboratory of Space Applied Physics and Chemistry | And 2 more authors.
Chinese Physics B | Year: 2013

Rare-earth compounds have been an attractive subject based on the unique electronic structures of the rare-earth elements. Novel ternary intermetallic compounds R2TX3 (R = rare-earth element or U, T = transition-metal element, X = Si, Ge, Ga, In) are a significant branch of this research field due to their complex and intriguing physical properties, such as magnetic order at low temperature, spin-glass behavior, Kondo effect, heavy fermion behavior, and so on. The unique physical properties of R 2TX3 compounds are related to distinctive electronic structures, crystal structures, microinteraction, and external environment. Most R2TX3 compounds crystallize in AlB2-type or derived AlB2-type structures and exhibit many similar properties. This paper gives a concise review of the structures and physical properties of these compounds. Spin glass, magnetic susceptibility, resistivity, and specific heat of R2TX3 compounds are discussed. © 2013 Chinese Physical Society and IOP Publishing Ltd.

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