arXiv subjects

Zhongping Chen

Publications and source records attributed to Zhongping Chen.

4 recordsLinked to original sources

arXiv2020

VIPER: Vectorial Interferometric Polarimeter for Electric-field Reconstruction

Comprehending the unique characteristics of structured ultrafast optical pulses is essential to the physics, applications and instrumentations of ultrafast lasers. However, full-vectrorial characterizations of the pulses remain challenging because of their multiple degrees of freedom. In this work, we implement and demonstrate the vectorial interferometric polarimeter for electric-field reconstruction (VIPER) which, for the first time, is able to precisely determine the specific three-dimensional E-field at every spatial-temporal coordinate throughout the entire detection region. This metrology provides a powerful tool for advanced ultrafast optics and paves the way for design optimization of ultrafast optics by providing the full information of the pulses, facilitating its applications in optical physics research, pump-probe spectroscopy and laser-based manufacturing.

physics.optics↗

arXiv2019

Integrated pulse scope for tunable generation and intrinsic characterization of structured femtosecond laser

Numerous techniques have been demonstrated for effective generation of orbital angular momentum-carrying radiation, but intracavity generation of continuously tunable pulses in the femtosecond regime remains challenging. Even if such a creation was realized, the generated pulses, like all pulses in reality, are complex and transitory objects that can only be comprehensively characterized via multidimensional spaces. An integrated lasing system that generates pulses while simultaneously quantifies them can achieve adaptive pulse tailoring. Here, we report a femtosecond pulse scope that unifies vector vortex mode-locked lasing and vectorial quantification. With intracavity-controlled Pancharatnam-Berry phase modulation, continuous and ergodic generation of spirally polarized states along a broadband higher-order Poincare sphere was realized. By intrinsically coupling a two-dimensional polarization-sensitive time-scanning interferometer to the laser, multidimensional spatiotemporal features of the pulse were further visualized. The proposed methodology paves the way for design optimization of ultrafast optics by integrating complex femtosecond pulse generation and structural customization, facilitating its applications in optical physics research and laser-based manufacturing.

physics.optics↗

arXiv2011

Nitrogen-induced Local Spin Polarization in Graphene on Cobalt

By means of first principles calculations we demonstrate an effective method to tailor the local spin configuration of graphene on Co(0001) surface through nitrogen doping. Two different site occupancies of the N impurities are discussed with the focus on structural, electronic and magnetic properties. N induces opposite local spin polarization at the two sites through Zener exchange-type hybridization with Co substrate. In addition, the induced spin polarization is energy dependent and controllable by electric field. Consequently this structure can be applied as a spin injection source in graphene based spintronics.

cond-mat.mtrl-sci↗

arXiv2004

Second harmonic optical coherence tomography

Second harmonic optical coherence tomography, which uses coherence gating of second-order nonlinear optical response of biological tissues for imaging, is described and demonstrated. Femtosecond laser pulses were used to excite second harmonic waves from collagen harvested from rat tail tendon and a reference nonlinear crystal. Second harmonic interference fringe signals were detected and used for image construction. Because of the strong dependence of second harmonic generation on molecular and tissue structures, this technique offers contrast and resolution enhancement to conventional optical coherence tomography.

physics.optics↗