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"Wang, Li-Gang"
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Controlling the Goos-Hänchen shift in a double prism structure using three-level Raman gain medium
We propose a scheme to control the Goos-Hänchen (GH) shift of TE and TM reflected light beams in a double-prism structure, where a three-level Raman gain medium is filling the gap between the two prisms. We find that it is possible to control the GH shift in this structure by externally adjusting the optical properties of the Raman gain atomic medium while the gap width between the two prisms is fixed. Inspired by recent successful implementation of the double-prism configuration with an air gap to measure the GH shift, we expected that our proposal to control the GH shift can be achieved experimentally and used in different potential applications of the GH shift.
Journal Article
Gouy and spatial-curvature-induced phase shifts of light in two-dimensional curved space
Gouy phase is the axial phase anomaly of converging light waves discovered over one century ago, and is so far widely studied in various systems. In this work, we have theoretically calculated Gouy phase of light beams in both paraxial and nonparaxial regime on two-dimensional curved surface by generalizing angular spectrum method. We find that curvature of surface will also introduce an extra phase shift, which is named as spatial curvature-induced (SCI) phase. The behaviors of both phase shifts are illustrated on two typical surfaces of revolution, circular truncated cone and spherical surface. Gouy phase evolves slower on surface with greater spatial curvature on circular truncated cone, which is however opposite on spherical surface, while SCI phase evolves faster with curvature on both surfaces. On circular truncated cone, both phase shifts approach to a limit value along propagation, which does not happen on spherical surface due to the existence of singularity on the pole. An interpretation is presented to explain this peculiar phenomenon. Finally we also provide the analytical expression of paraxial Gaussian beam on general SORs. By comparing the result with the exact method we find the analytical expression is valid under the approximation that beam waist and scale of surface are beyond order of wavelength. We expect this work will enhance the comprehension about the behavior of electromagnetic wave in curved space, and further contribute to the study of general relativity phenomena in laboratory.
Journal Article
Motion-induced energy shifts of a multilevel atom in a black-body radiation field
We investigate the influence of atomic uniform motion on radiative energy shifts of a multilevel atom when it interacts with black-body radiation. Our analysis reveals that the atomic energy shifts depend crucially on three factors: the temperature of black-body thermal radiation, atomic velocity, and atomic polarizability. In the low-temperature limit, the presence of atomic uniform motion always enhances the effect of the thermal field on the atomic energy shifts. However, in the high-temperature limit, the atomic uniform motion enhances the effect of the thermal field for an atom polarizable perpendicular to the atomic velocity but weakens it for an atom polarizable parallel to the atomic velocity. Our work indicates that the physical properties of atom–field coupling systems can in principle be regulated and controlled by the combined action of the thermal field and the atomic uniform motion.
Journal Article
Our experience with a modified prying-up technique for closed reduction of irreducible supracondylar humeral fractures
Satisfactory reduction of some displaced pediatric supracondylar humerus fractures is not achievable via closed reduction, thus necessitating open procedure, which increases the incidence of complications. Using percutaneous prying-up technique to assist closed reduction may reduce the requirement for transform to an open operation. We retrospectively reviewed displaced pediatric supracondylar humerus fractures treated by the same surgeon from September 2021 to January 2024,with 134 subjects meeting criteria for inclusion. These children were divided into two groups. In Group A(
n
= 61),the prying-up technique was used to assist with closed reduction of fractures. Group B(
n
= 73) included fractures treated with conventional manual traction. To balance group size,12 fractures from group A were randomly removed, leaving a final 61 patients in each group. Demographics, operative time, the rate of failed closed reduction, complications and radiographic results were analyzed. The operative time was significantly less in Group A as compared with Group B(mean difference, − 7.22; [95% confidence interval (CI), − 8.49 to − 5.94];
p
< 0.001). The rate of failed closed reduction were significantly lower in Group A as compared to Group B(2 of 61 vs. 10 of 61,
p
= 0.015).
However, we found no difference in terms of the radiographic results and complications between the two groups(
p
> 0.05). percutaneous prying-up technique significantly improves the efficiency of surgery and reduces rate of failed closed reduction of supracondylar humeral fractures in pediatric patients. Level III, retrospective comparative study.See Guidelines for Authors for a complete description of levels of evidence.
Journal Article
P68 RNA helicase promotes invasion of glioma cells through negatively regulating DUSP5
Gliomas are the most common central nervous system tumors. They show malignant characteristics indicating rapid proliferation and a high invasive capacity and are associated with a poor prognosis. In our previous study, p68 was overexpressed in glioma cells and correlated with both the degree of glioma differentiation and poor overall survival. Downregulating p68 significantly suppressed proliferation in glioma cells. Moreover, we found that the p68 gene promoted glioma cell growth by activating the nuclear factor‐κB signaling pathway by a downstream molecular mechanism that remains incompletely understood. In this study, we found that dual specificity phosphatase 5 (DUSP5) is a downstream target of p68, using microarray analysis, and that p68 negatively regulates DUSP5. Upregulating DUSP5 in stably expressing cell lines (U87 and LN‐229) suppressed proliferation, invasion, and migration in glioma cells in vitro, consistent with the downregulation of p68. Furthermore, upregulating DUSP5 inhibited ERK phosphorylation, whereas downregulating DUSP5 rescued the level of ERK phosphorylation, indicating that DUSP5 might negatively regulate ERK signaling. Additionally, we show that DUSP5 levels were lower in high‐grade glioma than in low‐grade glioma. These results suggest that the p68‐induced negative regulation of DUSP5 promoted invasion by glioma cells and mediated the activation of the ERK signaling pathway. We found that the function of the DUSP5 gene is to act as the downstream signaling pathway of p68 using global microarray gene expression analysis, and revealed that p68 negatively regulated the DUSP5 gene. Our discovery provides novel insight into the mode of negative regulation in cancer cells and represents a new facet in the complexities of p68 gene tumor‐promoting function.
Journal Article
A Novel Solid-State Thermal Rectifier Based On Reduced Graphene Oxide
Recently, manipulating heat transport by phononic devices has received significant attention, in which phonon – a heat pulse through lattice, is used to carry energy. In addition to heat control, the thermal devices might also have broad applications in the renewable energy engineering, such as thermoelectric energy harvesting. Elementary phononic devices such as diode, transistor and logic devices have been theoretically proposed. In this work, we experimentally create a macroscopic scale thermal rectifier based on reduced graphene oxide. Obvious thermal rectification ratio up to 1.21 under 12 K temperature bias has been observed. Moreover, this ratio can be enhanced further by increasing the asymmetric ratio. Collectively, our results raise the exciting prospect that the realization of macroscopic phononic device with large-area graphene based materials is technologically feasible, which may open up important applications in thermal circuits and thermal management.
Journal Article
Atom-field dynamics in curved spacetime
Some aspects of atom-field interactions in curved spacetime are reviewed. Of great interest are quantum radiative and entanglement processes arising out of Rindler and black hole spacetimes, which involve the role of Hawking−Unruh and dynamical Casimir effects. Most of the discussion surrounds the radiative part of interactions. For this, we specifically reassess the conventional understandings of atomic radiative transitions and energy level shifts in curved spacetime. We also briefly outline the status quo of entanglement dynamics study in curved spacetime, and highlight literature related to some novel insights, like entanglement harvesting. On one hand, the study of the role played by spacetime curvature in quantum radiative and informational phenomena has implications for fundamental physics, notably the gravity-quantum interface. In particular, one examines the viability of the Equivalence Principle, which is at the heart of Einstein's general theory of relativity. On the other hand, it can be instructive for manipulating quantum information and light propagation in arbitrary geometries. Some issues related to nonthermal effects of acceleration are also discussed.
Journal Article
Galactic-form spinning beams
Creating a structured transverse-intensity distribution that undergoes axial rotation during propagation while preserving its overall shape remains a major challenge, as achieving a stable, continuous, and substantial rotation across the entire beam cross-section has thus far proven elusive. Here, we introduce a class of intensity-rotating structured beams generated by diffracting a plane wave through a purely amplitude-based spiral-like structure composed of curved radial spokes, periodic in both radial and azimuthal directions. The diffraction patterns form concentric rings with petal-like intensity spots, whose number and spacing are set by the spoke count. Spoke curvature,
L
, induces relative azimuthal shifts between rings, producing a global rotation around the optical axis during propagation. Increasing
L
by an order of magnitude yields measurable rotations over 10
−2
of the initial propagation length, enabling faster rotations at shorter distances. Simultaneously, the beam divergence decreases, evolving toward a quasi-non-diffractive regime. The spots trace spiral trajectories reminiscent of galactic arms, inspiring the term galactic-form spinning beams. Phase analysis shows vortex-like azimuthal variations with topological charge equal to the spoke number. Numerical and experimental results confirm these dynamics, offering opportunities for structured-light applications.
Intensity-rotating beams are a class of structured beams that can potentially enable advanced optical manipulation techniques, as well as applications in free-space optical communication and high-resolution imaging, but their exploration has remained mostly theoretical. The authors demonstrate galactic-form spinning beams, i.e a stable, intensity-rotating beam whose dynamics and divergence can be precisely controlled.
Journal Article
Strong Coherent Light Amplification with Double Electromagnetically Induced Transparency Coherences
We experimentally demonstrate coherent amplification of probe field in a tripod-type atoms driven by strong coupling, signal and weak probe fields. We suppress linear and nonlinear atomic absorptions for resonant and near resonant probe via double electromagnetically induced transparency (DEIT). Combining these advantages of suppressed absorption along with temperature- or atomic-density-controlled transfer of population(ToP) between hyperfine ground states, we can induce near-resonant amplification of probe through stimulated Raman scattering(SRS) pumped by low-intensity signal field. The increased population difference of initial and final states of SRS due to increased ToP rate, together with reduced absorption at the second EIT window in an optically thick Cesium vapor, gives rise to highly effective coherent amplification.
Journal Article