Multi-longitudinal-mode lasers have been believed to be good candidates as pump sources for optical frequency conversion. However, we present a semiclassical model for the frequency conversion of optical signals with a multimode pump laser, which shows that fluctuations of the instantaneous pump power limit the conversion efficiency. In an experiment, we up-converted a 1.55-μm optical signal in a periodically poled lithium niobate waveguide using a multi-longitudinal-mode laser and observed a maximum conversion efficiency of 68%, in good agreement with our theoretical model. Compared to single-mode pumping, multimode pumping is not a suitable technique for attaining stable near-unity-efficiency frequency conversion. However, our results could find application in the characterization of the spectral or temporal structure of multi-longitudinal-mode lasers.

J. S. Pelc;G. L. Shentu;Q. Zhang;M. M. Fejer;建伟 潘

Physical Review A - Atomic, Molecular, and Optical Physics

2012-9-20

Single-photon light detection and ranging (LiDAR), offering single-photon sensitivity and picosecond time resolution, has been widely adopted for active imaging applications. Long-range active imaging is a great challenge, because the spatial resolution degrades significantly with the imaging range due to the diffraction limit of the optics, and only weak echo signal photons can return but mixed with a strong background noise. Here we propose and demonstrate a photon-efficient LiDAR approach that can achieve sub-Rayleigh resolution imaging over long ranges. This approach exploits fine sub-pixel scanning and a deconvolution algorithm tailored to this long-range application. Using this approach, we experimentally demonstrated active three-dimensional (3D) single-photon imaging by recognizing different postures of a mannequin model at a stand-off distance of 8.2 km in both daylight and night. The observed spatial (transversal) resolution is ∼5.5 cm at 8.2 km, which is about twice of the system’s resolution. This also beats the optical system’s Rayleigh criterion. The results are valuable for geosciences and target recognition over long ranges.

Zheng Ping Li;Xin Huang;Peng Yu Jiang;Yu Hong;Chao Yu;Yuan Cao;Jun Zhang;Feihu Xu;建伟 潘

Optics Express

2020-2-3

Thermal chemical treatments can effectively improve the surface properties of steels to resist wear, erosion, fretting, and oxidation. Among the various types of thermo-chemical treatment, pack cementation is most often employed for diffusing boron, aluminum, chromium, or silicon into the surface of steel. Pack cementation is superior to other thermo-chemical treatments in process simplicity and flexibility. However, like many other thermo-chemical treatments, conventional pack cementation (CPC) has the disadvantages of a high processing temperature and a long processing duration for obtaining a thick case. A novel approach is presented to enhance pack cementations by applying an alternating current field (ACF) on specimens and pack media. An adjustable 50 Hz alternating current power source was connected to a pair of parallel electrodes set in pack media. Investigations were conducted into the influences of the ACF on pack boriding, aluminizing, chromizing, and silicon-aluminizing. Cases' thicknesses, structures, phases, hardness distributions, and oxidation resistances were characterized with optical microscopy, X-ray diffraction, Vickers' hardness testing, and oxidation testing. These treatments can be carried out effectively at temperatures much lower than temperatures for CPC. The ACF can optimize cases' structures and phases as well as accelerate cases' growth. Brittle phases, such as iron boride and Al₅Fe₂, formed on a steel surface by CPC can be easily and economically avoided. The new technology can endow steels with properties that are much better than those provided by CPC. It is suggested that the ACF can enhance chemical reactions among pack agents by heating pack media and intensifying vibrations of active species. The formation, activity, and diffusion of active species containing required elements are promoted. The electromagnetic effect and the heating effect of the ACF increase vacancy concentrations in specimens, which greatly enhance diffusion in treated specimens.

Fei Xie;Shaoqiang Xu;建伟 潘

Materials Performance and Characterization

2018-8-20

Background. Light plays a key role in multiple plant developmental processes. It has been shown that root development is modulated by shoot-localized light signaling and requires shoot-derived transport of the plant hormone, auxin. However, the mechanism by which light regulates root development is not largely understood. In plants, the endogenous auxin, indole-3-acetic acid, is directionally transported by plasma-membrane (PM)-localized auxin influx and efflux carriers in transporting cells. Remarkably, the auxin efflux carrier PIN proteins exhibit asymmetric PM localization, determining the polarity of auxin transport. Similar to PM-resident receptors and transporters in animal and yeast cells, PIN proteins undergo constitutive cycling between the PM and endosomal compartments. Auxin plays multiple roles in PIN protein intracellular trafficking, inhibiting PIN2 endocytosis at some concentrations and promoting PIN2 degradation at others. However, how PIN proteins are turned over in plant cells is yet to be addressed. Methodology and Principle Findings. Using laser confocal scanning microscopy, and physiological and molecular genetic approaches, here, we show that in dark-grown seedlings, the PM localization of auxin efflux carrier PIN2 was largely reduced, and, in addition, PIN2 signal was detected in vacuolar compartments. This is in contrast to light-grown seedlings where PIN2 was predominantly PM-localized. In light-grown plants after shift to dark or to continuous red or far-red light, PIN2 also accumulated in vacuolar compartments. We show that PIN2 vacuolar targeting was derived from the PM via endocytic trafficking and inhibited by HY5-dependent light signaling. In addition, the ubiquitin 26S proteasome is involved in the process, since its inhibition by mutations in COP9 and a proteasome inhibitor MG132 impaired the process. Conclusions and Significance. Collectively, our data indicate that light plays an essential role in PIN2 intracellular trafficking, promoting PM-localization in the presence of light and, on the other hand, vacuolar targeting for protein degradation in the absense of light. Based on these results, we postulate that light regulation of root development is mediated at least in part by changes in the intracellular distribution of auxin efflux carriers, PIN proteins, in response to the light environment.

Ashverya Laxmi;建伟 潘;Mustafa Morsy;Rujin Chen

PLoS ONE

2008-1-30

Quantum memories are regarded as one of the fundamental building blocks of linear-optical quantum computation and long-distance quantum communication. A long-standing goal to realize scalable quantum information processing is to build a long-lived and efficient quantum memory. There have been significant efforts distributed towards this goal. However, either efficient but short-lived or long-lived but inefficient quantum memories have been demonstrated so far. Here we report a high-performance quantum memory in which long lifetime and high retrieval efficiency meet for the first time. By placing a ring cavity around an atomic ensemble, employing a pair of clock states, creating a long-wavelength spin wave and arranging the set-up in the gravitational direction, we realize a quantum memory with an intrinsic spin wave to photon conversion efficiency of 73(2)% together with a storage lifetime of 3.2(1)ms. This realization provides an essential tool towards scalable linear-optical quantum information processing.

Xiao Hui Bao;Andreas Reingruber;Peter Dietrich;Jun Rui;Alexander Dück;Thorsten Strassel;Li Li;Nai Le Liu;博 赵;建伟 潘

Nature Physics

2012-7

Einstein-Podolsky-Rosen (EPR) steering demonstrates that two parties share entanglement even if the measurement devices of one party are untrusted. Here, going beyond this bipartite concept, we develop a novel formalism to explore a large class of EPR steering from generic multipartite quantum systems of arbitrarily high dimensionality and degrees of freedom, such as graph states and hyperentangled systems. All of these quantum characteristics of genuine high-order EPR steering can be efficiently certified with few measurement settings in experiments. We faithfully demonstrate for the first time such generality by experimentally showing genuine four-partite EPR steering and applications to universal one-way quantum computing. Our formalism provides a new insight into the intermediate type of genuine multipartite Bell nonlocality and potential applications to quantum information tasks and experiments in the presence of untrusted measurement devices.

Che Ming Li;Kai Chen;Yueh Nan Chen;Qiang Zhang;宇翱 陈;建伟 潘

Physical Review Letters

2015-7-1

STOMATAL CYTOKINESIS DEFECTIVE1 (SCD1) encodes a putative Rab guanine nucleotide exchange factor that functions in membrane trafficking and is required for cytokinesis and cell expansion in Arabidopsis thaliana. Here, we show that the loss of SCD2 function disrupts cytokinesis and cell expansion and impairs fertility, phenotypes similar to those observed for scd1 mutants. Genetic and biochemical analyses showed that SCD1 function is dependent upon SCD2 and that together these proteins are required for plasma membrane internalization. Further specifying the role of these proteins in membrane trafficking, SCD1 and SCD2 proteins were found to be associated with isolated clathrin-coated vesicles and to colocalize with clathrin light chain at putative sites of endocytosis at the plasma membrane. Together, these data suggest that SCD1 and SCD2 function in clathrin-mediated membrane transport, including plasma membrane endocytosis, required for cytokinesis and cell expansion.

Colleen M. McMichael;Gregory D. Reynolds;Lisa M. Koch;Chao Wang;Nan Jiang;Jeanette Nadeau;Fred D. Sack;Max B. Gelderman;建伟 潘;Sebastian Y. Bednarek

Plant Cell

2013-10

Spotted leaf 5 (spl5), a lesion mimic mutant, was first identified in rice (Oryza sativa L.) japonica cv. Norin8 in 1978. This mutant exhibits spontaneous disease-like lesions in the absence of any pathogens and resistance to rice blast and bacterial blight; however, the target gene has not yet been isolated. In the present study, we employed a map-based cloning strategy to finely map the spl5 gene. In an initial mapping with 100 F₂ individuals (spl5/spl5) derived from a cross between the spl5 mutant and indica cv. 93-11, the spl5 gene was located in a 3.3-cM region on chromosome 7 using six simple sequence repeat (SSR) markers. In a high-resolution genetic mapping, two F₂ populations with 3,149 individuals (spl5/spl5) were derived from two crosses between spl5 mutant and two indica cvs. 93-11 and Zhefu802 and six sequence-tagged site (STS) markers were newly developed. Finally, the spl5 gene was mapped to a region of 0.048 cM between two markers SSR7 and RM7121. One BAC/PAC contig map covering these markers' loci and the spl5 gene was constructed through Pairwise BLAST analysis. Our bioinformatics analysis shows that the spl5 gene is located in the 80-kb region between two markers SSR7 and RM7121 with a high average ratio of physical to genetic distance (1.67 Mb/cM) and eighteen candidate genes. The analysis of these candidate genes indicates that the spl5 gene represents a novel class of regulators controlling cell death and resistance response in plants.

Xifeng Chen;建伟 潘;Jing Cheng;Guanghuai Jiang;Yang Jin;Zhimin Gu;Qian Qian;Wenxue Zhai;Bojun Ma

Molecular Breeding

2009-10

We derive a state-dependent error-disturbance trade-off based on a statistical distance in the sequential measurements of a pair of noncommutative observables and experimentally verify the relation with a photonic qubit system. We anticipate that this Letter may further stimulate the study on the quantum uncertainty principle and related applications in quantum measurements.

Ya Li Mao;Zhi Hao Ma;Rui Bo Jin;Qi Chao Sun;Shao Ming Fei;Qiang Zhang;Jingyun Fan;建伟 潘

Physical Review Letters

2019-3-8

Although exocytosis is critical for the proper trafficking of materials to the plasma membrane, relatively little is known about the mechanistic details of post-Golgi trafficking in plants. Here, we demonstrate that the DENN (Differentially Expressed in Normal and Neoplastic cells) domain protein STOMATAL CYTOKINESIS DEFECTIVE1 (SCD1) and SCD2 form a previously unknown protein complex, the SCD complex, that functionally interacts with subunits of the exocyst complex and the RabE1 family of GTPases in Arabidopsis thaliana. Consistent with a role in post-Golgi trafficking, scd1 and scd2 mutants display defects in exocytosis and recycling of PIN2-GFP. Perturbation of exocytosis using the small molecule Endosidin2 results in growth inhibition and PIN2-GFP trafficking defects in scd1 and scd2 mutants. In addition to the exocyst, the SCD complex binds in a nucleotide state-specific manner with Sec4p/Rab8-related RabE1 GTPases and overexpression of wild-type RabE1 rescues scd1 temperature-sensitive mutants. Furthermore, SCD1 colocalizes with the exocyst subunit, SEC15B, and RabE1 at the cell plate and in distinct punctae at or near the plasma membrane. Our findings reveal a mechanism for plant exocytosis, through the identification and characterization of a protein interaction network that includes the SCD complex, RabE1, and the exocyst.

Jonathan Russell Mayers;Tianwei Hu;Chao Wang;Jessica J. Cárdenas;Yuqi Tan;建伟 潘;Sebastian Y. Bednarek

Plant Cell

2017-10