High-intensity spatial-mode steerable frequency up-converter toward on-chip integration

Integrated photonic devices are essential for on-chip optical communication,optical-electronic systems,and quantum information sciences.To develop a high-fidelity interface between photonics in various frequency domains without disturbing their quantum properties,nonlinear frequency conversion,typically steered with the quadratic(χ2)process,should be considered.Furthermore,another degree of freedom in steering the spatial modes during theχ2 process,with unprecedent mode intensity is proposed here by modulating the lithium niobate(LN)waveguide-based inter-mode quasi-phasematching conditions with both temperature and wavelength parameters.Under high incident light intensities(25 and 27.8 dBm for the pump and the signal lights,respectively),mode conversion at the sum-frequency wavelength with sufficient high output power(−7–8 dBm)among the TM01,TM10,and TM00 modes is realized automatically with characterized broad temperature(ΔT≥8°C)and wavelength windows(Δλ≥1 nm),avoiding the previous efforts in carefully preparing the signal or pump modes.The results prove that high-intensity spatial modes can be prepared at arbitrary transparent wavelength of theχ2 media toward on-chip integration,which facilitates the development of chip-based communication and quantum information systems because spatial correlations can be applied to generate hyperentangled states and provide additional robustness in quantum error correction with the extended Hilbert space.

Study on Quality Standards of Laportea bulbifera(Sieb. et Zucc.) Wedd. in Yao’s Folk-medicine

[Objectives] This study was conducted to establish the quality control standards for Laportea bulbifera(Sieb. et Zucc.) Wedd. [Methods] Microscopic identification and thin layer chromatography were used to identify and determine the moisture, total ash and extract contents. [Results] According to the microscopic results, the stem transection is round and has five longitudinal edges at which the cell wall is obviously thickened. Bristles can be observed. A series of collenchyma cells are arranged closely inside the epidermis. There are several rows of parenchyma cells. The vascular bundles are of different sizes;and the ray part is wide, and at the junction of the ray and the cortex, there are often scattered secretory cells. The center is a broad medulla. The powder is brown. There are many starch grains. The bristles are unicelluar, and have warty protrusions and expanded base. The fibers are bundled, and the cells are large. The epidermal cells are in the shape of an elongated spindle, in a mosaic arrangement, and the cell wall is slightly thickened. From the thin layer identification chromatograms of tested L. bulbifera, it can be seen that spots were observed at the same positions as the control medicinal material, and the durability of the method was good. The extract content should not be less than 12.00% by hot extraction with water as solvent, and not be less than 3.00% by cold extraction with ethanol as solvent. The moisture content should not be more than 16.50%. The total ash content should not be more than 14.00%. The acid-insoluble ash content should not be more than 2.50%. [Conclusions] The microscopic identification results are reliable and can be used as the identification basis of L. bulbifera. The thin layer identification method and the test results can provide a basis for quality control of L. bulbifera.

Study on Quality Evaluation and Standards of the Zhuang Medicine Pandanus tectorius Soland.

[Objectives] This study was conducted to establish the quality control standards for Pandanus tectorius Soland.[Methods] Microscopic identification and thin layer chromatography were used to identify and determine the moisture,total ash and extract contents.[Results] The root transection is near round.The outmost side is velamen.There are nearly 10 columns of collenchyma tissue cells inside.In the cortex,there are a large number of fiber bundles scattered,and there are also large mucous cells scattered.The endodermis is distinct,and the cells are small and closely arranged.The pericycle is distinct and forms a ring.The pericycle fiber bundles are arranged in a radial shape by more than 40 bundles of phloem and xylem alternately.The leaf transection is V-shaped.The collenchyma lies under the epidermis.The spongy tissue has many calcium oxalate square crystal and needle crystals.The mucous cells contain calcium oxalate square crystal and needle crystals.The thin layer identification indicated that in the chromatogram of each test sample,spots of the same colors appeared at the positions corresponding to the chromatogram of the reference medicinal material,and the reproducibility was good.The moisture contents of the 10 batches of samples were all below 8.0%.The total ash was below 8.0%.The acid-insoluble ash was below 2.0%.With 50% ethanol as the solvent,the extract contents were all over 12.5%.[Conclusions] The microscopic identification results are reliable and can be used as the identification basis of P.tectorius.The thin layer identification method and the test results can provide a basis for quality control of P.tectorius.

Identification of Ethnic Medicine Polygonum capitatum by Thin Layer Chromatography

[Objectives]To establish a thin-layer chromatography identification method for the ethnic medicinal materials of Polygonum capitatum.[Methods]The thin layer chromatography(TLC)method was used to identify materials.[Results]The TLC identification showed that in the chromatogram of the test sample,there were spots of the same color in the corresponding position of the chromatogram of the reference medicinal material,and the reproducibility was good.[Conclusions]The TLC identification and the determination results of the inspection items can provide a basis for the quality control of the medicinal materials of P.capitatum.

Study on the Pharmacological Identification of Polygonum capitatum

[Objectives]This study was conducted to establish a microscopic identification method of Polygonum capitatum Buch.Ham.ex D.Don.[Methods]The cross sections were identified by microscopic identification.[Results]The stem cross section of P.capitatum is round-like,and shows pericyclic fibers forming a ring,strongly lignified,many vascular bundles,and a hollow pith part.There are many starch granules in the powder,and single granules are more common;and fibers are mostly bundled or scattered,lignified or non-lignified,and calcium oxalate cluster crystals are common.There are many pollen grains,obtuse triangular or round-like,and some of them have three germination apertures.They have fine thorn-like protrusions on the outer wall,the surface of which has reticulate carvings.[Conclusions]The results of microscopic identification are reliable and can be used as the basis for identification of P.capitatum.

Microscopic Identification of Zhuang Medicine Jatropha curcas L.

[Objective] This study was conducted to investigate the microscopic identification characteristics of Jatropha curcas .[Methods] Jatropha curcas was identified by microscopic identification. [Results] The stem bark of J. curcas has a thick phellem layer and broad cortex layer; and there are a great deal of dispersed laticifers and many fibers. The parenchymal cells contain clusters of calcium oxalate. In the powder, there are many clusters of calcium oxalate; the secreta is often dispersed; and the stomata are in parallel axle shape. Brown bodies can be seen commonly. [Conclusion] The results of the microscopic identification are reliable. These characteristics could provide an effective basis for the differentiation of this plant from other plants in the same genus and the establishment of its quality standard.

Passively Q-switched Tm/Ho composite laser

We explored Q-switching mechanism for the newly proposed Tm/Ho composite laser via developing a hybrid resonator for separating the intra-cavity Tm laser modulated by the saturable absorber(SA).With a Cr:ZnSe SA,successful passively Q-switching process with the maximum average output power of 474 mW and the shortest pulse width of 145 ns were obtained at the pulse repetition frequency of 7.14 kHz,where dual wavelength oscillation in both 2090 nm and 2097 nm was observed.This work provides an effective way for a direct laser diode(LD)pumped Q-switched Ho laser,which is compact and accessible.Furthermore,the current SA could be replaced by the 2D materials with broadband saturable absorption such as topological insulators or transition-metal dichalcogenides for seeking novel PQS lasers.

Hybrid laser precision engineering of transparent hard materials:challenges,solutions and applications

Laser has been demonstrated to be a mature and versatile tool that presents great flexibility and applicability for the precision engineering of a wide range of materials over other established micromachining techniques.Past decades have witnessed its rapid development and extensive applications ranging from scientific researches to industrial manufacturing.Transparent hard materials remain several major technical challenges for conventional laser processing techniques due to their high hardness,great brittleness,and low optical absorption.A variety of hybrid laser processing technologies,such as laser-induced plasma-assisted ablation,laser-induced backside wet etching,and etching assisted laser micromachining,have been developed to overcome these barriers by introducing additional medium assistance or combining different process steps.This article reviews the basic principles and characteristics of these hybrid technologies.How these technologies are used to precisely process transparent hard materials and their recent advancements are introduced.These hybrid technologies show remarkable benefits in terms of efficiency,accuracy,and quality for the fabrication of microstructures and functional devices on the surface of or inside the transparent hard substrates,thus enabling widespread applications in the fields of microelectronics,bio-medicine,photonics,and microfluidics.A summary and outlook of the hybrid laser technologies are also highlighted.

Validation of spectrum method for improving efficiency of continuous-wave ＆ Q-switched Tm-doped yttrium aluminum garnet laser

Tm3＋-doped 2-μm lasers benefit many applications such as atmospheric sensing, medical treatment, and spec- troscopy [1-3]. Therefore, in the past two decades, both continuous-wave （CW） and pulse operations have been widely researched in Tm3＋-doped bulk materials and fibers [4-7].

Controlled release of nerve growth factor and basic fibroblast growth factor combined with small-gap anastomosis enhances sciatic nerve regeneration

Objectives: Nerve regeneration after peripheral nerve injury is a slow process with a limited degree of functional recovery, resulting ina high disability rate. Thus, accelerating the rate of nerve regeneration and improving the degree of nerve repair is a clinical challenge. This study aimed to investigate the role of growth factor gel combined with small‐gap nerve anastomosis in the regeneration of sciatic nerve injury in rats. This was achieved by injecting nerve growth factor(NGF) and basic fibroblast growth factor(bF GF) gel into a silicon chamber that bridged the transection of the nerve. Methods: In 27 randomly chosen Sprague Dawley rats, a sharp blade was used to transect the right hind leg sciatic nerve. The rats were divided into 3 groups: in groups A and B, silicon tubes containing NGF and bF GF gel or saline, respectively, were used to bridge the nerve proximal and distal ends(3‐mm gap), and in group C, the nerve proximal and distal ends were directly sutured. Eight weeks after surgery, the sciatic nerve function index, neural electrophysiology, and muscle wet weight as well as histological, ultrastructural, and immunohistochemical parameters were evaluated.Results: The sciatic nerve function index, nerve conduction velocity, muscle wet weight,density of regenerated nerve fibers, and myelination in group A were better than those in group Bor C, but the sciatic nerve function index, muscle wet weight, and thickness of myelination in the 3 groups were not significantly different3(P > 0.05). There were no significant differences innerve conduction velocitybetween groups A and B(P > 0.05),but it was higher in both groups than that of group C(P < 0.05). The regenerated nerve fiber densityin the 3 groups showed significant differences(P < 0.05). Conclusions: Small‐gap nerve anastomosis can provide a good regenerative microenvironment for rat sciatic nerve regeneration, and the combined strategy of growth factor gel with small‐gap nerve anastomosis appears to havea superior effect on nerve repair.