Temporal soliton dynamics of synchronised ultrafast fibre lasers.

Synchronised ultrafast soliton lasers have attracted great research interest in recent decades. However, there is a lack of comprehensive understanding regarding the buildup mechanism of synchronised pulses. Here, we report a dynamic analysis of independent and synchronised solitons buildup mechanisms in synchronised ultrafast soliton lasers. The laser comprises an erbium-doped fibre cavity and a thulium-doped fibre cavity bridged with a common arm. Pulses operating at two different wavelengths formed in the cavities are synchronised by cross-phase modulation-induced soliton correlation in the common fibre arm. We find that the whole buildup process of the thulium-doped fibre laser successively undergoes five different stages: continuous wave, relaxation oscillation, quasi-mode-locking, continuous wave mode-locking and synchronised mode-locking. It is found that the starting time of the synchronised solitons is mainly determined by the meeting time of dual-color solitons. Our results will further deepen the understanding of dual-color synchronised lasers and enrich the study of complex nonlinear system dynamics.

Synchronized triple-wavelength fiber lasers at 1, 1.55, and 1.9†µm.

Synchronized lasers working at different wavelengths are of great significance for numerous applications, such as high-energy femtosecond pulse emission, Raman microscopy, and precise timing distribution. Here, we report synchronized triple-wavelength fiber lasers working at 1, 1.55, and 1.9 µm, respectively, by combining the coupling and injection configurations. The laser system consists of three fiber resonators gained by ytterbium-doped fiber, erbium-doped fiber, and thulium-doped fiber, respectively. Ultrafast optical pulses formed in these resonators are obtained by passive mode-locking with the use of a carbon-nanotube saturable absorber. A maximum cavity mismatch of ∼1.4 mm is reached by the synchronized triple-wavelength fiber lasers in the synchronization regime by finely tuning the variable optical delay lines incorporated in the fiber cavities. In addition, we investigate the synchronization characteristics of a non-polarization-maintaining fiber laser in an injection configuration. Our results provide a new, to the best of our knowledge, perspective on multi-color synchronized ultrafast lasers with broad spectral coverage, high compactness, and a tunable repetition rate.

Research progress on visual quality and complications after implantable collamer lens implantation / 国际眼科杂志(Guoji Yanke Zazhi)

Corneal refractive surgery and intraocular collamer lens(ICL)implantation are the mainstream refractive surgery methods at present. Many studies have proved that ICL implantation can effectively improve the postoperative visual acuity of patients. ICL implantation has gained favor among refractive doctors and patients because of its multiple advantages. Excellent postoperative visual acuity and visual quality are the key factors to improve patients' satisfaction. In order to evaluate the subjective and objective visual quality of patients after operation and avoid complications, this article reviews the visual quality and postoperative complications after ICL implantation.

Chirality logic gates.

The ever-growing demand for faster and more efficient data transfer and processing has brought optical computation strategies to the forefront of research in next-generation computing. Here, we report a universal computing approach with the chirality degree of freedom. By exploiting the crystal symmetry-enabled well-known chiral selection rules, we demonstrate the viability of the concept in bulk silica crystals and atomically thin semiconductors and create ultrafast (<100-fs) all-optical chirality logic gates (XNOR, NOR, AND, XOR, OR, and NAND) and a half adder. We also validate the unique advantages of chirality gates by realizing multiple gates with simultaneous operation in a single device and electrical control. Our first demonstrations of logic gates using chiral selection rules suggest that optical chirality could provide a powerful degree of freedom for future optical computing.

On-chip photonics and optoelectronics with a van der Waals material dielectric platform.

During the last few decades, photonic integrated circuits have increased dramatically, facilitating many high-performance applications, such as on-chip sensing, data processing, and inter-chip communications. The currently dominating material platforms (i.e., silicon, silicon nitride, lithium niobate, and indium phosphide), which have exhibited great application successes, however, suffer from their own disadvantages, such as the indirect bandgap of silicon for efficient light emission, and the compatibility challenges of indium phosphide with the silicon industry. Here, we report a new dielectric platform using nanostructured bulk van der Waals materials. On-chip light propagation, emission, and detection are demonstrated by taking advantage of different van der Waals materials. Low-loss passive waveguides with MoS2 and on-chip light sources and photodetectors with InSe have been realised. Our proof-of-concept demonstration of passive and active on-chip photonic components endorses van der Waals materials for offering a new dielectric platform with a large material-selection degree of freedom and unique properties toward close-to-atomic scale manufacture of on-chip photonic and optoelectronic devices.

Switchable Photoresponse Mechanisms Implemented in Single van der Waals Semiconductor/Metal Heterostructure.

van der Waals (vdW) heterostructures based on two-dimensional (2D) semiconducting materials have been extensively studied for functional applications, and most of the reported devices work with sole mechanism. The emerging metallic 2D materials provide us new options for building functional vdW heterostructures via rational band engineering design. Here, we investigate the vdW semiconductor/metal heterostructure built with 2D semiconducting InSe and metallic 1T-phase NbTe2, whose electron affinity χInSe and work function ΦNbTe2 almost exactly align. Electrical characterization verifies exceptional diode-like rectification ratio of >103 for the InSe/NbTe2 heterostructure device. Further photocurrent mappings reveal the switchable photoresponse mechanisms of this heterostructure or, in other words, the alternative roles that metallic NbTe2 plays. Specifically, this heterostructure device works in a photovoltaic manner under reverse bias, whereas it turns to phototransistor with InSe channel and NbTe2 electrode under high forward bias. The switchable photoresponse mechanisms originate from the band alignment at the interface, where the band bending could be readily adjusted by the bias voltage. In addition, a conceptual optoelectronic logic gate is proposed based on the exclusive working mechanisms. Finally, the photodetection performance of this heterostructure is represented by an ultrahigh responsivity of ∼84 A/W to 532 nm laser. Our results demonstrate the valuable application of 2D metals in functional devices, as well as the potential of implementing photovoltaic device and phototransistor with single vdW heterostructure.

Tunable Quantum Tunneling through a Graphene/Bi2Se3 Heterointerface for the Hybrid Photodetection Mechanism.

Graphene-based van der Waals heterostructures are promising building blocks for broadband photodetection because of the gapless nature of graphene. However, their performance is mostly limited by the inevitable trade-off between low dark current and photocurrent generation. Here, we demonstrate a hybrid photodetection mode based on the photogating effect coupled with the photovoltaic effect via tunable quantum tunneling through the unique graphene/Bi2Se3 heterointerface. The tunneling junction formed between the semimetallic graphene and the topologically insulating Bi2Se3 exhibits asymmetric rectifying and hysteretic current-voltage characteristics, which significantly suppresses the dark current and enhances the photocurrent. The photocurrent-to-dark current ratio increases by about a factor of 10 with the electrical tuning of tunneling resistance for efficient light detection covering the major photonic spectral band from the visible to the mid-infrared ranges. Our findings provide a novel concept of using tunable quantum tunneling for highly sensitive broadband photodetection in mixed-dimensional van der Waals heterostructures.

Scalable graphene electro-optical modulators for all-fibre pulsed lasers.

Recently, graphene electro-optical modulators have emerged as a viable alternative to the conventional modulators due to their broadband operation, ultrafast responsivity, small footprint, and low energy consumption. Here, we report scalable graphene electro-optical modulators for all-fibre pulsed laser applications. An actively Q-switched all-fibre laser is demonstrated with a scalable graphene electro-optical modulator for the first time, which is different from the previously reported work that typically implemented graphene electro-optical modulators in a free-space optical system. Our electrically modulated actively Q-switched fibre laser outputs at the centre wavelength of ∼1961.9 nm, the tunable repetition rate of 56.5 to 62.5 kHz, the maximum pulse energy of ∼80 nJ, and the signal-to-noise ratio of ∼46.6 dB. This work demonstrates that the scalable all-fibre integrated graphene electro-optical modulator approach is promising for producing pulsed fibre lasers at 2 µm with high performance and easy integration which are useful in various applications such as medical treatment, material processing, and spectroscopy.

Active synchronization and modulation of fiber lasers with a graphene electro-optic modulator.

We report the synchronization of two actively Q-switched fiber lasers operating at 1.5 µm and 2 µm with a shared broadband graphene electro-optic modulator. Two graphene monolayer sheets separated with a high-kHfO2 dielectric layer are configured to enable broadband light modulation. The graphene electro-optic modulator is shared by two optical fiber laser cavities (i.e., an erbium-doped fiber laser cavity and a thulium/holmium-codoped fiber laser cavity) to actively Q-switch the two lasers, resulting in stable synchronized pulses at 1.5 µm and 2 µm with a repetition rate ranging from 46 kHz to 56 kHz.

Wavelength and pulse duration tunable ultrafast fiber laser mode-locked with carbon nanotubes.

Ultrafast lasers with tunable parameters in wavelength and time domains are the choice of light source for various applications such as spectroscopy and communication. Here, we report a wavelength and pulse-duration tunable mode-locked Erbium doped fiber laser with single wall carbon nanotube-based saturable absorber. An intra-cavity tunable filter is employed to continuously tune the output wavelength for 34 nm (from 1525 nm to 1559 nm) and pulse duration from 545 fs to 6.1 ps, respectively. Our results provide a novel light source for various applications requiring variable wavelength or pulse duration.

Black phosphorus flakes covered microfiber for Q-switched ytterbium-doped fiber laser.

We demonstrate a passively Q-switched ytterbium-doped fiber laser based on black phosphorus (BP) flakes covered microfiber. The BP saturable absorber is fabricated by sandwiching a microfiber between two pieces of polydimethylsiloxane supported BP flakes film, which is prepared by the mechanical exfoliation method. In this case the BP flakes can be well protected from the action of air and moisture. By incorporating BP flakes covered microfiber into a ytterbium-doped ring fiber laser, stable and reliable Q-switched operation at 1064 nm can be realized via interaction between few-layers BP flakes and the evanescent field of the laser. The laser allows Q-switched pulse generation with a repetition rate in the range of 26-76 kHz and a pulse duration in the range of 5.5-2.0 µs, by varying the pump power from 38 mW to 100 mW.

946 nm Nd: YAG double Q-switched laser based on monolayer WSe2 saturable absorber.

In this paper, we report a 946nm double Q-switched laser side pumped by an 808-nm pulse laser diode (LD). A layered tungsten diselenide (WSe2) saturable absorber (SA) together with an MgO doped LiNbO3 electro-optic (EO) modulator is applied to double Q-switch the Nd: YAG laser, producing trains of nanosecond-duration pulses with 500 Hz repetition rate. Such WSe2 saturable absorbers are fabricated by chemical vapor deposition (CVD) in a hot wall chamber and then embedded into a resonant mirror. The achieved pulse energy of double Q-switched laser at 946 nm is approximately 2.63 mJ with 10.8 ns pulse width and the peak power is round 244 kW, corresponding to the beam quality factors of M2x = 3.846,M2y = 3.861. Monolayer WSe2 nanosheets applied in the experiment would be a promising SA for passive Q-switching operation.

Polarization and Thickness Dependent Absorption Properties of Black Phosphorus: New Saturable Absorber for Ultrafast Pulse Generation.

Black phosphorus (BP) has recently been rediscovered as a new and interesting two-dimensional material due to its unique electronic and optical properties. Here, we study the linear and nonlinear optical properties of BP flakes. We observe that both the linear and nonlinear optical properties are anisotropic and can be tuned by the film thickness in BP, completely different from other typical two-dimensional layered materials (e.g., graphene and the most studied transition metal dichalcogenides). We then use the nonlinear optical properties of BP for ultrafast (pulse duration down to ~786 fs in mode-locking) and large-energy (pulse energy up to >18 nJ in Q-switching) pulse generation in fiber lasers at the near-infrared telecommunication band ~1.5 µm. We observe that the output of our BP based pulsed lasers is linearly polarized (with a degree-of-polarization ~98% in mode-locking, >99% in Q-switching, respectively) due to the anisotropic optical property of BP. Our results underscore the relatively large optical nonlinearity of BP with unique polarization and thickness dependence, and its potential for polarized optical pulse generation, paving the way to BP based nonlinear and ultrafast photonic applications (e.g., ultrafast all-optical polarization switches/modulators, frequency converters etc.).

Broadband laser polarization control with aligned carbon nanotubes.

We introduce a simple approach to fabricate an aligned carbon nanotube (ACNT) device for broadband polarization control in fiber laser systems. The ACNT device was fabricated by pulling from as-fabricated vertically-aligned carbon nanotube arrays. Their anisotropic properties are confirmed with various microscopy techniques. The device was then integrated into fiber laser systems (at two technologically important wavelengths of 1 and 1.5 µm) for polarization control. We obtained a linearly-polarized light output with the maximum extinction ratio of ∼12 dB. The output polarization direction could be fully controlled by the ACNT alignment direction in both lasers. To the best of our knowledge, this is the first time that the ACNT device is applied to polarization control in laser systems. Our results exhibit that the ACNT device is a simple, low-cost, and broadband polarizer to control laser polarization dynamics, for various photonic applications (such as material processing, polarization diversity detection in communications etc.), where linear polarization control is necessary.

Curative effects of valsartan combined with Bailing capsule for the treatment of diabetic nephropathy / 中国基层医药

Objective To discuss the curative effects and clinical safety of using valsartan combined with Bailing capsule to treat diabetic nephropathy ( DN) .Methods In our hospital ,90 patients with diabetic nephropathy were chosen and divided into the two groups ( 45 cases in each group ):the control group treated with 80mg/d of valsartan and the observation group given bailing capsules 9g/d on basis of the control group .Before and after 16 weeks treatment,two groups′24h urine trace albumin excretion rate (UAER),potassium,serum creatinine (SCr), urea nitrogen ( BUN) ,total cholesterol ( TC) ,triglycerides ( TG) ,fasting plasma glucose ( FPG) and blood rheology changes were recorded and compared .Results After treatment the observation group′s high shear viscosity ,low shear viscosity,whole blood reductive viscosity and blood plasma viscosity all significantly decreased ( t=6.236,10.659, 12.509 and 7.269,all P0.05);No adverse reactions such as heart ,liver and kidney happened in the two groups .Conclusion Using valsartan in joint with Bailing capsule for the treatment of diabetic nephropathy ( DN) has distinct curative effects and no obvious adverse reactions ,which is worthy of clinical promotion .

The Clinical efficacy in the treatment of early diabetic nephropathy from rosuvastatin combined with benaze-pril / 中国基层医药

Objective To explore the clinical efficacy in the treatment of early diabetic nephropathy from ro-suvastatin combined with benazepril .Methods 107 patients of early diabetic nephropathy in our hospital were retro-spectively analyzed .On the basis of the conventional treatment of diabetes ,the control group were treated with benaze-pril;while the observation group were treated with rosuvastatin combined with benazepril .Before and after treatment , the improvement of the related indicators were observed , such as blood glucose ,lipids and renal function .The clinical efficacy were comprehensively evaluated .Results The level of the fasting blood glucose and 2-hour postprandial blood glucose of the observation group were lower than those of the control group , the difference was significant ( t=9.785,9.525,all P<0.05);the blood lipid levels such as TC ,TG and LDL-C in the observation group were signifi-cantly lower than those of the control group .But the levels of HDL-c was significantly increased , the difference was significant(t=9.938,10.283,10.475,9.782,allP<0.05);the indicators of renal function such as UAER ,Scr and BUN were significantly lower than those of the control group , the difference was significant ( t =9.938,12.341, 11.265,9.982,all P<0.05);The total effective rate of the observation group was 94.55%,significantly higher than the 76.92%of the control group, the difference was statistically significant (χ2 =10.120,P<0.05).Conclusion The effect of rosuvastatin combined with benazepril for the treatment of early diabetic nephropathy is very significant which is worthy applying in clinical practice .

Expression of glucose transporter protein 1 and desmin in reactive mesothelial hyperplasia and epithelioid malignant mesothelioma / 中华病理学杂志

<p><b>OBJECTIVE</b>To investigate the expression of glucose transporter protein 1 (GLUT-1) and desmin in benign and malignant mesothelial lesions, including reactive mesothelial hyperplasia (RMH), epithelioid malignant mesothelioma (EMM) and metastatic adenocarcinoma (MAC).</p><p><b>METHODS</b>One hundred and forty two pleural biopsy specimens were collected in this study, including 58 cases of RMH, 53 cases of EMM and 31 cases of MAC. Immunohistochemical EliVision method was performed to detect GLUT-1 and desmin expression.</p><p><b>RESULTS</b>The positive rates for GLUT-1 in RMH, EMM and MAC were 13.8% (8/58) , 81.1% (43/53) and 77.4% (24/31) , respectively, with statistically significant differences between RMH and others (both P < 0.01). The positive rates for desmin in RMH, EMM and MAC were 77.6% (45/58) , 9.4% (5/53) and 0 (0/31) , respectively, with statistically significant difference between RMH and others (both P < 0.01). The combined expression pattern of positive GLUT-1 and negative desmin was found in 1 (1.7%, 1/58) RMH cases, 41 (77.4%, 41/53) EMM cases and 24 (77.4%, 24/31) MAC cases, with statistically significant difference between RMH and others (both P < 0.01).</p><p><b>CONCLUSIONS</b>GLUT-1 and desmin may be used as immunohistochemical markers in separating RMH from EMM. Combined application of two antibodies may improve the specificity.</p>

Pulmonary capillary hemangiomatosis: a clinicopathologic analysis of 2 cases with review of literature / 中华病理学杂志

<p><b>OBJECTIVE</b>To investigate the clinicopathologic features of pulmonary capillary hemangiomatosis (PCH).</p><p><b>METHODS</b>The clinical and pathologic profiles of 2 PCH cases were evaluated. Immunohistochemical study (EnVision method) was performed on fixed tissues. The biologic behavior was analyzed with follow-up data.</p><p><b>RESULTS</b>The main presenting symptom was dyspnea. Chest radiography of the two cases depicted diffuse, ground-glass nodules, accompanied by enlarged central pulmonary arteries. Microscopically, the most distinctive feature was proliferation of capillary channels within pulmonary interstitium and alveolar walls, accompanied by muscularization of arterioles. Immunohistochemical study showed an abundance of mast cells in the lesion, and staining for platelet-derived growth factor receptor-beta (PDGFR-β) localized to vascular smooth muscles surrounding the proliferating capillaries and the mast cells. The index of Ki-67 was less than 1 percent and the p53 was negative.</p><p><b>CONCLUSIONS</b>PCH is a rare vascular proliferative disease of yang patients. Increased number of mast cell and the up-regulation of PDGFR-β may suggest mechanism for PCH. The clinical and radiologic diagnosis of PCH can be very difficult, and the histological examination is regarded as the most reliable means to establish the diagnosis. Pathologists should improve their knowledge on PCH.</p>

Pathologic diagnosis and clinical analysis of chronic extrinsic allergic alveolitis / 中华病理学杂志

<p><b>OBJECTIVE</b>To study the clinicopathologic features and diagnostic approach of chronic extrinsic allergic alveolitis (EAA).</p><p><b>METHODS</b>Seven cases of chronic EAA diagnosed by open lung biopsy or lung transplant were enrolled into the study. The clinical and pathologic features were analyzed and the literature was reviewed.</p><p><b>RESULTS</b>There were altogether 4 men and 3 women. The age of the patients ranged from 30 to 65 years (mean = 48 years). All cases represented chronic form and five cases diagnosed by open lung biopsy also showed features of recent aggravation, leading to hospitalization. Four cases had known history of exposure to inciting gases, pollens and pets, and only 2 cases were positive for allergens. High-resolution CT scan showed ground-glass attenuation and reticular pattern that often had a patchy distribution and central predominance. Bronchoalveolar lavage analysis showed marked lymphocytosis, with CD4(+)/CD8(+) ratio less than 1. Lung function test demonstrated a restrictive ventilatory defect, with decreased compliance, reduced diffusion capacity and high airway obstruction. Five cases had open lung biopsy performed and two cases had undergone lung transplantation. Pathologic examination showed bronchiolocentric cellular interstitial pneumonia, interstitial fibrosis, non-caseating epithelioid granulomas, epithelioid histiocytic infiltrate in the respiratory bronchioles and intraluminal budding fibrosis. The five cases with open lung biopsy performed also showed neutrophilic infiltrate in the alveoli. The two lung transplant cases were complicated by severe fibrotic changes.</p><p><b>CONCLUSIONS</b>Chronic EAA demonstrates characteristic pathologic features. Definitive diagnosis requires correlation with clinical and radiologic findings due to possible morphologic mimicry of other diffuse parenchymal lung diseases.</p>

Prevalence, awareness, treatment and control of hypertension in rural adult residents of Liaoning Province / 中华心血管病杂志

<p><b>OBJECTIVE</b>The objective of this study was to estimate the current status of prevalence, awareness, treatment and control rate of hypertension in adult residents living in rural area of Liaoning Province, North China.</p><p><b>METHODS</b>The screening was finished in 2008, probability proportional to size sampling method was used to select the representative sample. Blood pressure was measured in 153481 adults (aged > 35 yr), information on history of hypertension and use of antihypertensive medications was obtained by use of a standard questionnaire.</p><p><b>RESULTS</b>Overall, hypertension prevalence rate was 41.9%, the age-specific hypertension prevalence rate was 25.0%, 37.7%, 50.2%, and 64.9% in men and 22.1%, 41.1%, 56.6% and 70.2% in women age 35 to 44 years, 45 to 54 years, 55 to 64 years, and above 65 years, respectively. Among hypertensive patients, awareness rate was only 54.1%, 39.7% patients received antihypertensive medication and blood pressure control rate (< 140/90 mm Hg) was 6.9% in all participants and was 9.3% in treated hypertensive patients.</p><p><b>CONCLUSION</b>Our results indicates that hypertension prevalence is highly while awareness, treatment and control rate of hypertension was low in rural areas of northeast China. These results underscore the urgent need to develop comprehensive strategies to improve prevention, detection, and treatment of hypertension in rural population of Liaoning province.</p>