Programmable multi-wavelength distributed feedback laser array integrated in a liquid crystal polymer waveguide.

Liquid crystal (LC) distributed feedback (DFB) lasers hold significant potential for integrated photonics applications. However, limitations in wavelength spacing for wavelength switching, device size, and compatibility with other technologies have impeded advancements of the LC DFB laser in integration and responsiveness. Herein, we propose a thin-film multi-wavelength DFB laser array utilizing high-resolution patterned programmable nematic LC polymers, enabling rapid switching with high-resolution wavelength spacing between wavelength division multiplexing channels while maintaining a stable single longitudinal mode (SLM) for each laser. The underlying physical mechanism involves modulating the effective refractive index of the DFB laser by varying the LC molecules' orientation angles between adjacent regions of the LC grating to achieve wavelength modulation. Additionally, a specialized LC waveguide design connects the DFB lasers, facilitating wavelength modulation as well as straight-line and bending propagation of the laser. Furthermore, the laser array demonstrates a relatively low energy threshold, facilitating its applications in high-integration scenarios.

Liquid Crystal Assembly for Ultra-dissymmetric Circularly Polarized Luminescence and Beyond.

Circularly polarized luminescence (CPL) is attracting much interest because it can carry extensive optical information. CPL shows left- or right-handedness and can be regarded as part of high-level visual perception to supply an extra dimension of information with regard to regular light. A key to meeting the needs for practical applications is to develop the emerging field of ultra-dissymmetric CPL. Chiral liquid crystal (LC) assemblies─otherwise referred to as cholesteric liquid crystals (CLCs)─are essentially organized helical superstructures with a highly ordered one-dimensional orientation, and distinctly superior to regular helical supramolecules. CLCs can achieve a perfect equilibrium of molecular short-range interaction and long-range orientational order, enabling molecule-scale chirality on a helical pitch and observable scale. LC assembly could be an ideal strategy for amplifying chirality, making it accessible to ultra-dissymmetric CPL. Herein, we focused on some basic but important issues regarding CPL: (i) How can CPL be created from chiral dyes? (ii) Is the chirality of luminescent dyes an essential factor for the generation of CPL? That is, can all chiral dyes emit CPL and vice versa? (iii) How can CPL be transferred within intermolecular systems, and what principles of CPL transmission should be followed? Given these queries and our work, in this Perspective we discuss the generation, transmission, and modulation of CPL with chiral LC assembly, aiming to design and build up novel chiroptical materials. Recent applications of CPL-active LC microstructures in three-dimensional displays, circularly polarized lasers, and asymmetric catalysis are also discussed.

Collecting, transporting and sorting micro-particles via the optical slings generated by a liquid crystal q(φ)-plate.

We disclose a transporting/collecting optical sling generated by a liquid crystal geometric phase optical element with spatial variant topological charge, which shows the intriguing repelling/indrawing effect on the micro-particle along the spiral orbit. Two proof-of-concept prototypes, i.e., an optical conveyor and a particle collector, are demonstrated. Based on the distinct dynamic characteristics of the micro-particles in different sizes, we conceptually propose a design for particle sorting. Thus, our proposed method to generate a spiral optical sling with spatial variant orbital angular momentum for on-demand collecting, transporting and sorting micro-particles is substantiated, which can find extensive applications in bio-medicine, micro-biology, etc.

Entanglement generation and steering implementation in a double-cavity-magnon hybrid system.

We demonstrate a scheme for the generation of bipartite and tripartite entanglement, as well as he implementation of stable and controllable long-distance one-way and asymmetric two-way steering in a cavity-magnon hybrid system. This system consists of a magnon mode and two coupled microwave cavities. The first cavity is driven by a flux-driven Josephson parametric amplifier, which generates squeezed vacuum fields, and is coupled to the other cavity through optical tunneling interaction. The second cavity and magnon mode are coupled through magnetic dipole interaction. We find that under weak coupling between the two cavities, and strong coupling between the second cavity and magnon mode, remote controllable one-way steering and tripartite entanglement can be achieved. Our scheme may have potential applications in quantum information.

Entanglement enhancement and EPR steering based on a PT-symmetric-like cavity-opto-magnomechanical hybrid system.

We investigate the enhancement of entanglement and EPR steering in a parity-time(PT-) symmetric-like cavity-opto-magnomechanical system. The system consists of an optical cavity, a magnon mode in a ferromagnetic crystal, a phonon mode, and a microwave cavity. Our findings demonstrate that microwave-cavity gain significantly boosts distant quantum entanglement and greatly improves the robustness of bipartite entanglement against environment temperature. Additionally, we observe an enhancement of tripartite entanglement within the system and uncover the phenomenon of entanglement transfer. Notably, we also achieve one-way steering and two-way asymmetric steering in the system. This study offers insights into the integration of traditional optomechanics and cavity magnomechanics, presenting a novel approach to manipulate asymmetric quantum steering between two distant macroscopic objects. The implications of our research extend to the fields of quantum state preparation and quantum information.

Deflecting and routing nematicons via orientation programmable liquid crystal array.

By designing a liquid crystal cell with comb electrode structure, the alignment modulation of nematic liquid crystal in the cell can be realized after the electric field is applied. In different orientation regions, the incident laser beam can deflect at different angles. At the same time, by changing the incident angle of the laser beam, the reflection modulation of the laser beam on the interface of the liquid crystal molecular orientation change can be realized. Based on the above discussion, we then demonstrate the modulation of liquid crystal molecular orientation arrays on nematicon pairs. In different orientation regions of liquid crystal molecules, nematicon pairs can exhibit various combinations of deflections, and these deflection angles are modulable under external fields. Deflection and modulation of nematicon pairs have potential applications in optical routing and optical communication.

A simple polarimetric measurement based on a computational algorithm.

A simple and compact polarimeter comprising two electrically controlled liquid-crystal variable retarders (LCVRs) and a linear polarizer is demonstrated, which is enabled by analyzing the intensity variation of the modulated output light based on a computational algorithm. A proof-of-concept prototype is presented, which is mounted onto a power meter or a CMOS camera for the intensity data collection. The polarimetric measurement for the spatial variant polarization states of light is also verified, indicating the possibility of achieving a resolution-lossless polarimeter. Thus, our proposed method shows a cost-effective way to realize a compact polarimeter in polarization optics.

Light-Reconfiguring Inhomogeneous Soft Helical Pitch with Fatigue Resistance and Reversibility.

Active engineering and modulation of optical spectra in a remote and fully reversible light is urgently desired in photonics, chemistry, and materials. However, the real-time regulation of multiple optical information such as wavelength, bandwidth, reflectance, and polarization is still a longstanding issue due to the lack of an appropriate photoresponsive candidate. Herein, we propose an additional "degree-of-freedom (DOF)" in a photo-modulated soft helix, and build up an unprecedented inhomogeneous helical pitch length with light-reconfiguring property, fatigue resistance, and reversibility. For the working model, the intrinsic chiral photoswitch LBC5 is employed as an actuator to modulate the helical pitch length, which is proportional to the irradiation intensity, and the unique broadband absorbance photo-modulator BTA-C5 is incorporated as an attenuator of the transmitted light to decrease its intensity along the sample thickness, therefore successfully adding another controlled DOF on the pitch length distribution (i.e., homogeneous or inhomogeneous) apart from the common soft helix with only a single DOF on the pitch length. The absorbance photo-modulator BTA-C5 with a unique variable broadband absorption enables the light to reconfigure the helical pitch from homogeneous to inhomogeneous, thereby achieving the robust fatigue-resistance establishment of reversible spectral programming. The established light-reconfigurable inhomogeneous helical pitch with the photoresponsive modulator BTA-C5 can provide a breakthrough to control absorbance and chirality, especially for dynamically broadening and narrowing the bandwidth on demand, and further enable the ever-desired broadband NIR circularly polarized luminescence (CPL) with a high dissymmetry factor glum of up to 1.88. The cutting-edge photoswitchable inhomogeneous soft helical pitch provides access to multi-freedom control in soft materials, optics, biophotonics, and other relevant fields.

Three-dimensional control of the helical axis of a chiral nematic liquid crystal by light.

Chiral nematic liquid crystals--otherwise referred to as cholesteric liquid crystals (CLCs)--are self-organized helical superstructures that find practical application in, for example, thermography, reflective displays, tuneable colour filters and mirrorless lasing. Dynamic, remote and three-dimensional control over the helical axis of CLCs is desirable, but challenging. For example, the orientation of the helical axis relative to the substrate can be changed from perpendicular to parallel by applying an alternating-current electric field, by changing the anchoring conditions of the substrate, or by altering the topography of the substrate's surface; separately, in-plane rotation of the helical axis parallel to the substrate can be driven by a direct-current field. Here we report three-dimensional manipulation of the helical axis of a CLC, together with inversion of its handedness, achieved solely with a light stimulus. We use this technique to carry out light-activated, wide-area, reversible two-dimensional beam steering--previously accomplished using complex integrated systems and optical phased arrays. During the three-dimensional manipulation by light, the helical axis undergoes, in sequence, a reversible transition from perpendicular to parallel, followed by in-plane rotation on the substrate surface. Such reversible manipulation depends on experimental parameters such as cell thickness, surface anchoring condition, and pitch length. Because there is no thermal relaxation, the system can be driven either forwards or backwards from any light-activated intermediate state. We also describe reversible photocontrol between a two-dimensional diffraction state, a one-dimensional diffraction state and a diffraction 'off' state in a bilayer cell.

Large-area, low-cost near-infrared meta-surface reflector based on a pixelated two-dimensional silicon disk array.

All-dielectric meta-surfaces composed of dielectric meta-atoms with electric and magnetic multipole resonances provide a low loss alternative to plasmonic meta-surfaces in some optical research fields such as meta-lens and meta-surface holography. We utilize the digital holography lithography technique to obtain the large area meta-surface perfect reflector made of high refractive index and low loss silicon discs arrays, with the capability to delicately control the optical response in the near infrared spectrum. Three types of meta-surface reflectors (discs, truncated cones and diamond-shaped discs) were fabricated, which correspondingly exhibited nearly 1 peak reflectance and greater than 97% average reflectance in their respective perfect reflectance spectral regions. Digital holography lithography only takes 4 min to fabricate millions of photoresist disks over an area of 100 mm2, which is high processing efficiency and low cost. The fabrication strategy opens a new avenue for the production of large-area meta-surfaces in the optical field, especially in the mass production of optical communication devices, semiconductor lasers, etc.

Low-threshold organic lasing from a square optical microcavity fabricated by imaging holography.

We propose and demonstrate the versatile fabrication of optical subwavelength microcavities by using imaging holography. As a demonstration, a peculiar square optical microcavity with a periodicity of 400 nm is imaged from a micrometer-scale diffractive optical element, attributing to the interference by the refocusing of the multiple diffractive beams. By spin-coating an active conjugated polymer onto the microcavity, highly directional laser emission with a low pumping threshold of 0.5 kW/cm2 is achieved. The effect of the film thickness on the lasing performance is also investigated. This imaging holography technique can enable convenient and easy fabrication of optical microcavities with subwavelength features, hence providing significant flexibility and richness on engineering the optical response of photonic nanostructures.

Electrically/optically tunable photo-aligned hybrid nematic liquid crystal Dammann grating.

In this Letter, we disclose a Dammann grating (DG) based on the hybrid photo-aligned nematic liquid crystals (LCs). The LC cell is composed of two substrates, wherein the first substrate is treated to provide the homeotropic alignment, and the other substrate is set to provide an in-plane, patterned alignment with a mutually orthogonal easy axis in the neighboring alignment domains. Thus, the fabricated polarization independent DG generates an optical array of equally distributed energy, which is characterized by a diffraction efficiency of more than 58%, a response time <1 ms, and the driving voltage 3 V/µm. Furthermore, the optically active alignment layer provides the optical tunability and reconfigurability for the proposed DG. With these advantageous parameters, these DGs can be applied in modern applications.

Preparation and optical properties of Fe3O4 nanoparticles-doped blue phase liquid crystal.

The magnetic Fe3O4 nanoparticle-doped blue phase liquid crystal (BPLC) was found to have a relatively strong contrast ratio in magnetic-addressed display performance compared to the composites in other phases; this is a new application of the BPLC and a way to prepare a new type of power-free magnetically-driven LC flexible display.

The effectiveness of intra-aortic balloon pump for myocardial infarction in patients with or without cardiogenic shock: a meta-analysis and systematic review.

BACKGROUND: Conflicting reports on the efficacy of intra-aortic balloon pump (IABP) during percutaneous coronary intervention (PCI) incited us to evaluate the utility of IABP in patients with acute myocardial infarction (AMI). METHODS: Randomized clinical trials comparing patients, who received IABP vs. control (no IABP) during PCI, were hand-searched from MEDLINE, Cochrane, and EMBASE databases using the terms "intra-aortic balloon pump, percutaneous coronary intervention, myocardial infarction, acute coronary syndrome". Mortality rate (30-day and 6-month mortality) was the primary outcome, while the secondary outcomes included 30-day bleeding rate, reinfarction rate, revascularization rate and stroke rate. RESULTS: Pooled results of the seven trials identified indicated that the 30-day and 6-month mortality rate were not significantly different between the IABP and control groups. However, in patients with MI, but without cardiogenic shock (CS), IABP was associated with lower odds of 30-day mortality (OR = 0.35, p = 0.015) and 6-month mortality (OR = 0.41, p = 0.020). The pooled results of 30-day bleeding rate was not significantly higher in patients with IABP than the control group, but for the patients with high risk PCI without CS, it was higher in patients with IABP than the control group (OR = 1.58, p = 0.009). The re-infarction, revascularization, and the stroke rate at 30 days of follow-up were not significantly different between the two groups. CONCLUSIONS: The present results do not favor the clinical utility of IABP in patients suffering high-risk PCI without CS and AMI complicated with CS. However, in patients with AMI, but without CS, IABP may reduce the 30-day and 6-month mortality rate.

Frequency-Driven Self-Organized Helical Superstructures Loaded with Mesogen-Grafted Silica Nanoparticles.

Adding colloidal nanoparticles into liquid-crystal media has become a promising pathway either to enhance or to introduce novel properties for improved device performance. Here we designed and synthesized new colloidal hybrid silica nanoparticles passivated with a mesogenic monolayer on the surface to facilitate their organo-solubility and compatibility in a liquid-crystal host. The resulting nanoparticles were identified by 1 H NMR spectroscopy, TEM, TGA, and UV/Vis techniques, and the hybrid nanoparticles were doped into a dual-frequency cholesteric liquid-crystal host to appraise both their compatibility with the host and the effect of the doping concentration on their electro-optical properties. Interestingly, the silica-nanoparticle-doped liquid-crystalline nanocomposites were found to be able to dynamically self-organize into a helical configuration and exhibit multi-stability, that is, homeotropic (transparent), focal conic (opaque), and planar states (partially transparent), depending on the frequency applied at sustained low voltage. Significantly, a higher contrast ratio between the transparent state and scattering state was accomplished in the nanoparticle-embedded liquid-crystal systems.

[Efficacy of modified Roux-en-Y gastric bypass in the treatment of non-obese type 2 diabetes mellitus:one year follow-up].

OBJECTIVE: To evaluate the one year effect of modified Roux-en-Y gastric bypass (RYGP) in the treatment of non-obese type 2 diabetes and to investigate the reasonable indications for surgery. METHODS: Totally 72 patients diagnosed as type 2 diabetes underwent RYGP from May 2009 to June 2010. There were 45 male and 27 female patients, with an average age of (47 ± 10) years. Preoperative body mass index (BMI) of the patients was 18.69 to 31.22 kg/m(2), average (26 ± 4) kg/m(2). The follow-up data included fasting plasma glucose (FPG), 2 h plasma glucose after oral glucose challenge (2hPG), weight, BMI and medication usage in 1, 3, 6 and 12 months postoperative; hemoglobin A1c (HbA1c), fasting C-peptide (C-P), fasting serum insulin (Fins) and homeostasis model assessment of insulin resistance index (HOMA-IR) in 6 and 12 months postoperative, respectively. RESULTS: Compared with the preoperative, FPG, 2hPG, weight and BMI in 1, 3, 6 and 12 months after surgery were improved (t = 7.014 to 10.254, P = 0.000), while HbA1c, C-P and HOMA-IR in 6 and 12 months after surgery were improved (t = 1.782 to 7.789, P = 0.000 to 0.103) and there was no significant difference in Fins (P > 0.05). The rates of complete remission in 1, 3, 6 and 12 months after surgery were gradually improved to 22.2%, 27.8%, 36.1% and 60.6%, respectively, and the rate of remission in 1 year was 94.3%. The complete remission of 1 year after surgery was associated with normal C-P, insulin antibody and oral antidiabetic drugs (χ(2) = 11.730, P = 0.003; χ(2) = 7.131, P = 0.028;χ(2) = 6.149, P = 0.046). CONCLUSIONS: Modified RYGP is safely and effectively in the treatment of no-obese type 2 diabetes patients. The function of islet cells is significantly improved after operation. Especially for the patients of whom C-P is normal, insulin antibody is negative before surgery, the rate of complete remission after 1 year is better.

Dynamically actuated soft heliconical architecture via frequency of electric fields.

Dynamic electric field frequency actuated helical and spiral structures enable a plethora of attributes for advanced photonics and engineering in the contemporary era. Nevertheless, leveraging the frequency responsiveness of adaptive devices and systems within a broad dynamic range and maintaining restrained high-frequency induced heating remain challenging. Herein, we establish a frequency-actuated heliconical soft architecture that is quite distinct from that of common frequency-responsive soft materials. We achieve reversible modulation of the photonic bandgap in a wide spectral range by delicately coupling the frequency-dependent thermal effect, field-induced dielectric torque and elastic equilibrium. Furthermore, an information encoder prototype without the aid of complicated algorithm design is established to analogize an information encoding and decoding process with a more convenient and less costly way. A technique for taming and tailoring the distribution of the pitch length is exploited and embodied in a prototype of a spatially controlled soft photonic cavity and laser emission. This work demonstrates a distinct frequency responsiveness in a heliconical soft system, which may not merely inspire the interest in field-assisted bottom-up molecular engineering of soft matter but also facilitate the practicality of adaptive photonics.

Correlation Analysis of the Change Law of Index Gas and Active Functional Groups in the Process of High-Temperature Spontaneous Combustion of Minerals in the Fushun West Mine.

The spontaneous combustion of underground minerals causes huge property losses and ecological damage. Coal and oil shale are co-associated minerals in the Fushun West Mine, and both have the ability to undergo oxidative spontaneous combustion. To study the effect of microstructure changes on the macroscopic gas product concentration during the mineral oxidation spontaneous combustion process in the Fushun West Mine, this study used a high-temperature temperature-programmed test to obtain the change trend of gas product concentration in different oxidation stages of minerals. Using Fourier transform infrared spectroscopy technology, the changes in active functional groups of surface molecules during the process of mineral oxidation and spontaneous combustion were identified. Finally, using the gray correlation degree, correlation analysis between the concentration of gas products and the concentration of active functional groups in different oxidation stages was carried out. The key reactive functional groups affecting mineral spontaneous combustion were identified. The essential reason for the change in the gas product was revealed.

Expression characteristics of heparanase in colon carcinoma and its close relationship with cyclooxygenase-2 and angiogenesis.

BACKGROUND/AIMS: Heparanase (HPA) influences tumourigenesis and tumour progression by various mechanisms, including angiogenesis. Cyclooxygenase-2 (COX-2) was strongly correlated with microvessel density, and that COX-2 expression is up-regulated by HPA in esophageal cancer. In this study, we examined the relationship between HPA expression and that of COX-2 in colon carcinoma. The aim of this study was to determine whether the expression of HPA is related to the angiogenesis in colorectal cancer and whether it could be involved in clinical behaviour of colon carcinoma. METHODOLOGY: HPA and COX-2 was analyzed with Immunohistochemistry and Western blot. Microvessels in colon carcinoma were examined by using anti-CD34 antibody. Statistical analysis was applied to test for the prognostic and diagnostic associations. RESULTS: Immunohistochemistry revealed that HPA was expressed at low level in normal colonic mucosa (4/78, 5.1%), but at higher level in tumor tissues (63/78, 80.7%) and closely correlated with tumor lymph node metastasis (p < 0.05). This result was further confirmed by Western blot analysis. Furthermore, carcinomas with high HPA expression demonstrated high COX-2 expression and high MVD (microvesseldensity) labelled with CD34. In addition, mortality was higher in patients with HPA+ phenotype and HPA was an independent predictor of overall survival (p < 0.05). CONCLUSIONS: Our findings indicated that HPA might be an important biomarker for malignant transformation and be involved in promoting colon carcinoma metastasis by increasing angiogenesis.

Photoprogrammable Mesogenic Soft Helical Architectures: A Promising Avenue toward Future Chiro-Optics.

Mesogenic soft materials, having single or multiple mesogen moieties per molecule, commonly exhibit typical self-organization characteristics, which promotes the formation of elegant helical superstructures or supramolecular assemblies in chiral environments. Such helical superstructures play key roles in the propagation of circularly polarized light and display optical properties with prominent handedness, that is, chiro-optical properties. The leveraging of light to program the chiro-optical properties of such mesogenic helical soft materials by homogeneously dispersing photosensitive chiral material into an achiral soft system or covalently connecting photochromic moieties to the molecules has attracted considerable attention in terms of materials, properties, and potential applications and has been a thriving topic in both fundamental science and application engineering. State-of-the-art technologies are described in terms of the material design, synthesis, properties, and modulation of photoprogrammable chiro-optical mesogenic soft helical architectures. Additionally, the scientific issues and technical problems that hinder further development of these materials for use in various fields are outlined and discussed. Such photoprogrammable mesogenic soft helical materials are competitive candidates for use in stimulus-controllable chiro-optical devices with high optical efficiency, stable optical properties, and easy miniaturization, facilitating the future integration and systemization of chiro-optical chips in photonics, photochemistry, biomedical engineering, chemical engineering, and beyond.