Silicon Nitride Waveguides for Plasmon Optical Trapping and Sensing Applications

We demonstrate a silicon nitride trench waveguide deposited with bowtie antennas for plasmonic enhanced optical trapping. The sub-micron silicon nitride trench waveguides were fabricated with conventional optical lithography in a low cost manner. The waveguides embrace not only low propagation loss and high nonlinearity, but also the inborn merits of combining micro-fluidic channel and waveguide together. Analyte contained in the trapezoidal trench channel can interact with the evanescent field from the waveguide beneath. The evanescent field can be further enhanced by plasmonic nanostructures. With the help of gold nano bowtie antennas, the studied waveguide shows outstanding trapping capability on 10 nm polystyrene nanoparticles. We show that the bowtie antennas can lead to 60-fold enhancement of electric field in the antenna gap. The optical trapping force on a nanoparticle is boosted by three orders of magnitude. A strong tendency shows the nanoparticle is likely to move to the high field strength region, exhibiting the trapping capability of the antenna. Gradient force in vertical direction is calculation by using a point-like dipole assumption, and the analytical solution matches the full-wave simulation well. The investigation indicates that nanostructure patterned silicon nitride trench waveguide is suitable for optical trapping and nanoparticle sensing applications

Printable surface hologram via nanosecond laser ablation

Holography plays a significant role in applications such as data storage, light trapping, security, and biosensors. However, traditional fabrication methods remain time-consuming, labour-intensive, complex and costly, limiting the extensive and massive production of holograms. In this thesis, a single-pulse laser ablation strategy was used to write surface gratings and zone plates. A 5 ns high-energy green laser pulse was utilized to form interference patterns on ink-based (150 nm thickness) and gold-based (4 nm thickness) substrates. The holographic recording process was completed within seconds. The periodicities for ink-based and gold-based gratings are 2.6 μm and 820 nm, respectively. The optical characteristics of the interference patterns have been computationally modeled, and diffraction patterns were observed from the fabricated grating holograms by different monochromatic wavelengths. In addition, the asymmetric zone plate was fabricated on 4.5 nm gold layer, and a well-ordered rainbow pattern with a significant diffraction angle of 32° was measured from the normal incident. An power meter experiment was also conducted to determine the diffraction efficiency of 0.8% by white light illumination. Handwritten signatures and 3D coin images were demonstrated to support the utilization of single laser ablation approach, and the fabrication methodology holds great potential in applications for optical devices

Electronic control of optical tweezers using space-time-wavelength mapping

We present a new approach for electronic control of optical tweezers by using space-time-wavelength mapping (STWM), a technique that uses time-domain modulation to control local intensity values, and hence the resulting optical force, in space. The proposed technique enables direct control of magnitude, location, and polarity of force hot-spots created by Lorentz force (gradient force). In this paper, we develop an analytical formulation of the proposed STWM technique for optical tweezing. In the case study presented here, we show that 150 fs optical pulses are dispersed in time and space to achieve a focused elliptical beam that is ~20 {\mu}m long and ~2 {\mu}m wide. By choosing the appropriate RF waveform and electro-optic modulator, we can generate multiple hot-spots with >200 pN force per pulse.Comment: 7 pages, 7 figure

Design of Partially Etched GaP-OI Microresonators for Two-Color Kerr Soliton Generation at NIR and MIR

We present and theoretically investigate a dispersion engineered GaP-OI microresonator containing a partially-etched gap of 250 nm x 410 nm in a 600 nm x 2990 nm waveguide. This gap enables a 3.25 {\mu}m wide anomalous dispersion spectral span covering both the near-infrared and the mid-infrared spectra. This anomalous dispersion is manifested by two mechanisms, being the hybridization of the fundamental TE modes around 1550 nm and the geometric dispersion of the higher order TE mode around the 3100 nm wavelengths, respectively. Two Kerr soliton combs can be numerically generated with 101 GHz and 97 GHz teeth spacings at these spectral windows. The proposed structure demonstrates the design flexibility thanks to the partially etched gap and paves the way towards potential coherent multicolor frequency comb generation in the emerging GaP-OI platform

Research Progress on Senile Sarcopenia and Its Sutritional Intervention

Sarcopenia, an age-associated loss of muscle mass and function, greatly increases the risk of fractures, falls, and death in older adults. The pathogenesis of which is mainly involves motor neuron loss, hormone imbalance, inflammatory factors, and insulin resistance, etc. Supplementing nutrients such as protein, amino acid， n-3, n-6 polyunsaturated fatty acids and vitamin and other nutrients can effectively prevent and treat the sarcopenia. This paper focuses on the pathogenesis and nutritional intervention of sarcopenia to provide a reference for the research of sarcopenia

Shear characteristics and mesoscopic damage mechanism of long time soaking red sandstone under loading and unloading conditions

The bank slope rock mass below the flood control restricted water level (145 m) in the Three Gorges Reservoir area has experienced long-term immersion in the process of reservoir water lifting and lowering; the water level changes lead to the rock mass being subjected to two working conditions, tangential loading shearing and normal unloading shearing. The difference in rock shearing characteristics directly affects the stability evaluation of bank slopes in different reservoir operation stages. Tangential loading and normal unloading shear tests were carried out on the typical feldspar quartz sandstone after different soaking days; then the characteristics changes of sandstone shear under the two stress conditions were obtained. The microscopic mechanism of the differences was revealed by solution test, SEM test, and nuclear magnetic resonance test. The results show that: (1) compared with the initial sample, after soaking for 80 days, the cohesion loss of the sample is greater than the loss of internal friction angle. The cohesion of the sample under tangential loading is reduced by 40.5%, and the internal friction Angle is only reduced by 2%, while the cohesion of the sample under normal unloading shear is reduced by 31%, and the internal friction Angle is reduced by 8%. (2) The long-term immersion of the sample results in the dissolution of the cement minerals, the gradual development and penetration of the secondary pores, and the increase of porosity. After 60 days of immersion, basically， the water content, porosity, and pore structure of the sample reach a stable state; the particle skeleton overcoming the shear action is almost no longer affected by the soaking water. This is the reason why the shear properties of the samples with long-term water saturation gradually weaken and become stable. (3) Under normal unloading shear conditions, the deviation between the main crack surface and the theoretical shear surface increases; the fracture surface is more inclined to form “S” and “M” types. The increase of the actual shear plane increases the peak shear stress that the rock can bear. Because the biggest contribution to the rock is the skeleton particle, the internal friction angle is larger, and the filling cementing material that provides cohesion makes less contribution to the tensile shear failure. The cohesion obtained by normal unloading is also lower. This study can provide basic information for the stability evaluation of wading slope in reservoir area with the fluctuation of water level and the selection of test method considering the actual working conditions

CAR-based immunotherapy for breast cancer: peculiarities, ongoing investigations, and future strategies

Surgery, chemotherapy, and endocrine therapy have improved the overall survival and postoperative recurrence rates of Luminal A, Luminal B, and HER2-positive breast cancers but treatment modalities for triple-negative breast cancer (TNBC) with poor prognosis remain limited. The effective application of the rapidly developing chimeric antigen receptor (CAR)-T cell therapy in hematological tumors provides new ideas for the treatment of breast cancer. Choosing suitable and specific targets is crucial for applying CAR-T therapy for breast cancer treatment. In this paper, we summarize CAR-T therapy’s effective targets and potential targets in different subtypes based on the existing research progress, especially for TNBC. CAR-based immunotherapy has resulted in advancements in the treatment of breast cancer. CAR-macrophages, CAR-NK cells, and CAR-mesenchymal stem cells (MSCs) may be more effective and safer for treating solid tumors, such as breast cancer. However, the tumor microenvironment (TME) of breast tumors and the side effects of CAR-T therapy pose challenges to CAR-based immunotherapy. CAR-T cells and CAR-NK cells-derived exosomes are advantageous in tumor therapy. Exosomes carrying CAR for breast cancer immunotherapy are of immense research value and may provide a treatment modality with good treatment effects. In this review, we provide an overview of the development and challenges of CAR-based immunotherapy in treating different subtypes of breast cancer and discuss the progress of CAR-expressing exosomes for breast cancer treatment. We elaborate on the development of CAR-T cells in TNBC therapy and the prospects of using CAR-macrophages, CAR-NK cells, and CAR-MSCs for treating breast cancer

422 Million Q Planar Integrated All-Waveguide Resonator with a 3.4 Billion Absorption Limited Q and Sub-MHz Linewidth

High Q optical resonators are a key component for ultra-narrow linewidth lasers, frequency stabilization, precision spectroscopy and quantum applications. Integration of these resonators in a photonic waveguide wafer-scale platform is key to reducing their cost, size and power as well as sensitivity to environmental disturbances. However, to date, the intrinsic Q of integrated all-waveguide resonators has been relegated to below 150 Million. Here, we report an all-waveguide Si3N4 resonator with an intrinsic Q of 422 Million and a 3.4 Billion absorption loss limited Q. The resonator has a 453 kHz intrinsic linewidth and 906 kHz loaded linewidth, with a finesse of 3005. The corresponding linear loss of 0.060 dB/m is the lowest reported to date for an all-waveguide design with deposited upper cladding oxide. These are the highest intrinsic and absorption loss limited Q factors and lowest linewidth reported to date for a photonic integrated all-waveguide resonator. This level of performance is achieved through a careful reduction of scattering and absorption loss components. We quantify, simulate and measure the various loss contributions including scattering and absorption including surface-state dangling bonds that we believe are responsible in part for absorption. In addition to the ultra-high Q and narrow linewidth, the resonator has a large optical mode area and volume, both critical for ultra-low laser linewidths and ultra-stable, ultra-low frequency noise reference cavities. These results demonstrate the performance of bulk optic and etched resonators can be realized in a photonic integrated solution, paving the way towards photonic integration compatible Billion Q cavities for precision scientific systems and applications such as nonlinear optics, atomic clocks, quantum photonics and high-capacity fiber communications systems on-chip.Comment: 20 pages, 10 figure