By tailoring the dimensions of the graphene nano-taper and selecting the appropriate Fermi energy, a desired near-field gradient force for nanoparticle trapping is achievable under relatively low-intensity illumination from a THz source when the particles are positioned near the nano-taper's front vertex. The designed system, incorporating a graphene nano-taper of 1200 nm length and 600 nm width, along with a 2 mW/m2 THz source, effectively trapped polystyrene nanoparticles of 140 nm, 73 nm, and 54 nm diameters. The trap stiffnesses for these nanoparticles were measured to be 99 fN/nm, 2377 fN/nm, and 3551 fN/nm, respectively, at Fermi energies of 0.4 eV, 0.5 eV, and 0.6 eV. The plasmonic tweezer, a highly precise and non-contact manipulation tool, holds significant promise for biological applications, as is widely recognized. Our investigations successfully validate the ability of the proposed tweezing device—with characteristics of L = 1200nm, W = 600nm, and Ef = 0.6eV—to manipulate nano-bio-specimens. The isosceles-triangle-shaped graphene nano-taper can trap, at its front tip, neuroblastoma extracellular vesicles that are released by neuroblastoma cells and play a significant role in modulating the function of neuroblastoma and other cell populations, achieving a minimum size capture of 88nm at the prescribed source intensity. Given neuroblastoma extracellular vesicles, the trap stiffness is ky = 1792 femtonewtons per nanometer.

A quadratic phase aberration compensation approach, numerically accurate, was proposed for digital holography. Morphological features of the object phase are extracted by applying a Gaussian 1-criterion-based phase imitation method, involving the successive operations of partial differentiation, filtering, and integration. Neurosurgical infection By minimizing the metric of the compensation function, using a maximum-minimum-average-standard deviation (MMASD) metric, our adaptive compensation method yields optimal compensated coefficients. Empirical evidence, in the form of simulations and experiments, affirms the method's efficacy and robustness.

Employing numerical and analytical strategies, our study focuses on the ionization processes of atoms in strong orthogonal two-color (OTC) laser fields. The calculated distribution of photoelectron momenta shows two recognizable shapes: a shape resembling a rectangle and a shoulder-like shape. The placement of these shapes correlates with adjustments made to the laser parameters. A strong-field model, enabling a precise quantification of the Coulomb influence, reveals the origin of these two structures in the attosecond response of atomic electrons to light, specifically within the framework of OTC-induced photoemission. Derived are some straightforward correlations between the positions of these structures and reaction times. The mappings facilitate the creation of a two-color attosecond chronoscope for measuring electron emission timing, an essential requirement for precise manipulation using OTC methods.

Flexible substrates for surface-enhanced Raman spectroscopy (SERS) have received extensive interest because of their convenience in sample preparation and on-site analysis capability. Fabricating a versatile, bendable SERS substrate for real-time detection of analytes, whether within water or on heterogeneous solid surfaces, remains an intricate fabrication problem. A transparent and adaptable substrate for SERS analysis is presented, utilizing a wrinkled polydimethylsiloxane (PDMS) film. This film's corrugated structure is derived from a pre-patterned aluminum/polystyrene bilayer, followed by the deposition of silver nanoparticles (Ag NPs) via thermal evaporation. The as-fabricated SERS substrate shows an impressive enhancement factor of 119105, combined with good signal uniformity (RSD of 627%) and excellent reproducibility between batches (RSD of 73%) when measuring rhodamine 6G. Despite 100 cycles of bending and torsion, the Ag NPs@W-PDMS film retains its high detection sensitivity, showcasing its mechanical robustness. Of particular significance, the Ag NPs@W-PDMS film exhibits flexibility, transparency, and a light weight, enabling both its ability to float on the surface of water and its conformal contact with curved surfaces for in situ detection. Detection of malachite green, even at concentrations as low as 10⁻⁶ M, in aqueous solutions and on apple peels, is readily achievable with a portable Raman spectrometer. Therefore, the projected efficacy and plasticity of this SERS substrate suggest its potential for in-field, immediate monitoring of pollutants for real-world scenarios.

In the practical application of continuous-variable quantum key distribution (CV-QKD) setups, the idealized Gaussian modulation is often discretized, causing a transition to discretized polar modulation (DPM). This discretization degrades the accuracy of parameter estimation, ultimately leading to an overestimation of excess noise levels. In the asymptotic context, the estimation bias resulting from DPM is wholly determined by modulation resolution, and it takes on a quadratic structure. Using the closed-form expression of the quadratic bias model, a calibration process for estimated excess noise is implemented to produce an accurate estimation. The statistical examination of residual errors from the model determines the upper limit for the estimated excess noise and the lower limit for the secret key rate. Simulation results, using a modulation variance of 25 and 0.002 excess noise, indicate that the proposed calibration method eliminates a 145% estimation bias, enhancing the performance and feasibility of DPM CV-QKD.

The paper details a high-precision method to measure the axial clearance between rotor and stator components in confined areas. Through the utilization of all-fiber microwave photonic mixing, the optical path structure is now established. Evaluation of the total coupling efficiency across a spectrum of fiber probe working distances, spanning the entire measurement range, was performed using both Zemax software and a theoretical model to enhance accuracy and expand the range of measurement. The system's performance underwent rigorous experimental evaluation. Within the 0.5-20.5 mm range of axial clearance, experimental results show a measurement accuracy greater than 105 micrometers. check details Compared to the preceding methods, the accuracy of measurements has experienced a substantial enhancement. The probe's diameter, decreased to a mere 278 mm, now proves more suitable for the task of measuring axial clearances in the constrained spaces within rotating machines.

A spectral splicing method (SSM) for distributed strain sensing, leveraging optical frequency domain reflectometry (OFDR), is presented and tested, demonstrating its capabilities in achieving kilometer-long measurement lengths, higher sensitivity, and a 104 range. The SSM's application of the traditional cross-correlation demodulation technique moves from the original centralized data processing to a segmented processing method. Precise spectral splicing of each segment is facilitated by spatial correction, leading to strain demodulation. By strategically segmenting the process, accumulated phase noise over wide sweeps and long distances is efficiently suppressed, enabling processing of sweep ranges from the nanometer to ten-nanometer scale and improving sensitivity to strain. The spatial position correction, meanwhile, addresses inaccuracies in spatial positioning caused by segmentation. This correction reduces errors from the ten-meter level to the millimeter level, enabling precise splicing of spectra and expanding the spectral range, thereby broadening the strain quantification capacity. Across a 1km stretch in our experiments, a strain sensitivity of 32 (3) was observed, achieving a spatial resolution of 1cm and broadening the strain measurement range to cover the value of 10000. According to our assessment, this method provides a new solution for high precision and broad-range OFDR sensing at the kilometer level.

The holographic near-eye display's wide-angle view, unfortunately, suffers from a cramped eyebox, compromising its 3D visual immersion. This paper details an opto-numerical approach to enlarging the eyebox in such devices. The hardware implementation of our solution increases the eyebox by placing a grating of frequency fg inside a display that does not create a pupil. The grating enhances the eyebox's dimensions, leading to an increase in the possible range of eye movement. Our solution's numerical component is an algorithm, facilitating the precise encoding of wide-angle holographic information, thereby enabling accurate object reconstruction at any observer position inside the extended eyebox. The algorithm's development methodology incorporates phase-space representation, supporting the analysis of holographic information and the effect of the diffraction grating on the wide-angle display system's performance. A demonstration of accurate encoding for wavefront information components within eyebox replicas is presented. This method provides an efficient solution to the problem of missing or incorrect views in wide-angle near-eye displays with multiple eyeboxes. In addition, this investigation scrutinizes the interplay of space and frequency in the object-eyebox interaction, focusing on the distribution of hologram data across multiple eyebox counterparts. We experimentally evaluate the functionality of our solution within a near-eye augmented reality holographic display, which possesses a maximum field of view of 2589 degrees. For all eye positions contained within the expanded eyebox, the optical reconstructions show a correct representation of the object.

Upon electrical field application, the alignment of nematic liquid crystal in a liquid crystal cell with a comb electrode configuration can be effectively controlled. endocrine-immune related adverse events In varying directional zones, the incoming laser beam experiences diverse deflection angles. Modifying the angle at which the laser beam strikes results in a modulated reflection of the laser beam on the boundary of the shifting liquid crystal molecular structure. Guided by the preceding conversation, we subsequently show the modulation of liquid crystal molecular orientation arrays in nematicon pairs.