To manage engineered interferences and ultrashort light pulses, optical delay lines precisely control the temporal flow of light, inducing phase and group delays. The photonic integration of optical delay lines is vital for advanced chip-scale lightwave signal processing and pulse control functions. Photonic delay lines utilizing long, spiral-shaped waveguides commonly exhibit a significant drawback: their chip footprint, which can extend from the millimeter to centimeter scale. A scalable, high-density integrated delay line is presented, relying on the principles of a skin-depth-engineered subwavelength grating waveguide. The waveguide is termed an extreme skin-depth (eskid) waveguide. The eskid waveguide design mitigates the crosstalk phenomenon between closely located waveguides, resulting in significant chip area savings. Increasing the number of turns in our eskid-based photonic delay line readily facilitates scalability, promising a significant improvement in photonic chip integration density.

Utilizing a primary objective lens and a fiber bundle array, we have developed and present a multi-modal fiber array snapshot technique (M-FAST) employing an array of 96 compact cameras. High-resolution, multi-channel video acquisition across large areas is facilitated by our technique. A novel optical configuration, accommodating planar camera arrays, and the capability to acquire multi-modal image data are two pivotal enhancements offered by the proposed design over prior cascaded imaging systems. M-FAST, a scalable multi-modal imaging system, enables the acquisition of both snapshot dual-channel fluorescence images and differential phase contrast measurements within a 659mm x 974mm field of view with a 22-μm center full-pitch resolution.

In spite of the potential of terahertz (THz) spectroscopy in fingerprint sensing and detection, traditional sensing methods face unavoidable problems when analyzing samples present in small amounts. A novel absorption spectroscopy enhancement strategy, based on a defect 1D photonic crystal (1D-PC) structure, is presented in this letter, aimed at achieving strong wideband terahertz wave-matter interactions in trace-amount samples. Leveraging the Fabry-Perot resonance effect, one can amplify the local electric field in a thin-film specimen by altering the length of the photonic crystal defect cavity, thereby significantly enhancing the wideband signal associated with the sample's unique spectral fingerprint. This approach demonstrates a significant amplification in absorption, roughly 55 times higher, over a broad range of terahertz frequencies. This enhances the ability to distinguish between various samples, including thin lactose films. The research findings of this Letter introduce a new method for improving the comprehensive range of terahertz absorption spectroscopy used to study trace samples.

Using the three-primary-color chip array, the most straightforward full-color micro-LED displays can be implemented. Medical hydrology The AlInP-based red micro-LED and the GaN-based blue/green micro-LEDs present a notable discrepancy in their luminous intensity distribution, ultimately causing an angular color shift at varying viewing angles. Analyzing the angular variation in color difference for conventional three-primary-color micro-LEDs, this letter establishes that a homogeneous silver coating on an inclined sidewall provides limited angular regulation for micro-LED devices. Based on the provided information, the effective elimination of color shift is realized by designing a patterned conical microstructure array on the base layer of the micro-LED. Furthermore, this design regulates the emission of full-color micro-LEDs perfectly in line with Lambert's cosine law without employing external beam shaping components, and concurrently increases top emission light extraction efficiency by 16%, 161%, and 228% for red, green, and blue micro-LEDs, respectively. The full-color micro-LED display's color shift (u' v') is maintained below 0.02, corresponding with a viewing angle range of 10 to 90 degrees.

The inability of most UV passive optics to be tuned or externally modulated stems from the poor tunability inherent in wide-bandgap semiconductor materials utilized in UV operating mediums. Hafnium oxide metasurfaces, designed with elastic dielectric polydimethylsiloxane (PDMS), are explored in this study for their capacity to excite magnetic dipole resonances in the solar-blind UV region. Daratumumab chemical structure The resonant peak within the solar-blind UV region can be controlled by influencing the near-field interactions of resonant dielectric elements via adjustments to the mechanical strain of the PDMS substrate, thereby enabling or disabling the optical switch in this region. The design of the device is straightforward, enabling its use in diverse applications, including UV polarization modulation, optical communication, and spectroscopy.

We present a method for geometrically altering screens to eliminate ghost reflections, a frequent issue in deflectometry optical testing. The method under consideration alters the optical arrangement and the illumination source's region to bypass the formation of reflected rays from the undesirable surface. The ability of deflectometry to alter its layout allows for the production of custom system setups that avert the creation of obstructive secondary rays. Optical raytrace simulations serve as a cornerstone for the proposed method's justification, which is further proven by experimental results, encompassing convex and concave lens case studies. The digital masking method, in its final analysis, has limitations that are discussed.

Transport-of-intensity diffraction tomography (TIDT), a newly developed label-free computational microscopy technique, determines the three-dimensional (3D) refractive index (RI) distribution of biological samples with high precision from three-dimensional (3D) intensity-only measurements. Nonetheless, the non-interferometric synthetic aperture in TIDT is typically achieved sequentially by acquiring numerous intensity stacks throughout the focal plane, each taken at varying illumination angles, leading to a laborious and redundant data acquisition process. A parallel synthetic aperture implementation in TIDT (PSA-TIDT) with annular illumination is provided here for this objective. The matched annular illumination pattern produced a mirror-symmetric 3D optical transfer function, reflecting the analyticity of the complex phase function's upper half-plane. This characteristic facilitated the recovery of the 3D refractive index from a solitary intensity stack. High-resolution tomographic imaging served as the experimental method for validating PSA-TIDT's accuracy on various unlabeled biological samples, including human breast cancer cell lines (MCF-7), human hepatocyte carcinoma cell lines (HepG2), Henrietta Lacks (HeLa) cells, and red blood cells (RBCs).

Based on a helically twisted hollow-core antiresonant fiber (HC-ARF), the orbital angular momentum (OAM) mode generation within a long-period onefold chiral fiber grating (L-1-CFG) is examined. Regarding a right-handed L-1-CFG, we unequivocally prove through both theoretical and experimental studies that the first-order OAM+1 mode can be generated from a solely Gaussian beam input. Using helically twisted HC-ARFs with twist rates of -0.42 rad/mm, -0.50 rad/mm, and -0.60 rad/mm, three right-handed L-1-CFG specimens were fabricated. The -0.42 rad/mm twist rate specimen demonstrated a high OAM+1 mode purity of 94%. Afterwards, we display both simulated and experimental transmission spectra spanning the C-band, demonstrating sufficient modulation depths at 1550nm and 15615nm in our experiments.

Two-dimensional (2D) transverse eigenmodes were a standard method for analyzing structured light. skin infection Newly discovered 3D geometric light modes, arising as coherent superpositions of eigenmodes, have revealed novel topological indices that enable light shaping. Coupling optical vortices to multiaxial geometric rays is possible, but constrained to the azimuthal charge of the vortex. We propose a new type of structured light, multiaxial super-geometric modes, allowing for a complete coupling of radial and azimuthal indices to multiaxial rays. These modes can be produced directly within a laser cavity. Experimental verification demonstrates the adaptability of complex orbital angular momentum and SU(2) geometry, extending beyond the limitations of prior multiaxial modes, achieved through combined intra- and extra-cavity astigmatic conversions. This innovative approach offers revolutionary potential for applications like optical trapping, manufacturing, and communication systems.

Exploring all-group-IV SiGeSn lasers has unveiled a fresh approach to silicon-based illumination technologies. SiGeSn heterostructure and quantum well lasers have been successfully shown to function effectively over the past couple of years. Multiple quantum well lasers are noted in reports to experience a direct effect on their net modal gain due to the optical confinement factor. Earlier research proposed the use of a cap layer to improve the alignment of optical modes with the active region, which in turn enhances the optical confinement factor in Fabry-Perot cavity laser structures. SiGeSn/GeSn multiple quantum well (4-well) devices, featuring cap layer thicknesses of 0, 190, 250, and 290nm, were investigated using a chemical vapor deposition reactor and characterized by optical pumping in this work. Spontaneous emission is the sole emission from no-cap and thinner-cap devices; conversely, two thicker-cap devices demonstrate lasing up to 77 Kelvin, with an emission peak at 2440 nanometers and a lasing threshold of 214 kW/cm2 (250 nm cap). The consistent pattern in device performance reported in this work provides a clear roadmap for the design of electrically-injected SiGeSn quantum well lasers.

We report the development and validation of an anti-resonant hollow-core fiber capable of high-purity LP11 mode propagation over a wide wavelength range. Cladding tubes filled with a specific gas selection, through resonant coupling, are used to subdue the fundamental mode. At a length of 27 meters, the fabricated fiber demonstrates a mode extinction ratio surpassing 40dB at 1550nm and maintaining a ratio above 30dB over a wavelength range of 150nm.