This paper investigates the energy-conscious routing methodology for satellite laser communication and develops a satellite degradation model. The model's data informs our proposal of an energy-efficient routing scheme using a genetic algorithm. Relative to shortest path routing, the proposed method boosts satellite longevity by roughly 300%. Network performance shows minimal degradation, with the blocking ratio increasing by only 12% and service delay increasing by just 13 milliseconds.

Metalenses boasting extended depth of field (EDOF) facilitate broader image coverage, opening new avenues in microscopy and imaging. Forward-designed EDOF metalenses currently face issues like asymmetric point spread functions and non-uniform focal spot distribution, compromising image quality. We present a double-process genetic algorithm (DPGA) solution for the inverse design of EDOF metalenses to address these problems. By strategically employing different mutation operators in two subsequent genetic algorithm (GA) runs, the DPGA algorithm exhibits superior performance in finding the optimal solution within the entire parameter space. Using this strategy, 1D and 2D EDOF metalenses, working at 980nm, are each independently designed, leading to a considerable enhancement of depth of focus (DOF) in comparison to traditional focusing systems. Subsequently, a uniform focal spot is consistently maintained, thereby ensuring stable longitudinal imaging quality. In biological microscopy and imaging, the proposed EDOF metalenses show substantial potential; furthermore, the DPGA scheme's application extends to the inverse design of various other nanophotonics devices.

The ever-increasing importance of multispectral stealth technology, including terahertz (THz) band capabilities, will be evident in modern military and civil applications. ARRY-162 Two flexible and transparent metadevices, with a modular design foundation, were developed for multispectral stealth, covering the visible, infrared, THz, and microwave spectra. Three essential functional blocks for achieving IR, THz, and microwave stealth are meticulously designed and produced utilizing flexible and transparent films. Two multispectral stealth metadevices can be effortlessly crafted through modular assembly, which entails the incorporation or exclusion of covert functional components or constituent layers. The dual-band broadband absorption capabilities of Metadevice 1, covering both THz and microwave frequencies, average 85% absorptivity within the 0.3-12 THz spectrum and surpass 90% in the 91-251 GHz frequency range, making it well-suited for THz-microwave bi-stealth applications. Metadevice 2, designed for infrared and microwave bi-stealth, exhibits absorptivity exceeding 90% across the 97-273 GHz spectrum and shows low emissivity of approximately 0.31 within the 8-14 m range. Under curved and conformal conditions, both metadevices remain optically transparent and maintain a high level of stealth capability. An alternative method for creating and manufacturing flexible, transparent metadevices for multispectral stealth applications, especially on non-planar surfaces, is provided by our work.

A new surface plasmon-enhanced dark-field microsphere-assisted microscopy method, which we present here for the first time, is used to image both low-contrast dielectric objects and metallic ones. Compared to metal plate and glass slide substrates, we find that an Al patch array substrate improves the resolution and contrast in dark-field microscopy (DFM) imaging of low-contrast dielectric objects. Hexagonally arranged SiO nanodots, with a diameter of 365 nanometers, are resolved on three substrates, showing contrast varying between 0.23 and 0.96. In comparison, 300-nm-diameter, hexagonally close-packed polystyrene nanoparticles are only visible on the Al patch array substrate. The resolution capability of microscopy can be further enhanced with the use of dark-field microsphere assistance, enabling the differentiation of an Al nanodot array with a 65nm diameter for the nanodots and a 125nm center-to-center separation, a feat presently unachievable through conventional DFM. Surface plasmon excitation, in conjunction with microsphere focusing, results in an object experiencing enhanced local electric field (E-field) evanescent illumination. ARRY-162 The amplified local electric field functions as a near-field excitation source, increasing the scattering of the object, which subsequently improves the resolution of the imaging process.

Liquid crystal (LC) terahertz phase shifters, owing to the need for substantial retardation, frequently employ thick cell gaps, thus compromising the speed of LC response. A novel liquid crystal (LC) switching method, virtually demonstrated, permits reversible transitions between three orthogonal in-plane and out-of-plane orientations, thereby enhancing the response and broadening the spectrum of continuous phase shifts. The LC switching process is realized through the use of two substrates, each having two pairs of orthogonal finger electrodes and one grating electrode dedicated to in-plane and out-of-plane manipulations. Voltage application leads to an electric field that drives the switching mechanism among the three distinct orientational states, facilitating a quick response.

This report details an investigation of secondary mode suppression within single longitudinal mode (SLM) 1240nm diamond Raman lasers. ARRY-162 Utilizing a three-mirror V-shaped standing-wave cavity incorporating an intracavity lithium triborate (LBO) crystal to minimize secondary modes, we obtained stable SLM output with a maximum output power of 117 W and a slope efficiency of 349 percent. The necessary coupling strength to suppress secondary modes, especially those induced by stimulated Brillouin scattering (SBS), is evaluated. The beam profile frequently shows a concurrence between SBS-generated modes and higher-order spatial modes, which can be suppressed by means of an intracavity aperture. Numerical computations demonstrate a heightened probability of observing higher-order spatial modes in an apertureless V-cavity, in contrast to two-mirror cavities, due to the varied longitudinal mode structures.

A novel driving scheme, to our knowledge, is presented to suppress stimulated Brillouin scattering (SBS) within master oscillator power amplification (MOPA) systems, based on the application of an external high-order phase modulation. Employing linear chirp seed sources, the SBS gain spectrum is uniformly widened, demonstrating a high SBS threshold, motivating the creation of a chirp-like signal, achieved through further signal processing and editing from a piecewise parabolic structure. The chirp-like signal, unlike the traditional piecewise parabolic signal, shares comparable linear chirp characteristics. This results in decreased driving power and sampling rate requirements, facilitating a more efficient spectral spreading approach. The three-wave coupling equation underpins the theoretical construction of the SBS threshold model. The chirp-like signal's modulation of the spectrum, when evaluated alongside flat-top and Gaussian spectra with respect to SBS threshold and normalized bandwidth distribution, demonstrates a significant improvement. In parallel, the MOPA-structured amplifier is subjected to experimental validation at a watt-class power level. Modulation of the seed source by a chirp-like signal results in a 35% and 18% improvement in the SBS threshold, at a 3dB bandwidth of 10GHz, compared to flat-top and Gaussian spectra, respectively; and the normalized threshold is the maximum among these options. Analysis of our data reveals that the observed suppression of SBS is not only predicated upon the spectrum's power distribution, but also is susceptible to improvement via optimized time domain design. This insight offers a novel approach to improving the SBS threshold in narrow-linewidth fiber lasers.

The first demonstration of acoustic impedance sensing with a sensitivity exceeding 3 MHz has, to the best of our knowledge, been achieved by employing forward Brillouin scattering (FBS) driven by radial acoustic modes in a highly nonlinear fiber (HNLF). The significant acousto-optical coupling in HNLFs facilitates a greater gain coefficient and scattering efficiency for radial (R0,m) and torsional-radial (TR2,m) acoustic modes in comparison to those in standard single-mode fiber (SSMF). A more pronounced signal-to-noise ratio (SNR) is achieved, which consequently enhances the sensitivity of measurements. Employing HNLF's R020 mode yielded a heightened sensitivity of 383 MHz/[kg/(smm2)], demonstrably superior to the 270 MHz/[kg/(smm2)] attained using R09 mode in SSMF, despite the latter's near-maximal gain coefficient. Using the TR25 mode in the HNLF, the measured sensitivity amounts to 0.24 MHz/[kg/(smm2)], still 15 times greater than the corresponding figure obtained from SSMF using the same mode. The enhanced sensitivity will facilitate more precise detection of the external environment by FBS-based sensors.

Weakly-coupled mode division multiplexing (MDM) techniques that support intensity modulation and direct detection (IM/DD) transmission represent a promising path to increase the capacity of short-reach applications, including optical interconnections. A key factor in this approach is the need for low-modal-crosstalk mode multiplexers/demultiplexers (MMUX/MDEMUX). In this paper, we first propose an all-fiber, low-modal-crosstalk orthogonal combining reception scheme for degenerate linearly-polarized (LP) modes, where signals in both degenerate modes are first demultiplexed into the LP01 mode of single-mode fibers, subsequently multiplexed into mutually orthogonal LP01 and LP11 modes of a two-mode fiber, enabling simultaneous detection. Fabricated via side-polishing, a pair of 4-LP-mode MMUX/MDEMUX devices, incorporating cascaded mode-selective couplers and orthogonal combiners, exhibit low back-to-back modal crosstalk, measured at below -1851dB, and insertion loss below 381dB across all four modes. By experiment, a stable real-time transmission of 4-mode 410 Gb/s MDM-wavelength division multiplexing (WDM) was demonstrated for 20 km of few-mode fiber. The proposed scalable scheme facilitates multiple modes of operation, potentially enabling practical implementation of IM/DD MDM transmission applications.